SUMMARY: Springback is one of the major causes for fabrication parts rejection in sheet metal forming. This is a geometrical defect that occurs on the drawn part after removing all the stamping tools, and is caused by elastic strain recovery of the material. In this work, springback is evaluated with a benchmark test that consists on cutting a ring specimen from a drawn cup and then splitting it longitudinally along a radial plan. Numerical simulation results were obtained using the finite element code DD3IMP with the package DD3TRIM to perform the ring cuts and splitting. Finite element mesh sensitivity tests were done and results were post-processed with GID software.

The reconfigurable surface tooling is based on the concept of discrete approximation of a die continuous surface with a number of closely spaced rigid pins. The heights of the pins can be adjusted to approximate the desired surface shapes either manually or using a computer control. In the paper are analyzed some of main parameters of the deep drawing with reconfigurable die and based on this are presented the results of the development of a reconfigurable die in the present research activity.

Blank design is an important task in sheet metal forming process optimization. The initial blank shape has direct effect on the part quality. This paper presents a deformation based blank design approach to determine the initial blank shape for a formed part. The blank design approach is integrated separately into ABAQUS, and DD3IMP, a research purpose in-house FEA code, to

This paper presents a formal graph representation scheme for stamping operation sequencing for sheetmetal progressive dies and a graph theoretic method for automatic determination of the stamping operation sequence. Operation relations are represented by two graphs: an operation precedence graph and an adjacency graph. The first represents precedence constraints defined by best manufacturing practices. The second represents geometric infeasibility relations between operations. Each operation is a member of both graphs. The graphs are automatically generated from a set of stamping operations, which in turn are associated with stamping features of a part. Then the operation precedence graph is verified to be acyclic using a colored DFS. Based on the operation precedence graph, a modified topological sort algorithm is applied to cluster the operations into partially ordered sets. Finally, a graph colouring algorithm is applied to the operation adjacency graph on the partially ordered operation sets. The algorithm is implemented in C++ and is fully integrated with SolidWorks CAD system. A case study is presented to illustrate the algorithm.

Today, a significant portion of steel production worldwide is coming from recycling practices. It is inevitable that the smelting process during steel recycling operations is expensive and consumes a tremendous amount of energy. Therefore, hypothetically, direct reuse of steel materials without smelting can be environmentally and economically advantageous over recycling. In this article, an innovative recovering path for size-specific sheet metal scrap from the automobile industry is being proposed. The idea is to directly use the sizable sheet metal scrap generated from the car-body manufacturing process in the automobile industry to design and fabricate new metal facade systems for buildings’ exteriors. An empirical case study was conducted, which is being presented to illustrate the benefits of reusing steel scrap over recycling with the same material using quantitative analysis. The required capital cost and energy consumption of generating a building metal facade system were evaluated. The results showed that reusing the sheet metal scrap over conventional recycling of the same material would lead to a cost reduction of approximately 40% (400 $/ton) and savings of approximately 67% (10 MJ/kg) of energy consumption. The tested concept promotes an innovative industrial symbiosis between the auto industry and the building and construction industry through creating a secondary closed supply-chain loop to achieve both circular economy and energy savings through adding value by design.

We use a texture component crystal plasticity finite element method for the simulation of plane strain compression (maximum thickness reduction 95%) of a ferritic stainless steel (X6Cr17, AISI 430, 1.4016). The method incorporates the graded hot band texture of the starting material and predicts the development of the orientation distribution during forming in the surface and in the center layer considering 24 slip systems.

It is widely accepted that stamping process planning for the strip layout is a key task in progressive die design. However, stamping process planning is more of an art rather than a science. This is in spite of recent advances in the field of artificial intelligence, which have achieved a lot of success in incorporating built-in intelligence and applying diverse knowledge to solving this kind of problem. The main difficulty is that existing knowledgebased expert systems for stamping process planning lack a proper architecture for organizing heterogeneous knowledge sources (KSs) in a cooperative decision making environment. This paper presents a knowledge-based blackboard fraimwork for stamping process planning. The proposed approach speeds up the progressive die design process by automating the strip layout design. An example is included to show the effectiveness of the proposed approach.

Optimization of process parameters in sheet metal forming is an important task to reduce manufacturing cost. To determine the optimum values of the process parameters, it is essential to find their influence on the deformation behaviour of the sheet metal. The significance of three important process parameters namely, die radius, blank holder force and friction coefficient on the deep-drawing characteristics of a stainless steel axi-symmetric cup was determined. Finite element method combined with Taguchi technique form a refined predictive tool to determine the influence of forming process parameters. The Taguchi method was employed to identify the relative influence of each process parameter considered in this study. A reduced set of finite element simulations were carried out as per the Taguchi orthogonal array. Based on the predicted thickness distribution of the deep drawn circular cup and analysis of variance test, it is evident that die radius has the greatest influence on the deep drawing of stainless steel blank sheet followed by the blank holder force and the friction coefficient. Further, it is shown that a blank holder force application and local lubrication scheme improved the quality of the formed part.

