Papers by Keyword: Elasto-Plastic Deformation

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Authors: F. Song, Yi Sun, Dongpo Wang
Authors: L. Roslan, Tetsuya Ohashi, Yohei Yasuda, Chikara Suruga
Abstract: Elasto-plastic tensile deformations in multi-colony structures are studied by finite element analyses to investigate how the deformation in multi-colony structures influence the strain concentration around colony boundary. The results obtained from plastic strain distributions show that plastic strain concentrates around colony boundary when there is a large difference of deformation between adjacent colonies and around the point where boundaries of differently aligned colonies meet.
Authors: Hiroyuki Muto, Mototsugu Sakai
Abstract: A novel indentation method is proposed to study the mechanical properties of porous and/or heterogeneous materials by the use of a cylindrical indenter with line loading on test specimens. The problems in line contact are examined. The indentation load P versus penetration depth h relation in line contact is expressed in terms of the radius R of cylindrical indenter and the contact length L. An application of a cylindrical indentation to a polycrystalline graphite leads to a successful determination of the Young's modulus and the yielding strength. It is concluded that the line contact rather than the conventional pyramidal point contact is more efficient for the experimental deternination of mechanical properties of porous and/or heterogeneous materials.
Authors: Roslan Lidyana, Tetsuya Ohashi, Yohei Yasuda, Kohsuke Takahashi, Chikara Suruga
Abstract: Elasto-plastic tensile deformations in pearlite lamellar and two-colony structures are studied by finite element analyses to investigate the effects of lamellar thickness ratio and difference of lamellae orientation of two colonies in pearlite microstructure. The results obtained from plastic strain distributions in lamellar and colony structures show that plastic deformation in cementite lamellar stabilized when ferrite lamellar is thicker than cementite lamellar thickness and plastic strain concentrates when the difference between cementite lamellar orientation in two colonies are larger than 45°.
Authors: Jyoti Kumar Doley, Sachin D. Kore
Abstract: Electromagnetic forming (EMF) is a typical high speed forming process using the energy density of a pulsed magnetic field to form work pieces made of metals with high electrical conductivity like aluminum. In view of new lightweight constructions, special forming processes like EMF gain importance for the associated materials. In this paper modeling of electromagnetic sheet metal forming process is carried out by using commercial finite element software LS-DYNA®. A fully coupled numerical simulation method has been incorporated to study the interaction of the electromagnetic field and the structural deformation via transient analysis. Studies on the effect of first current pulse in electromagnetic forming are reported in the paper.
Authors: Sebastian Wroński, Andrzej Baczmanski, Anita Gaj, Krzysztof Wierzbanowski, Michael E. Fitzpatrick, Vincent Klosek, Alain Lodini, Marianna Marciszko
Abstract: The aim of the present work is to study effects occurring during elatoplastic deformation and unloading of Al/SiCp metal–matrix composite material. We have measured lattice strains for both phases independently using two separated diffraction peaks (the 111 reflections of Al and SiC) during in situ tensile testing. Lattice strains were measured in the direction parallel to the applied load. The results were compared with an elastoplastic model in order to find parameters determining the plastic deformation of Al matrix (critical resolved shear stress and hardening parameter). We have found that during initial deformation relaxation of the thermal stresses occurs in both phases. Afterwards, the distribution of strains measured during the in situ test and unloading of the sample agree very well with self-consistent model prediction.
Authors: Shinichi Enoki, Yuki Shibayama, Mitsuru Saito, Junichi Ito, Yasunori Nakamura, Tomiso Ohata
Abstract: Suspended ceilings consist of ceiling boards, furring channels, channel clips, furring brackets, hangers and ceiling bolts. The ceilings are easy to drop down when the large earthquake occurred. The channel clips deform and disengage from the ceilings or break at that time. Design engineers calculate and evaluate the stress in the clips by using method with mechanics of materials. The evaluation depends on the experiences of the engineers. Mechanics of materials is considered in elastic region, but the channel clips are in plastic deformation. Therefore, after the design, the clips are manufactured and are subjected to verification tests as the design evaluation. Sometimes the prototype tests become multiple times. The purpose of this research is to build a simple method of an efficient design for the channel clips. It is ordinary to use elastic-plastic analysis at strength design in the case of plastic deformation. But software for elastic-plastic analysis is expensive, so the design method of the channel clips depends on the elastic stress analysis function of 3D CAD in this research. Instead, we designed and evaluated the equivalent stress corresponding the tensile strength in plastic deformation as the evaluation criterion. As a result, it was possible to evaluate the design that the channel clips are not broken when assuming earthquake occurrence with a seismic intensity of 7. This evaluation is reliable compared to the verification test conducted in the past.
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