Modeling and simulation of three-dimensional extrusion swelling of viscoelastic fluids with PTT, Giesekus and FENE-P constitutive models

2013 ◽  
Vol 72 (8) ◽  
pp. 846-863 ◽  
Author(s):  
Yue Mu ◽  
Guoqun Zhao ◽  
Anbiao Chen ◽  
Xianghong Wu
Author(s):  
T. D. Marusich ◽  
S. Usui ◽  
R. Aphale ◽  
N. Saini ◽  
R. Li ◽  
...  

The three dimensional (3D) finite element modeling (FEM) and experimental validation of drilling are presented. The Third Wave AdvantEdge machining simulation software is applied for the FEM. It includes fully adaptive unstructured mesh generation, thermo-mechanically coupling, deformable tool-chip-workpiece contact, interfacial heat transfer across the tool-chip boundary, and constitutive models appropriate for process conditions and finite deformation analyses. The workpiece is modeled with a predrilled cone-shape blind hole to enable the early full-engagement of the whole drill point region to reduce the simulation time. Drilling experiments are conducted on the Ti-6Al-4V using a twist drill geometry. The calculated cutting force and torque are compared with the results of experiments with good agreement. Effects of process parameters on the stress and temperature distributions of the drill and workpiece are investigated in detail using the FEM.


Author(s):  
David M. Pierce ◽  
Thomas E. Fastl ◽  
Hannah Weisbecker ◽  
Gerhard A. Holzapfel ◽  
Borja Rodriguez-Vila ◽  
...  

Through progress in medical imaging, image analysis and finite element (FE) meshing tools it is now possible to extract patient-specific geometries from medical images of, e.g., abdominal aortic aneurysms (AAAs), and thus to study clinically relevant problems via FE simulations. Medical imaging is most often performed in vivo, and hence the reconstructed model geometry in the problem of interest will represent the in vivo state, e.g., the AAA at physiological blood pressure. However, classical continuum mechanics and FE methods assume that constitutive models and the corresponding simulations start from an unloaded, stress-free reference condition.


2012 ◽  
Vol 11 (5) ◽  
pp. 1525-1546 ◽  
Author(s):  
Philip Barton ◽  
Evgeniy Romenski

AbstractIn this paper we show that entropy can be used within a functional for the stress relaxation time of solid materials to parametrise finite viscoplastic strain-hardening deformations. Through doing so the classical empirical recovery of a suitable irreversible scalar measure of work-hardening from the three-dimensional state parameters is avoided. The success of the proposed approach centres on determination of a rate-independent relation between plastic strain and entropy, which is found to be suitably simplistic such to not add any significant complexity to the final model. The result is sufficiently general to be used in combination with existing constitutive models for inelastic deformations parametrised by one-dimensional plastic strain provided the constitutive models are thermodynamically consistent. Here a model for the tangential stress relaxation time based upon established dislocation mechanics theory is calibrated for OFHC copper and subsequently integrated within a two-dimensional moving-mesh scheme. We address some of the numerical challenges that are faced in order to ensure successful implementation of the proposedmodel within a hydrocode. The approach is demonstrated through simulations of flyer-plate and cylinder impacts.


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