Finite versus small strain discrete dislocation analysis of cantilever bending of single crystals 
期刊名称Acta Mechanica Sinica
作者Nilgoon Irani; Joris J. C. Remmers; Vikram S. Deshpande
摘要Plastic size effects in single crystals are investigated by using finite strain and small strain discrete dislocation plasticity to analyse the response of cantilever beam specimens. Crystals with both one and two active slip systems are analysed, as well as specimens with different beam aspect ratios. Over the range of specimen sizes analysed here, the bending stress versus applied tip displacement response has a strong hardening plastic component. This hardening rate increases with decreasing specimen size. The hardening rates are slightly lower when the finite strain discrete dislocation plasticity (DDP) formulation is employed as curving of the slip planes is accounted for in the finite strain formulation. This relaxes the back-stresses in the dislocation pile-ups and thereby reduces the hardening rate. Our calculations show that in line with the pure bending case, the bending stress in cantilever bending displays a plastic size dependence. However, unlike pure bending, the bending flow strength of the larger aspect ratio cantilever beams is appreciably smaller. This is attributed to the fact that for the same applied bending stress, longer beams have lower shear forces acting upon them and this results in a lower density of statistically stored dislocations.
关键词Dislocations; Bending; Finite strain; Size effects
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作者地址1 Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD, Delft, The Netherlands;
2 Department of Mechanical Engineering, Eindhoven University of Technology, P. O. Box 513, 5600 MB, Eindhoven, The Netherlands;
3 Department of Engineering, Cambridge University, Trumpington Street, Cambridge CB2 1PZ, UK

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