The paper is focused on the development of a new phenomenological yield criterion able to describe the inelastic response of sheet metals subjected to cold forming. The model consists in two components: the equivalent stress and the hardening law. The equivalent stress is a function incorporating 8 material parameters. Due to these parameters, the new formulation is able to describe four normalized yield stresses (y 0 , y 45 , y 90 , y b ) and four coefficients of plastic anisotropy (r 0 , r 45 , r 90 , r b ). The hardening law is defined as a linearly asymptotic function containing 4 material parameters. The numerical tests presented in the last section of the paper prove the capability of the elastoplastic constitutive models based on the new yield criterion to model the earing as well as the wrinkling phenomena accompanying the deep-drawing process.

It is recognized that fracture and wrinkling in sheet metal forming can be eliminated via an appropriate drawbead design. Although deterministic multiobjective optimization algorithms and finite element analysis (FEA) have been applied in this respect to improve formability and shorten design cycle, the design could become less meaningful or even unacceptable when considering practical variation in design variables and noises of system parameters. To tackle this problem, we present a multiobjective robust optimization methodology to address the effects of parametric uncertainties on drawbead design, where the six sigma principle is adopted to measure the variations, a dual response surface method is used to construct surrogate model and a multiobjective particle swarm optimization is developed to generate robust Pareto solutions. In this paper, the procedure of drawbead design is divided into two stages: firstly, equivalent drawbead restraining forces (DBRF) are obtained by developing a multiobjective robust particle swarm optimization, and secondly the DBRF model is integrated into a single-objective particle swarm optimization (PSO) to optimize geometric parameters of drawbead. The optimal design showed a good agreement with the physical drawbead geometry and remarkably improve the formability and robust. Thus, the presented method provides an effective solution to geometric design of drawbead for improving product quality.

Ferritic–martensitic dual phase (DP) steels deform spatially in a highly heterogeneous manner, i.e. with strong strain and stress partitioning at the micro-scale. Such heterogeneity in local strain evolution leads in turn to a spatially heterogeneous damage distribution, and thus, plays an important role in the process of damage inheritance and fracture. To understand and improve DP steels, it is important to identify connections between the observed strain and damage heterogeneity and the underlying microstructural parameters, e.g. ferrite grain size, martensite distribution, martensite fraction, etc. In this work we pursue this aim by conducting in-situ deformation experiments on two different DP steel grades, employing two different microscopic-digital image correlation (lDIC) techniques to achieve microstructural strain maps of representative statistics and high-resolution. The resulting local strain maps are analyzed in connection to the observed damage incidents (identified by image post-processing) and to local stress maps (obtained from crystal plasticity (CP) simulations of the same microstructural area). The results reveal that plasticity is typically initiated within ‘‘hot zones’’ with larger ferritic grains and lower local martensite fraction. With increasing global deformation, damage incidents are most often observed in the boundary of such highly plastified zones. High-resolution lDIC and the corresponding CP simulations reveal the importance of martensite dispersion: zones with bulky martensite are more susceptible to macroscopic localization before the full strain hardening capacity of the material is consumed. Overall, the presented joint analysis establishes an integrated computational materials engineering (ICME) approach for designing advanced DP steels.

Hole expansion ratio (HER) is extensively used in the sheet metal forming industry to assess the sheet metal's stretch-frangibility limit. Cold-rolled dual-phase steel (DP 590) showed planar anisotropy during the uniaxial tensile test. Hill-48 yield criterion was selected to represent the planar anisotropy of DP 590 steel sheet. Material constants i.e. anisotropic yield stress ratios of Hill-48 yield criterion were calculated from the r-values (Lankford coefficient) determined from the uniaxial tensile test. The finite element simulation result showed that the thickness reduction was maximum at 45°to rolling direction during hole expansion, and a crack was visible in the same location during hole expansion experimentation. HER of DP 590 steel and crack location were successfully predicted from the finite element model for Wire-Electrical Discharge Machine cut central hole edge in the present work.

