A Note on the Normalized Approach to Simulating Moisture Diffusion in a Multimaterial System Under Transient Thermal Conditions Using ansys 14 and 14.5

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Dapeng Liu ◽  
Seungbae Park
Keyword(s):  
Material Property ◽  
Thermal Conditions ◽  
Moisture Diffusion ◽  
Electronic Components ◽  
Current Version ◽  
Temperature Dependent ◽  
Moisture Concentration ◽  
Hygroscopic Swelling ◽  
Packaging Industry ◽  
Transient Thermal

Moisture can have significant effects on the performance and reliability of electronic components. Accurately simulating moisture diffusion is important for designers and manufacturers to obtain a realistic reliability evaluation. Beginning with version 14, ansys is capable of simulating diffusion and related behaviors, such as hygroscopic swelling, with newly developed elements. However, a normalized approach is still required to deal with the discontinuity of concentrations at the material boundaries, and normalization of the moisture concentration in transient thermal conditions is tricky. Case studies have shown that normalizing the moisture concentration with respect to a time- or temperature-dependent material property will lead to erroneous results. This paper re-addresses the issues of performing diffusion simulations under transient thermal conditions and more general anisothermal conditions (temporally and spatially), and suggests an easy-to-use approach to cope with the limitations of the current version for users in the electronic packaging industry.

SPH Analysis for Transient Thermal Stress of FGMs with Temperature-Dependent Properties

2015 ◽  
Vol 1096 ◽  
pp. 297-301
Author(s):  
Gui Ming Rong ◽  
Hiroyuki Kisu
Keyword(s):  
Thermal Stress ◽  
Thermal Conditions ◽  
Functionally Graded ◽  
Temperature Dependent ◽  
Graded Materials ◽  
Initial Stage ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Temperature Dependent Properties ◽  
Transient Thermal

A formulation using the deviatoric stress and the continuity equation is extended to the analysis of the dynamic response of functionally graded materials (FGMs) subjected to a thermal shock by smoothed particle hydrodynamics (SPH), in which temperature dependent properties of materials are considered. Several dynamic thermal stress problems are analyzed to investigate the fluctuation of thermal stress at the initial stage under three types of thermal conditions, with the addition of two kinds of mechanical boundary conditions.

scholarly journals Concrete strains under transient thermal conditions: A state-of-the-art review

2016 ◽  
Vol 127 ◽  
pp. 172-188 ◽  
Author(s):  
Giacomo Torelli ◽  
Parthasarathi Mandal ◽  
Martin Gillie ◽  
Van-Xuan Tran
Keyword(s):  
State Of The Art ◽  
Thermal Conditions ◽  
Transient Thermal

Trivariant Lagrange Factor Polynomial for Discrete Rayleigh Distributed Reliability Analysis of Aeroengine Combustion Chamber Cylinder

2013 ◽  
Vol 10 (1) ◽  
Author(s):  
Chun Nam Wong ◽  
Yang Lu
Keyword(s):  
Combustion Chamber ◽  
Thermal Conditions ◽  
Economic Factors ◽  
Structural Variants ◽  
Temperature Dependent ◽  
Application Range ◽  
Linear Polynomial ◽  
As Stress ◽  
Stress Dependent ◽  
Dependent Probability

In most of the existing stress-strength interference (SSI) models, stress and strength are assumed to be independent structural variants. However, under severe thermal conditions, such as in aeroengine combustion chamber, this assumption may not hold. One structural variant, such as strength, may become unilateral dependent on another variant, such as stress or temperature. In addition, to evaluate the discrete reliability of structures using unilateral dependent structural variants, discrete SSI models were developed using not just linear polynomial or line segments, but higher order polynomials. These models are based on the trivariant Lagrange factor polynomial approach. Normal distributed temperature dependent stress and Rayleigh distributed thermal stress dependent strength are represented by discrete structural variants that possess unilateral dependent probability mean functions. Based on their dependence formulations, the trivariant Lagrange factor polynomial of the discrete SSI model was generated. Applicability of this method was validated by a specific aeroengine combustion chamber cylinder using different molding alloys. Meanwhile the application range of some existing SSI models is extended for interval shifted data. Comparing machinability, reliability, and economic factors, 1Cr11MoV was the most suitable alloy in the design.

