scholarly journals Finite Element Simulation with Coupled Thermo-Mechanical Analysis of Superplastic Dieless Tube Drawing Considering Strain Rate Sensitivity

2009 ◽  
Vol 50 (1) ◽  
pp. 161-166 ◽  
Author(s):  
Tsuyoshi Furushima ◽  
Ken-ichi Manabe
2020 ◽  
Vol 0 (12) ◽  
pp. 10-16
Author(s):  
V.V. Avtaev ◽  
◽  
D. V. Grinevich ◽  
A. V. Zavodov

Yielding tests of VTI-4 alloy specimens have been carried out at temperature 1010 °C under conditions of high-speed loading. Based on the test results the modulus of elasticity as well as axial and radial residual deformation values in the end and central zones for each loading stage were determined. Fitting criteria for finite element simulation and the experiment are proposed with tracing VTI-4 alloy diagram deformation at temperature 1010 °C and strain rate of 2.5 sec–1. As a result of finite element simulation the relationship between the material structures obtained during high-speed yielding and the deflected modes in different zones was determined.


2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Liancun Zhang ◽  
Qiang Huang ◽  
Wenkang Wang ◽  
Kangjian Cai

Abstract This study provides a type of soft vacuum-actuated rotary actuator. The structures in the actuator are based on different elastomeric structures that comprise a number of interacting elastic radial beams, elastic circumferential beams, and interconnected, deformable sector ring structure air chambers. When negative pressure is applied to the structure, the radial beams bend reversibly into serpentine shapes until adjacent circumferential beams contact each other. This bending results in a large change in the circumferential angle of the structure, but a smaller change in its radial width. Thus, the structure produces rotational motion in its circumferential direction. The design, fabrication, and mechanical analysis of the actuator are introduced, respectively. Moreover, finite element simulation analysis and experimental testing are carried out to study the corresponding relations between the air pressure, rotation angle, and force of the actuator. In addition, the stimulation results and the experimental results of the actuator are statistically analyzed by statistical product and service solutions (spss) statistical software. The test results of the experimental platform are highly correlated with the results of the finite element simulation.


1992 ◽  
Vol 114 (4) ◽  
pp. 441-451 ◽  
Author(s):  
S. Brown ◽  
H. Song

Current simulations of welding distortion and residual stress have considered only the local weld zone. A large elastic structure surrounding a weld, however, can couple with the welding operation to produce a final weld state much different from that resulting when a smaller structure is welded. The effect of this coupling between structure and weld has the potential of dominating the final weld distortion and residual stress state. This paper employs both two-and three-dimensional finite element models of a circular cylinder and stiffening ring structure to investigate the interaction of a large structure on weld parameters such as weld gap clearance (fitup) and fixturing. The finite element simulation considers the full thermo-mechanical problem, uncoupling the thermal from the mechanical analysis. The thermal analysis uses temperature-dependent material properties, including latent heat and nonlinear heat convection and radiation boundary conditions. The mechanical analysis uses a thermal-elastic-plastic constitutive model and an element “birth” procedure to simulate the deposition of weld material. The effect of variations of weld gap clearance, fixture positions, and fixture types on residual stress states and distortion are examined. The results of these analyses indicate that this coupling effect with the surrounding structure should be included in numerical simulations of welding processes, and that full three-dimensional models are essential in predicting welding distortion. Elastic coupling with the surrounding structure, weld fitup, and fixturing are found to control residual stresses, creating substantial variations in highest principal and hydrostatic stresses in the weld region. The position and type of fixture are shown to be primary determinants of weld distortion.


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