Propagation and Opening of a Through Crack in a Pipe Subject to Combined Cyclic Thermomechanical Loading

1976 ◽  
Vol 98 (1) ◽  
pp. 17-25 ◽  
Author(s):  
T. R. Hsu ◽  
A. W. M. Bertels
Keyword(s):  
Bauschinger Effect ◽  
Thermal Loading ◽  
Thin Wall ◽  
Pipe Material ◽  
Displacement Fields ◽  
Stress And Displacement Fields ◽  
Growing Crack ◽  
Cyclic Plastic Deformation ◽  
Cyclic Thermomechanical Loading ◽  
Thermoelastic Plastic

The present investigation deals with the propagation and opening of a single crack in a thin wall pipe subject to cyclic pressure and thermal loading. A thermoelastic-plastic analysis based on the finite element variational technique is used to calculate the stress and displacement fields in the vicinity of the growing crack. A special type of element known as a “breakable element” is developed to model the gradual propagation of the crack. Kinematic work hardening is included to account for the Bauschinger effect of the pipe material when subjected to cyclic plastic deformation.

A Stress Singularity Parameter Approach for Evaluating the Interfacial Reliability of Plastic Encapsulated LSI Devices

1989 ◽  
Vol 111 (4) ◽  
pp. 243-248 ◽  
Author(s):  
T. Hattori ◽  
S. Sakata ◽  
G. Murakami
Keyword(s):  
Adhesive Strength ◽  
Evaluation Method ◽  
Stress Singularity ◽  
The Finite Element Method ◽  
Displacement Fields ◽  
Stress And Displacement Fields ◽  
Ni Alloy ◽  
Base Resin ◽  
Interfacial Reliability ◽  
Parameter Approach

Since the stress and displacement fields near a bonding edge show singularity behaviors, the adhesive strength evaluation method, using maximum stresses calculated by a numerical stress analysis such as the finite element method, is generally not valid. In this paper, a new method, which uses two stress singularity parameters, is presented for evaluating adhesive strength. This method is applied to several kinds of molded models, composed of epoxy base resin and Fe-Ni alloy sheets, and plastic encapsulated LSI models. Predictions about the initiation and extension of delamination are compared with the results of observations made by scanning acoustic tomography on these models.

Micro-Mechanical Deformation Analysis of Surface Laminar Circuit in Organic Flip-Chip Package: An Experimental Study

2000 ◽  
Vol 122 (4) ◽  
pp. 294-300 ◽  
Author(s):  
B. Han ◽  
P. Kunthong
Keyword(s):  
Flip Chip ◽  
Thermal Loading ◽  
Region Of Interest ◽  
Deformation Analysis ◽  
High Modulus ◽  
Displacement Fields ◽  
Complex Deformation ◽  
Mechanical Deformations ◽  
Displacement Sensitivity ◽  
Package Reliability

Thermo-mechanical deformations of microstructures in a surface laminar circuit (SLC) substrate are quantified by microscopic moire´ interferometry. Two specimens are analyzed; a bare SLC substrate and a flip chip package assembly. The specimens are subjected to a uniform thermal loading of ΔT=−70°C and the microscopic displacement fields are documented at the identical region of interest. The nano-scale displacement sensitivity and the microscopic spatial resolution obtained from the experiments provide a faithful account of the complex deformation of the surface laminar layer and the embedded microstructures. The displacement fields are analyzed to produce the deformed configuration of the surface laminar layer and the strain distributions in the microstructures. The high modulus of underfill produces a strong coupling between the chip and the surface laminar layer, which produces a DNP-dependent shear deformation of the layer. The effect of the underfill on the deformation of the microstructures is investigated and its implications on the package reliability are discussed. [S1043-7398(00)01304-9]

Convergence Study on Application of the Over-Deterministic Method for Determination of Near-Tip Fields in a Cracked Plate Loaded in Mixed-Mode

2012 ◽  
Vol 249-250 ◽  
pp. 76-81 ◽  
Author(s):  
Lucie Šestáková ◽  
Václav Veselý
Keyword(s):  
Mixed Mode ◽  
Brittle Materials ◽  
Higher Order ◽  
Displacement Fields ◽  
Deterministic Method ◽  
Crack Behavior ◽  
Stress And Displacement Fields ◽  
Higher Order Terms ◽  
Convergence Study

Multi-parameter description of crack behavior in quasi-brittle materials offers still enough space for investigations. Several studies have been carried out by the authors in this field [1-3]. One part of the publications by the authors (this work included) contain analyses of the accuracy, convergence and/or tuning of the over-deterministic method that enables determination of the coefficients of the higher-order terms in Williams expansion approximating the stress and displacement fields in a cracked body without any complicated FE formulations. These intermediate studies should bring together a list of recommendations how to use the ODM as effectively as possible and obtain reliable enough values of coefficients of the higher-order terms. Thus, the stress/displacement field can be determined precisely even in a larger distance from the crack tip, which is crucial for assessment of the fracture occurring in quasi-brittle materials.

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