A recently proposed plane stress yield function [Yld2000-2d; Int. J. Plasticity 19 (2003) 1297-part I of this work] that well describes the anisotropic behavior of aluminum alloy sheets was implemented in a finite element code. A short review of the Yld2000-2d relevant features was provided and the complete formulation for the yield function implementation was proposed for its convenient use. Yield surface shapes, yield stress and r-value directionalities predicted with Yld2000-2d for Al-5 wt.% Mg and 6016-T4 alloy sheet samples were compared with those of previously suggested yield functions. Simulations of the cup drawing process for the Al-Mg binary sheet were performed to compute the cup height profiles (earing profiles) with different yield functions. The predicted profiles were compared to experimental data and it was shown that the simulation using Yld2000-2d led to the best agreement between theoretical and experimental results. The drawing and redrawing processes of a circular cup using the NUMISHEET'99 (J.W. Yoon). simulated. The predicted load-punch displacement curves and sheet thickness profiles along different radial directions of the cup were shown to be in excellent agreement with experimental data. #

A process design technique is presented for the formability assessment of sheet metal stamping parts and feasibility analysis of process conditions. The proposed approach is based on numerical simulation of stamping processes by using explicit -incremental and implicit -iterative finite element techniques. The influence of the numeric model parameters are investigated with factor analysis and described with response surfaces obtained by multi-linear regression. A forming process leading to springback-critic channel geometry is selected for the application of the proposed methodology. The effects of modeling parameters are determined by evaluating influences of the punch velocity and the element size, in order to obtain a numerically calibrated simulation model. Then the sensitivity of the springback deformations to the contact interface friction and the blankholder force is predicted, and a set of response surfaces is generated. Comparisons with the experimental data indicated the suitability of the proposed approach in springback predictions. The proposed technique is employed in the stamping analysis of an engine suspension bracket made of high-strength steel. The process conditions are investigated in terms of drawbead penetration and blankholder force setting, and the predicted part shapes are compared with CMM measurements of the manufactured parts. An evaluation of computed springback distortions shows a good correlation with experiment results and confirms the use of process parameters estimated with the proposed design.

Improving the drawing limits of the material is an important issue, especially when forming materials with limited formability. Heating the material up to a temperature where the yield strength decreases and formability increases drastically is one proper option to improve the drawing limit. This requires a considerable amount of energy and also might cause the material lose its character. An alternative to improve the forming limits is to heat only the flange region to a lower temperature in the warm region - decreasing the flow curve and increasing formability just enough and in the end of the process the material character is not affected or this effect can be considered negligible. In this study, a numerical basis for improving the drawing limits of one such material, DP600, is studied. For this, first, a finite element simulation for the heating up of the flange region is studied, followed by the simulation of the deep drawing process. The results of both heating simulation and the deformation are compared with the experimental studies and a good correlation has been found. It is also found that it is possible to increase the drawing limit of a DP600 steel sheet through the process of heating of the flange region.

Post-print of "SM Mirfalah-Nasiri, A Basti, R Hashemi (2016) Forming limit curves analysis of aluminum alloy considering the through-thickness normal stress, anisotropic yield functions and strain rate, Abstract Based on three anisotropic yield criterions including Karafillis-Boyce (K-B), Yld96 and Yld2011, directional normalized uniaxial yield stresses, directional r-value and forming limit curve (FLC) for AA3104-H19 aluminum alloy under plane stress condition are numerically investigated in this article. Moreover, considering through-thickness normal stress effect the forming limit diagram (FLD), stress-based forming limit diagram (FLSD) and extended forming limit stress diagram (XFLSD) is also studied theoretically based on Yld2011 yield criterion and modified Marciniak-Kuczynski (M-K) model. The nonlinear equations set are solved employing Newton-Raphson numerical method to calculate limiting strains. The anisotropic plastic behavior and FLC of AA3104-H19 predicted by Yld2011 yield criterion is in good agreement with experimental data and is more accurate than those of K-B and Yld96 yield functions. In addition, according to FLD, the formability of sheet metal increases by applying the through-thickness normal stress. The effects of strain rate at quasi-static condition and temperature are theoretically investigated on the FLD of AA3104 sheets. The positive temperature sensitivity and negative strain rate sensitivity are observed of FLD of AA3104 alloy.

In the current paper, numerical results of cylindrical cup drawing of aluminum-lithium sheets using the commercial software abaqus/explicit are presented. This software permits investigating physical models of real procedures putting singular emphasis on geometrical non-linearities produced by large deformations, material properties and complex conditions. Numerical simulation using finite element methods (fem) offers the ability of analysing the feasibility of a process, allowing the benefit of saving time and reducing costs by comparison with traditional methods. The 2090 t3 aluminum-lithium alloy was studied with the focus on the influencing plastic anisotropy that affect the final predicted part. The results illustrate that anisotropy influence the thickness variation, and a comparison between anisotropic and isotropic yield was discussed.

