Dynamic Fracture Behavior of 316L Brazed Joint: Study With Experimental and Finite Element Methods

2018 ◽  
Author(s):  
Weiya Zhang ◽  
Wenchun Jiang ◽  
Bin Yang ◽  
Ming Song ◽  
Xiangnan Zhai
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Strain Rate ◽  
Dynamic Fracture ◽  
Fracture Behavior ◽  
Dynamic Pressure ◽  
Brazed Joints ◽  
Brazed Joint ◽  
Axial Fracture ◽  
Element Method

Brazed joints are widely used in the plate fin structures, and it is very important to ensure the strength under dynamic pressure. This paper investigated the dynamic fracture mechanism of 316L brazed joints using experimental and finite element method. Results show that the yield strength, tensile strength and elongation of the brazed joint are closely related with the strain rate. Using the finite element method, the strain rate sensitive model (Johnson-Cook) is built, and the brazed joint shows a multi-axial fracture mode. Meanwhile, the brazed residual stress and filler metal thickness affect the dynamic fracture behavior of the brazed joint.

Fracture Mechanics of Architecture Dependent Fracture in Trabecular Bone Using the Cohesive Finite Element Method

2007 ◽  
Author(s):  
Vikas Tomar
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Trabecular Bone ◽  
Fracture Behavior ◽  
Bone Microstructure ◽  
Tissue Properties ◽  
Rate Dependent ◽  
Microdamage Accumulation ◽  
Element Method ◽  
Rate Of Loading

Trabecular bone fracture is closely related to the trabecular architecture and microdamage accumulation. Micro-finite element models have been used to investigate the elastic and yield properties of trabecular bone but have only seen limited application in modeling the microstructure dependent fracture of trabecular bone, [1, 2]. In the presented research a cohesive finite element method (CFEM) based approach that can be used to model microstructure and loading rate dependent fracture in trabecular bone is developed for the first time. The emphasis is on understanding the effect of the rate of loading and its correlation with the bone microstructure on the microdamage accumulation and fracture behavior in the trabecular bone. Analyses focus on understanding the effect of the rate of loading, change in bone tissue properties with aging, and their correlation with the bone microstructure on the microdamage accumulation and the fracture behavior in the trabecular bone.

Analyses of Axisymmetric Sheet Forming Processes by Rigid-Viscoplastic Finite Element Method

1987 ◽  
Vol 109 (4) ◽  
pp. 347-354 ◽  
Author(s):  
J. J. Park ◽  
S. I. Oh ◽  
T. Altan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Strain Rate ◽  
Rate Sensitivity ◽  
Sheet Forming ◽  
Flow Rule ◽  
Pressure Curve ◽  
Analytical Prediction ◽  
Key Factor ◽  
Element Method

Two types of sheet forming processes are analyzed by rigid-viscoplastic FEM (Finite Element Method): axisymmetric punch stretching and hydrostatic bulge forming. The present formulations, based on the membrane theory and the Hill’s anisotropic flow rule, include the rate sensitivity which is a key factor in controlling the forming of superplastic materials. Normal anisotropy is taken into account and Coulomb friction is assumed at the interface between punch and sheet. Nonsteady-state deformation processes, investigated in this study, were quasi-statically and incrementally analyzed. An FEM code was developed, using two-node linear elements with two degrees of freedom at each node, and applied to solve four categories of problems: (1) A.K. steel punch stretching, (2) hydrostatic bulging of a rate-insensitive material, (3) hydrostatic bulging of rate-sensitive materials, and (4) hydrostatic bulging of a superplastic material (Ti-6-4). Strain distributions and shape changes predicted in the first two problems were compared with experiments and results of other analyses. The results of the third problem could not be compared with experiments; however, the results showed that the rate sensitivity affects the deformation as expected. The fourth problem is the main theme of this paper. To maintain the superplasticity in forming processes and to produce sound products, the control of the strain-rate is a key factor. A hydrostatic bulge forming process, which is often used for manufacturing structural aerospace parts, was analyzed and discussed. Further, an optimum pressure curve (pressure versus time), which maintains the desired strain-rate in the deformed material, was obtained and compared with the results of an analytical prediction, available in the literature.

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