Modelling Semi-Solid Behaviour and Brittle Temperature Range

2019 ◽  
Vol 285 ◽  
pp. 361-366 ◽  
Author(s):  
Khalil Traidi ◽  
Véronique Favier ◽  
Philippe Lestriez ◽  
Karl Debray ◽  
Laurent Langlois ◽  
...  
Keyword(s):  
Solid State ◽  
Material Properties ◽  
Solid Phase ◽  
Thermal Conditions ◽  
Tensile Tests ◽  
Internal Variable ◽  
Temperature Dependent ◽  
Brittle Transition ◽  
Semi Solid ◽  
First Time

In this paper, a new elastic viscoplastic micromechanical modelling is proposed to represent the semi-solid behaviour and predict the ductile-brittle transition of the C38LTT near the solidus. It is based on a viscoplastic modelling previously presented in [1]. The originality of the new model comes from three main enhancements: the transition between the solid state and the semi-solid state was included meaning that the material properties were taken temperature-dependent, the elastic properties was taken into account similarly as [2] and the evolution of the internal variable describing the degree of agglomeration of the solid phase was enhanced. The model was implemented in the commercial software FORGE©. Tensile tests representing the experimental thermal conditions and obtained using a GLEEBLE© machine were simulated. The comparison of the predicted and experimental results shows that, for the first time to our knowledge, the three steps of the load-displacement response and ductile-brittle transition were successfully described.

The Effects of Severe Thermal and Pressure Transients on the Survival of Internally Coated Tubes

2010 ◽  
Author(s):  
J. T. Harris ◽  
A. E. Segall ◽  
R. Carter
Keyword(s):  
Finite Element ◽  
Thermal Stresses ◽  
Elastic Analysis ◽  
Uniform Heating ◽  
Temperature Dependent ◽  
Pressure Function ◽  
Stress States ◽  
Transient Thermal ◽  
Hoop Stresses ◽  
Over Time

The effects of severe thermal and pressure transient pulses on the interior of coated tubes have been analyzed using finite-element methods. For the modeling, an axisymmetric mesh was developed and used to assess the transient, thermal- and stress-states and the propensity for fracture related damage. For all calculations, temperature dependent thermophysical and elastic properties were used during the analysis. The model also utilized uniform heating and pressure across the ID surface imposed via convective coefficients and a piece-wise linear pressure function over time. Results for the strictly elastic analysis indicated that both had a significant influence on the maximum circumferential (hoop) stresses and temperatures and that the compressive thermal-stresses help to offset any tensile components generated by the internal pressure on the ID. Preliminary calculations also investigated the influence of these factors when a crack was introduced at the interface of the coating and substrate.

Temperature-Dependent Material Property Databases for Marine Steels—Part 1: DH36

2020 ◽  
Vol 9 (3) ◽  
pp. 257-286
Author(s):  
Daniel H. Bechetti ◽  
Jennifer K. Semple ◽  
Wei Zhang ◽  
Charles R. Fisher
Keyword(s):  
Material Property ◽  
Temperature Dependent

A Simplified Transient Thermal Analysis of Resistance Spot Welding Process

2010 ◽  
Vol 154-155 ◽  
pp. 443-446
Author(s):  
Zhi Gang Hou ◽  
Jun Zhao ◽  
Li Qiang Xu ◽  
Zhong Guo
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Complex Structure ◽  
Welding Process ◽  
Temperature Dependent ◽  
Resistance Spot ◽  
Whole Process ◽  
History Of ◽  
Transient Thermal

In order to theoretically simulate the welding process of complex structure with large quantities of welding spots, a simplified method for analyzing a single spot welding should be developed firstly. In this paper, a 2D axisymmetric model of thermoelectric Finite Element Method (FEM) is developed to analyze the transient thermal behavior of Resistance Spot Welding (RSW) process using ANSYS. The determination of the contact resistance at the faying surface is moderately simplified to reduce the calculating time, while the temperature dependent material properties, phase change and convectional boundary conditions are taken into account for the improvement of the calculated accuracy. The thermal history of the whole process and temperature distributions for any position in the weldment is obtained through the analysis. The model can also predict the weld nugget size and the width of the Heat Affected Zone (HAZ).

Sign in / Sign up

Export Citation Format

Share Document