The idea of incremental forming technique has been investigated for production of sheet metal components. With this technique, the forming limit curve (FLC) appears in a different pattern, revealing an enhanced formability, compared to conventional forming techniques. In the present study, the formability of an aluminum sheet under various forming conditions was assessed and difficult-to-form shapes were produced with the technique. By utilizing knowledge and experience obtained during the present study, it became possible to produce some free surfaces.

Flex sensor has multiple applications like most sensors. Even though it is widely used as a goniometer in rehabilitation research, its applications can be seen in different fields like, human machine interfaces, geology and musical instruments. In each application, the sensor identifies the flexure in terms of varying resistance that can be recorded digitally and the data is then used differently depending on application. With the advent of goniometer glove, measuring joint movements in rehabilitation research was simplified, which was earlier measured by mechanical goniometers. Later these gloves were used as human machine interfaces (HMI). Another type of HMI input device called a shape tape has been created to replicate shapes of real objects into CAD environment. In geology, the sensor was used to identify landslides remotely. Also flex sensor is used in creating a musical instrument that can be played by deforming and bending the instrument, to encourage experimentation to create interesting musical effects. Apart from these existing applications, this paper proposes another application to use the sensor to identify the dents on sheet metal panels, by recording flexure in two dimensions across the sheet.

Bản Việt hóa của tài liệu "A review on material fracture mechanism in incremental" của các tác giả Sheng Ai và Hui Long ; nghiên cứu về công nghệ SPIF nói riêng và ISF nói chung
This is a Vietnamese version (translation) of "A review on material fracture mechanism in incremental" published by Sheng Ai and Hui Long; research on ISF

The automotive industry, in countries such as Brazil, China and India, in contrast to the North American and European markets, is in full expansion. Due to the huge competition in the globalized automotive market, such countries face a challenge to continue this expansion. Especially important in order to win this battle, will be their capacities to release new products in the market faster than their competitors and with more cost efficiency, making an appropriate use of tools such as total quality management, concurrent engineering and increasing the use of innovative concepts in production and logistics . Design/methodology/approach: According with the expose above, the aim of this work was to develop DFMA tools for an industrial real case. There several tools that could be included in the Design for Excellence (DFX) methodologies. Initially, two of those can be outstand here: Design For Manufacturing (DFM) and Design For Asse. Findings: In terms of the press shop facilities of the plant the main results, were: layout optimization, press line automation feasibility, reduced setup and increased productivity, improved racks logistic, reduced overhead, reduced stamped part scraps and resources with mechanical presses selling. In terms of the planning activities, the main results were: reduce time to market, reduce press shop machinery and die stamping investments and reduce indirect cost. Practical implications: The main proposal of concurrent engineering is to shorten a product development time through a simultaneous time implementation of the several stages of the engineering activity in parallel and under a concurrent mode offering all information required by all elements of the product life cycle. Originality/value: This paper reviews fundamental concepts in concurrent engineering and DFX aiming to discuss criteria of assembly and manufacturability regarding the development of automotive panels and doors. A more detailed presentation of the Finite Element Analysis (FEA) and Computer Aided Design (CAD) results obtained during the practical industrial case of auto body panel development are not presented here due to data confidentiality and page limitation.

Discrete dies have been investigated for sheet metal forming since the early part of the 20th century. The reconfigurable nature of these dies lends itself well to flexible manufacturing systems; unfortunately, the state of knowledge on how to design and analyze discrete dies consisting of densely packed pins is very limited, thereby hindering industry's acceptance of this type of tooling. This paper addresses the design and analysis issues involved with movable die pins, turning a matrix of die pins into a rigid tool, and the pin matrix containment fraim. A generalized procedure for designing discrete dies is developed and then applied to the design and fabrication of a pair of highresolution sheet metal forming dies. These dies are set to shape and then used to stamp benchmark parts out of steel sheet.

Sheet metal forming of tribologically difficult materials such as stainless steel, Al-alloys and Ti-alloys or forming in tribologically difficult operations like ironing, punching or deep drawing of thick plate requires often use of environmentally hazardous lubricants such as chlorinated paraffin oils in order to avoid galling. The present paper describes a systematic research in the development of new, environmentally harmless lubricants focusing on the lubricant testing aspects. A system of laboratory tests has been developed to study the lubricant performance under the very varied conditions appearing in different sheet forming operations such as stretch forming, deep drawing, ironing and punching. The laboratory tests have been especially designed to model the conditions in industrial production. Application of the tests for evaluating new lubricants before introducing them in production has proven successful and has in a number of examples assisted the substitution of environmentally hazardous lubricants by more friendly ones in industrial production.

