Mapping mesh generation is widely applied in pre-processes of Finite Element Method (FEM). In this study, the basic 3D mapping equations by Lagrange interpolating function are founded. Based these equations, a mapping pattern library, which maps essential configurations e.g. line, circle, rotary body, sphere etc. to hexahedral FEM mesh, has been built. Then available FEM mesh will be generated by clipping and assembling the mapped essential objects. Study case illustrates that the proposed method is simple and efficient to generate valid FEM mesh for complex 3D engineering structure.
The combined effects of void size and void shape on the void growth are studied by using the classical spectrum method. An infinite solid containing an isolated prolate spheroidal void is considered to depict the void shape effect and the Fleck-Hutchinson phenomenological strain gradient plasticity theory is employed to capture the size effects. It is found that the combined effects of void size and void shape are mainly controlled by the remote stress triaxiality. Based on this, a new size-dependent void growth model similar to the Rice-Tracey model is proposed and an important conclusion about the size-dependent void growth is drawn: the growth rate of the void with radius smaller than a critical radius rc may be ignored. It is interesting that rc is a material constant independent of the initial void shape and the remote stress triaxiality.
Based on approximate theoretical analyses on atypieal spherical cell containing a sphericalmicrovoid,the influences of matrix materials’ microscopic scale on the macroscopic constitutive potential the-ory of porous material and microvoid growth have been investigated in detail.By assuming that the plastic de-formation behavior of matrix materials follows the strain gradient (SG) plastic theory involving the stretch androtation gradients,the ratio (λ=l/a) of the matrix materials’ intrinsic characteristic Length l to the micro-void radius a is introdnced into the plastic constitutive potential and the void grroth law.The present resultsindicate that,when the radius a of microvoids is comparable with the intrinsic characteristic length l of thematrix materials,the influence of microscopic size effect on neither the constitutive potential nor the micro-void evolution predicted can he ignored.And when the void radius a is much lager than the intrinsic charac-teristic length l of the matrix materials,the present model can retrogress automatically to the improved Gur-son model that takes into account the strain hardening effect of matrix materials.
Huang Minsheng Li Zhenhuan Wang Cheng Chen Chuanyao
