Mechanical Properties and Stresses in Thin Gold Films on a Silicon Substrate

2001 ◽  
Vol 695 ◽  
Author(s):  
Changjin Xie ◽  
Richard D. Emery ◽  
Seung-Yong Yang ◽  
Wei Tong

ABSTRACTThin gold films with a thickness of 2mm were deposited on a silicon substrate by electron-beam evaporation. The material microstructure and internal stresses of the as-deposited gold films were characterized by scanning ion microscopy, orientation imaging microscopy, and X-ray diffraction. Microtensile tests of free-standing gold film samples were carried out to establish their intrinsic mechanical properties (in connection with a finite element analysis using crystal plasticity). Nanoindentation tests of the thin gold films attached to the silicon substrate were also carried out. Finite element analyses incorporating the crystal plasticity model were used to evaluate the effects of thin film textures, constraints due to the elastic substrate, and internal stresses on the plastic deformation behavior of the thin gold films under indentation at a direction normal to the film surfaces. Results of the combined experimental and numerical investigation indicate that the internal stresses have a strong effect on the uniaxial compression stress-strain behavior of the gold films and it may contribute to the relatively large hardness numbers obtained from the nanoindentation tests.

2011 ◽  
Vol 243-249 ◽  
pp. 1461-1465
Author(s):  
Chuan Min Zhang ◽  
Chao He Chen ◽  
Ye Fan Chen

The paper makes an analysis of the reinforced concrete beams with exterior FRP Shell in Finite Element, and compares it with the test results. The results show that, by means of this model, mechanical properties of reinforced concrete beams with exterior FRP shell can be predicted better. However, the larger the load, the larger deviation between calculated values and test values. Hence, if more accurate calculation is required, issues of contact interface between the reinforced concrete beams and the FRP shell should be taken into consideration.


2021 ◽  
pp. 073168442199086
Author(s):  
Yunfei Qu ◽  
Dian Wang ◽  
Hongye Zhang

The double V-wing honeycomb can be applied in many fields because of its lower mass and higher performance. In this study, the volume, in-plane elastic modulus and unit cell area of the double V-wing honeycomb were analytically derived, which became parts of the theoretical basis of the novel equivalent method. Based on mass, plateau load, in-plane elastic modulus, compression strain and energy absorption of the double V-wing honeycomb, a novel equivalent method mapping relationship between the thickness–width ratio and the basic parameters was established. The various size factor of the equivalent honeycomb model was denoted as n and constructed by the explicit finite element analysis method. The mechanical properties and energy absorption performance for equivalent honeycombs were investigated and compared with hexagonal honeycombs under dynamic impact. Numerical results showed a well coincidence for each honeycomb under dynamic impact before 0.009 s. Honeycombs with the same thickness–width ratio had similar mechanical properties and energy absorption characteristics. The equivalent method was verified by theoretical analysis, finite element analysis and experimental testing. Equivalent honeycombs exceeded the initial honeycomb in performance efficiency. Improvement of performance and weight loss reached 173.9% and 13.3% to the initial honeycomb. The double V-wing honeycomb possessed stronger impact resistance and better load-bearing capacity than the hexagonal honeycomb under impact in this study. The equivalent method could be applied to select the optimum honeycomb based on requirements and improve the efficiency of the double V-wing honeycomb.


Author(s):  
A. Ajdari ◽  
P. K. Canavan ◽  
H. Nayeb-Hashemi ◽  
G. Warner

Three-dimensional structure of trabecular bone can be modeled by 2D or 3D Voronoi structure. The effect of missing cell walls on the mechanical properties of 2D honeycombs is a first step towards understanding the effect of local bone resorption due to osteoporosis. In patients with osteoporosis, bone mass is lost first by thinning and then by resorption of the trabeculae [1]. Furthermore, creep response is important to analyze in cellular solids when the temperature is high relative to the melting temperature. For trabecular bone, as body temperature (38 °C) is close to the denaturation temperature of collagen (52 °C), trabecular bone creeps [1]. Over the half of the osteoporotic vertebral fractures that occur in the elderly, are the result of the creep and fatigue loading associated with the activities of daily living [2]. The objective of this work is to understand the effect of missing walls and filled cells on elastic-plastic behavior of both regular hexagonal and non-periodic Voronoi structures using finite element analysis. The results show that the missing walls have a significant effect on overall elastic properties of the cellular structure. For both regular hexagonal and Voronoi materials, the yield strength of the structure decreased by more than 60% by introducing 10% missing walls. In contrast, the results indicate that filled cells have much less effect on the mechanical properties of both regular hexagonal and Voronoi materials.


2015 ◽  
Vol 83 ◽  
pp. 75-84 ◽  
Author(s):  
S. Haroush ◽  
E. Priel ◽  
D. Moreno ◽  
A. Busiba ◽  
I. Silverman ◽  
...  

2007 ◽  
Vol 546-549 ◽  
pp. 1673-1676 ◽  
Author(s):  
Wei Jia Meng ◽  
Zhan Wen Huang ◽  
Yan Ju Liu ◽  
Xiao Rong Wu ◽  
Yi Sun

Magnetorheological (MR) fluids are suspensions of micron sized ferromagnetic particles dispersed in varying proportions of a variety of non-ferromagnetic fluids. MR fluids exhibit rapid, reversible and significant changes in their rheological (mechanical) properties while subjected to an external magnetic field. In this paper, a double-plate magneto-rheological fluid (MRF) clutch with controllable torque output have been designed. Electromagnetic finite element analysis is used to optimize the design of the clutch by using the commercial FEA software ANSYS.


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