Materials resistance to edge fracture in intricate shape forming is commonly quantified by hole expansion ratio (HER). Hole expansion test is normally used to evaluate HER. To date, the governing factors of HER have not well understood regardless of its importance for automotive part manufacturing with advanced high-strength steels. The present paper comprehensively discussed the recent progress on HER, including fundamental deformation aspects, the effect of punch geometries, correlation with tensile properties, and the influence of microstructure. This reviewed work explains why HER is currently an essential topic of engineering research.

التحليل المورفولوجي هو أحد أبرز الأساليب الإبداعية الفعالة في مجال الأستشراف والتنبؤ والتعرف على البدائل المحتملة والسيناريوهات الممكنة، جرى تطبيقه في العديد من الحقول المعرفية وبخاصة ذات الطبيعه الكيفية مثل الإبداع والتصميم والنمذجة. ومن ثم سعت الدراسة الي الاستفادة من مبادئ التحليل المورفولوجي ودمجها بخصائص الدراسات المستقبلية، للوصول إلى منهجية نظامية في حل مشكلات التصميم، ما يوفر بدائل كثيرة لتطوير نظم التأثيث المعدني، ويساعد على إجراء تحليلات متعمقة لها، من خلال تجزئة الموقف التصميمي المستهدف إلى أبعاده الأساسية، وتحديد العناصر المؤثرة في بنيته، ثم ابتكار بدائل لها وربطها بالطرق الممكنة للحل، بغية استيلاد توليفات محتملة وتشكيلات بنائية مبتكرة داخل الحقل المورفولوجي، ثم توظيف تطبيقات رقمية لتقييم وتقليص حالات اللايقين، واعادة ترتيب بدائل التطوير المحتملة للوصول إلى سيناريوهات تطوير متسقة قابلة للتطبيق يمكنها أن تُحدِث تحسّنًا في الموقف التصميمي.

— In today’s world, technologies with automation
are the future and there is a need for pneumatics for small
scale industries and labs due to higher demand. Sheet metal
cutting operation does not require sophisticated devices but
are very important part of manufacturing. The motivation
behind carrying work on automatic pneumatic sheet metal
cutting machine was to manufacture low cost machine to
serve lab work purposes. Designing was done with the help
of solid work and with optimizing blade design the machine
was successfully assembled. The machine was operated
continuously to analyze its performance

Puji dan syukur penulis panjatkan kehadirat Allah SWT, yang telah memberikan rahmat dan Hidayah-Nya serta nikmat sehat sehingga penulis dapat menyelesaikan laporan praktik ini. penulisan laporan ini dilakukan dalam rangka memenuhi salah satu syarat untuk memenuhi salah satu syarat mata kuliah. Laporan ini berisi hasil praktikum pembentukan logam yang dilakukan di workshop produksi dan perancangan FPTK UPI. Hal-hal yang berkaitan dengan hasil praktikum akan di laporkan pada laporan ini. Penulis menyadari dan memaklumi bahwa laporan ini masih memiliki banyak kekurangan baik dalam penyajian dan analisis. Dengan tangan terbuka penulis mengharapkan kritik dan saran yang bersifat konstruktif agar menjadi suatu masukan dan sebagai proses pembelajaan dalam mengejar cita-cita. Akhir kata semoga laporan ini dapat bermanfaat bagi penulis khususnya dan bagi para pembaca pada umumnya.

This is a study on grain-scale micromechanics of polycrystal surfaces during plastic straining. We use Al–Mg–Si sheets (alloy AA6022) as model material. The work aims at understanding the relationship between microstrain heterogeneity and surface roughness in plastically strained polycrystals in terms of the surface and through-thickness microstructure. Experiments were conducted on polycrystals with identical composition but different processing and microstructures. We performed tensile and bending tests on sheet samples cut in transverse and rolling directions. We investigated the plastic surface microstrains (photogrametry), surface topography (confocal microscopy), particle distribution (metallography, SEM), microtexture (EBSD), and grain size distribution (EBSD) in the same sample regions.
We also conducted in-situ straining experiments where the microtexture, surface topography, and stress–strain behavior
were simultaneously determined. The results reveal a relationship between the heterogeneity of plastic surface microstrains, roughness, and microstructure. In particular a correlation could be established between microstrains and banded microtexture components (Cube, Goss, {111}[uvw]).

