Mechanical Analysis for Thermal Grease Enhanced Modules Enclosing a Silicon Chip

1989 ◽  
Vol 111 (2) ◽  
pp. 90-96 ◽  
Author(s):  
P. A. Engel ◽  
D. H. Strope ◽  
T. E. Wray
Keyword(s):  
Heat Conduction ◽  
Thermal Loading ◽  
Structural Integrity ◽  
Mechanical Analysis ◽  
Mechanical Stresses ◽  
Ceramic Technology ◽  
Cyclic Thermal Loading ◽  
Thermal Grease

In metallized ceramic technology substantial mechanical stresses arise in assembly, insertion and cyclic thermal loading of thermally enhanced modules. This paper describes some experimental and analytical investigations performed for safeguarding the structural integrity of modules in which heat conduction from the chip to the module cap was enhanced by a “thermal grease” compound.

Approximate method for the analysis of components undergoing ratchetting and failure

1998 ◽  
Vol 33 (1) ◽  
pp. 55-65 ◽  
Author(s):  
J Lin ◽  
F P E Dunne ◽  
D R Hayhurst
Keyword(s):  
Approximate Method ◽  
Mechanical Loading ◽  
Thermal Loading ◽  
Cyclic Plasticity ◽  
Processing Unit ◽  
Computationally Efficient ◽  
Element Analysis ◽  
Cyclic Thermal Loading ◽  
Central Processing ◽  
Practical Design

An approximate method has been presented for the design analysis of engineering components subjected to combined cyclic thermal and mechanical loading. The method is based on the discretization of components using multibar modelling which enables the effects of stress redistribution to be included as creep and cyclic plasticity damage evolves. Cycle jumping methods have also been presented which extend previous methods to handle problems in which incremental plastic straining (ratchetting) occurs. Cycle jumping leads to considerable reductions in computer CPU (central processing unit) resources, and this has been shown for a range of loading conditions. The cycle jumping technique has been utilized to analyse the ratchetting behaviour of a multibar structure selected to model geometrical and thermomechanical effects typically encountered in practical design situations. The method has been used to predict the behaviour of a component when subjected to cyclic thermal loading, and the results compared with those obtained from detailed finite element analysis. The method is also used to analyse the same component when subjected to constant mechanical loading, in addition to cyclic thermal loading leading to ratchetting. The important features of the two analyses are then compared. In this way, the multibar modelling is shown to enable the computationally efficient analysis of engineering components.

Mechanical Reliability of Photovoltaic Cells under Cyclic Thermal Loading

2019 ◽  
Vol 49 (1) ◽  
pp. 59-71
Author(s):  
Dipali Sonawane ◽  
Praveen C. Ramamurthy ◽  
Praveen Kumar
Keyword(s):  
Thermal Loading ◽  
Photovoltaic Cells ◽  
Mechanical Reliability ◽  
Cyclic Thermal Loading

On the Design of Contact Member Surface Shape of Bolted Joints to Minimize Clamping Load Loss

2018 ◽  
Author(s):  
Linbo Zhu ◽  
Yifei Hou ◽  
Abdel-Hakim Bouzid ◽  
Jun Hong
Keyword(s):  
Contact Surface ◽  
High Performance ◽  
Thermal Loading ◽  
Structural Integrity ◽  
Bolted Joints ◽  
Surface Shape ◽  
Geometrical Shape ◽  
Joint Surfaces ◽  
Joint Contact ◽  
The Stability

Metal to metal contact between joint surfaces is widely used in bolted joints to obtain a rigid and a high performance connection. However, a significant amount of clamping load is lost when the joint is subjected to mechanical and thermal loading including creep and fatigue. In practice, to prevent bolt loosening, additional parts such as spring washers, double nut, spring lock washers, Nyloc nut and so on are used. Those methods are costly and influence the stability of the joint and affect its structural integrity. It is well established that a small compression displacement in clamping parts leads to a big clamping load loss in stiff joints. This paper discusses the relationship between connection stiffness and clamping load and presents a method that improves clamping load retention during operation by a careful design of the member contact surface shape. A single bolted joint with two clamping parts is modeled using finite element method (FEM). A method is proposed to obtain a specific stiffness by an optimized geometrical shape of the joint contact surfaces. The result shows that the contact surface shape based on a gradually varying gap can improve the retention of the initial clamping load. Furthermore, a formula of the connection stiffness based on the curve fitting technique is proposed to predict residual clamping load under different external load and loosening.

scholarly journals Thermal deformation of gold nanostructures and its influence on surface plasmon resonance sensing

2020 ◽  
Vol 2 (3) ◽  
pp. 1128-1137
Author(s):  
Hyun-Tae Kim ◽  
Mayank Pathak ◽  
Keshav Rajasekaran ◽  
Ashwani K. Gupta ◽  
Miao Yu
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Thermal Deformation ◽  
Thermal Loading ◽  
Gold Nanostructures ◽  
Cyclic Thermal Loading

The deformation of lithographic planar gold nanostructures under cyclic thermal loading and its influence on surface plasmon resonance sensing are investigated.

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