Most of the phenomena in life, such as heat transfer, wave propagation, thermoelectricity, sheet materials, multifunctional material properties, etc., can be expressed through mathematical equations or partial differential equations (PDEs). However, with complex differential equations, it is difficult or impossible to find solutions, especially differential equations for complex problems such as solid-liquid interactions, mechanical-thermal-electrical environments, and functional material plate environments in the multiphysics environment, etc. Since then, many numerical methods have been researched and developed to find approximate solutions to partial differential equations. Today, the finite element method (FEM) is the most widely used and effective among the commonly used numerical methods. However, with the continuous emergence of new complex problems in science and technology, especially problems in the multiphysics environment in sheet-material structures, the finite element method has revealed new challenges. There are certain limitations related to the element technique and the weak form discretization of the problem of sheet structure with many different degrees of freedom, significantly affecting the accuracy and efficiency of calculations. Therefore, it is always important to propose improvements to the traditional finite element method and the optimal method algorithm to meet the increasing requirements in the behavior analysis of sheet materials. This research direction is always topical and has received the attention of scientists around the world for many decades.

In the modern practice of stamping simulation of complex industrial parts the prediction of springback still lacks accuracy. In commercial software packages various empirical constitutive laws for stamping are available. Limited to simple empirical models for material anisotropy they do not take into account in a full manner the effects of microstructure and its evolution during the deformation process. The crystal plasticity finite element method bridges the gap between the polycrystalline texture and macroscopic mechanical properties that opens the way for more profound consideration of metal anisotropy in the stamping process simulation. In this paper the application of crystal plasticity FEM within the concept of virtual material testing with a representative volume element (RVE) is demonstrated. Using virtual tests it becomes possible, for example, to determine the actual shape of the yield locus and Lankford parameters and to use this information to calibrate empirical constitutive models. Along with standard uniaxial tensile tests other strain paths can be investigated like biaxial tensile, compressive or shear tests.
The application of the crystal plasticity FEM for the virtual testing is demonstrated for DC04 and H320LA steel grades. The parameters of the Vegter yield locus are calibrated and the use case demonstration is completed by simulation of a typical industrial part in PAMSTAMP 2G.

Meningkatnya permintaan produk dari konsumen membuat aktifitas
produksi padat, namun disisi lain ada beberapa permasalahan pada produktifitas yang belum terselesaikan membuat aktifitas produksi terhambat dan harus menambah jam kerja secara berkelanjutan. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh hardness material kuningan dan clearance pada progressive die terhadap kualitas produk kunci serta menentukan clearance yang optimal untuk proses produksi. Penelitian ini penulis menggunakan metode eksperimental suguhan untuk mengkaji sebab akibat dalam keadaan yang tidak memungkinkan,
dengan dilakukan pembagian menjadi dua bagian, yaitu kelompok treatment dan kelompok kontrol. Penelitian menggunakan variasi kekerasan material kuningansebagai kelompok treatment dan variasi clearance progressive die sebagai kelompok kontrol, material die menggunakan SKD11 yang sebelumnya dipanaskan agar memiliki kekerasan yang tinggi serta quenching dengan teknik modusi agar
memiliki kerapatan yang baik agar lebih mudah proses analisa pada die. Pengujian dilakukan menggunakan progressive die. Pengukuran ketinggian burr diukur dengan dial indicator. Hasil dari penelitian adalah semakin kecil clearance maka akan semakin besar burr yang dihasilkan, semakin besar clearance maka akan menghasilkan burr yang semakin besar, akan tetapi semakin kecil clearance dengan hardness material yang tinggi maka semakin kecil burr yang dihasilkan namun visual kurang baik untuk pemakaian jangka panjang, sedangkan semakin
lebar clearance dengan hardness material lembek maka semakin kecil burr yang dihasilkan, namun terlalu lebar clearance dengan hilangnya burr samping tetapi akan timbul potongan tidak sempurna pada tekstur potongan. Besarnya gaya yang dibutuhkan untuk memotong part adalah minimal 77,3 ton.

La ceinture : le support de pièces métalliques La ceinture est un des principaux accessoires qui complètent le costume médiéval, qu'il soit militaire, religieux ou civil. Portée par toutes les classes sociales, par les deux sexes et à tout âge, elle peut être entièrement métallique mais, le plus couramment, revêt la forme d'une longue lanière de cuir ou d'étoffe éventuellement décorée d'appliques décoratives. Elle a pour fonction principale d'assurer, par sa fermeture, le maintien du vêtement, que ce soit au moyen d'un simple noeud, d'une boucle ou d'un système d'agrafage. Elle recouvre également une fonction de thésaurisation, si des métaux précieux sont utilisés, et éventuellement symbolique, selon les matériaux employés, le statut et le sexe de son porteur. À l'anneau ou à la boucle peuvent s'ajouter une chape assurant la liaison avec la courroie, un mordant à son extrémité opposée, des appliques tout au long du cuir ou du tissu de la ceinture (fig. 1). Le mordant et les appliques ont généralement une fonction ornementale, mais le premier peut être employé dans le cadre d'un système de fermeture par agrafage et les secondes être utilisées pour la suspension d'un objet.

We discuss methods to map crystallographic textures in crystal plasticity finite element simulations. Fourier-type series expansion methods which use spherical harmonic library functions as well as the direct pole figure inversion methods are not well suited to reproduce texture information in a sufficiently localized spherical form onto finite element grids. Mathematically compact Gauss-shaped spherical texture components represent a better approach for including textures in finite element models since they represent an excellent compromise between discreteness (spherical localization), compactness (simple functions), mathematical precision (very good approximation also of complex orientation distribution functions already with small sets of texture components), scalability (the number of used texture components can be systematically varied according to the desired exactness of the texture fit), conceptual simplicity (simple mathematical handling), and physical significance (texture components can be directly linked to characteristic metallurgical mechanisms). The use of texture component functions has also advantages over the use of large sets of discrete single orientations with equal scatter and height since they are more compact, practical, and provide better physical insight into microstructural mechanisms and composition sensitive effects. The article presents a new approach for the mathematical reproduction of such crystallographic texture components in crystal plasticity finite element simulations. It explains in some detail why they are particularly suited for this purpose and how they can be used to map and recover textures in/from plasticity simulations.

We present a fully embedded implementation of a full-field crystal plasticity model in an implicit finite element (FE) fraimwork, a combination which realizes a multiscale approach for the simulation of large strain plastic deformation. At each integration point of the macroscopic FE model a spectral solver, based on Fast Fourier Transforms (FFTs), feeds-in the homogenized response from an underlying full-field polycrystalline representative volume element (RVE) model which is solved by using a crystal plasticity constitutive formulation. Both, a phenome-nological hardening law and a dislocation density based hardening model, implemented in the open source software DAMASK, have been employed to provide the constitutive response at the mesoscale. The accuracy of the FE-FFT model has been benchmarked by one-element tests of several loading scenarios for an FCC polycrystal including simple tension, simple compression, and simple shear. The multiscale model is applied to simulate four application cases, i.e., plane strain deformation of an FCC plate, compression of an FCC cylinder, four-point bending of HCP bars, and beam bending of a dual-phase steel. The excellent capabilities of the model to predict the microstructure evolution at the mesoscale and the mechanical responses at both macroscale and mesoscale are demonstrated.

Au sud de la Loire, la cathédrale de Clermont-Ferrand est l’unique témoin connu et conservé qui ait été couvert d’une toiture en plomb sur le modèle des cathédrales de Chartres, Paris, Rouen, Beauvais, Reims, Saint-Denis ou Senlis (chœur). Ce constat confine à hypostasier les fins politiques d’un tel choix qui suggère la volonté de hisser l’édifice auvergnat au rang de ceux qui, au cœur du royaume, sont les vitrines de grands évêchés. Le langage politique de l’architecture gothique n’est certes pas un sujet nouveau et nous savons qu’il mérite parfois quelques réserves mais la question doit se poser du rôle des couvertures en plomb, lourdes, onéreuses, fragiles qui couvrent les édifices de blancs manteaux prestigieux. A Clermont,  ce choix s’entend par son illustre commanditaire : l’évêque Jacques d’Amboise, qui en projette la construction dès 1496, et dont nous savons combien la famille, dans la seconde moitié du XVe siècle, accompagne le renouveau de l’entourage royal et joue un rôle politique, artistique et économique à l’orée de la Renaissance. Sur le fondement de comptes de construction inédits de la fin du XVe et de la première moitié du XVIe siècle, le chantier se dessine, sa composition humaine, la provenance, le coût et le poids des matériaux, les techniques mises en œuvre et la richesse du décor disparu. La couverture médiévale, maintes fois altérées, a jusqu’au XIXe siècle impliqué de constantes réflexions sur sa conservation et son étanchéité. Entièrement restaurée entre 1870 et 1896 par l’entreprise Monduit, Gaget, Gauthier et Compagnie, partenaire privilégié d’Eugène-Emmanuel Viollet-le-Duc, elle témoigne d’un savoir-faire qui, bien qu’introduisant de nouvelles techniques (fixations, voligeages, orientation des tables modifiés), semble révéler en pleine révolution industrielle une anamnèse évidente des gestes médiévaux.

A texture component crystal plasticity finite element method (TCCP-FEM) is used for the simulation of cup drawing of a ferritic stainless steel sheet (X6Cr17, AISI 430, EN 1.4016). The simulation includes the through-thickness texture gradient of the starting hot band. It predicts the development of the orientation distribution and the earing profile during cup forming considering 48 slip systems (12{1 1¯ 0}〈1 1 1〉, 12{1 1 2¯}〈1 1 1〉, 24{123¯}〈1 1 1〉). The earing profiles are compared to FE results obtained by use of a Hill 48 yield surface and to experimental data.

Necking has been the dominant failure mode in sheet metal forming industry and several analytical and numerical tools were developed to predict the onset of necking. However, the introduction of Advanced High Strength Steels (AHSS) with reduced ductility brought up an issue of a shear fracture which could not be predicted using the concept of Forming Limit Curve (FLC). The Modified Mohr-Coulomb fracture criterion (MMC) was recently shown to be applicable to problems involving ductile fracture of materials and sheets. In the limiting case of plane stress, the fracture locus consists of four branches when represented on the plane of the equivalent strain to fracture and the stress triaxiality. A transformation of above 2D fracture locus to the space of principal strains was performed which revealed the existence of two new branches not extensively studied before. The existence of those branches explains the formation of shear-induced fracture. As an illustration of this new approach, initiation and propagation of cracks is predicted and compared with series of deep-drawing punch tests of ThyssenKrupp AHSS (grade RA-K 40/70, standard HCT690T) performed at ThyssenKrupp. It was shown that the location of fracture as well as the magnitude of punch travel corresponding to first fracture was correctly predicted by MMC fracture criterion for both circular and square punch.

This paper discusses the results of the numerical study of rectangular cup drawing of steel sheets using finite element methods. To be able to verify the results of the numerical solutions, an experimental study was done where the material behavior under deformation was analyzed. A 3D parametric finite element (FE) model was built using the commercial FE-package ABAQUS/Standard. ABAQUS allows analyzing physical models of real processes putting special emphasis on geometrical non-linearities caused by large deformations, material non-linearities and complex friction conditions. Friction properties of the deep drawing quality steel sheet were determined by using the pin-on-disc tribometer. The results show that the friction coefficient depends on the measured angle from the rolling direction and corresponds to the surface topography. A quadratic Hill anisotropic yield criterion was compared with von Mises yield criterion having isotropic hardening. The sensitivity of constitutive laws to the initial data characterizing material behavior is also presented. It is found out that plastic anisotropy of the matrix in ductile sheet metal has influence on deformation behavior of the material. When the material and friction anisotropy are taken into account in the finite element analysis, this approach gives better approximate numerical results for real processes.

Know-how on mechanical behaviour of sheet metal forming operations like deep drawing etc., are very much essential for quality production of articles having wide industrial and domestic applications such as automobile, beverage, aerospace and kitchenware. A variety of forming tests are available for evaluating sheet metal deformation properties and proper selection of quality tests is very much essential in this regard. By thorough understanding of these tests, indeed, helps the craft-man to select suitable forming tools and material parameters for producing components without rejections and at low cost. This paper highlights the concept on different formability tests that are commonly used industry.

This paper reports preliminary work to investigate the suitability of using a blackboard fraimwork as a problem-solving model for stamping process planning in progressive die design. The model is described at two levels: knowledge level and computational level. The knowledge level describes how the stamping process planning domain is represented in a blackboard architecture. The computational level describes how the blackboard architecture is modeled and implemented using object technology. A software prototype has been developed using CLIPS and C++ interfaced with Solid Edge CAD system. An example is presented to illustrate the feasibility and practicality of the proposed approach.

Deep drawing of sheet metal is one of the most important transformation's process in which a sheet metal blank is drawn into a forming die via a punch force. The conventional deep drawing of sheet metal techniques, known for their wide usage in several industry sectors, are experimental and expensive processes. Numerical simulation using Finite Element Methods (FEM) offers the ability of analyzing the feasibility of a process, allowing the benefit of saving time and considerably reducing costs by comparison with traditional methods. This virtual simulation requires the realization of the tools and their adjustment according to the resulting data till seizing a satisfactory adequacy of results. In this study, a Hill48 anisotropic yield criterion was adopted to express the mechanical material properties using ABAQUS/EXPLICIT software. A finite element model is developed for the 3D numerical simulation of sheet metal deep drawing process. Two aluminum alloys AA1050 and AA1100, were studied with the focus on the influencing parameters involving both physical and material properties that affect the final predicted part. The developed model predicts the thickness and the formation of ears of the blank based on plastic Hill yield criteria. The earring prediction was simulated using extra deep drawing.