A 3D Numerical Study to Investigate the Effects of Temperature Variation and Residual Stresses in Representative Volume MEMS Elements

2010 ◽  
Author(s):  
A. R. Maligno ◽  
D. C. Whalley ◽  
V. V. Silberschmidt
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Residual Stresses ◽  
Numerical Study ◽  
Manufacturing Processes ◽  
The Finite Element Method ◽  
Physics Of Failure ◽  
Temperature Variations ◽  
Failure Initiation ◽  
Effects Of Temperature

The reliability of MEMS, and in particular of RF MEMES switches, might be increased by the use of a Physics of Failure (PoF) methodology. A numerical study, based on the finite element method (FEM), has been carried out to investigate the effects of temperature variations on failure (e.g. yielding of metals) onset within multilayered MEMS structures. Furthermore, the manufacturing processes of MEMS are the main sources of residual stresses development and they represent one of the most profound factors reducing the functionality and reliability of MEMS packages. Therefore, the effect of residual stresses on failure onset has been considered in these studies to examine their effects on MEMS reliability. Numerical results have shown that failure initiation is strongly influenced by the loading conditions (i.e. different range of temperatures), boundary conditions and finally by the presence of residual stresses.

Application of FEM Modeling to Simulate Metal Flow in Forging a Titanium Alloy Engine Disk

1983 ◽  
Vol 105 (4) ◽  
pp. 251-258 ◽  
Author(s):  
S. I. Oh ◽  
J. J. Park ◽  
S. Kobayashi ◽  
T. Altan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Titanium Alloy ◽  
Metal Flow ◽  
The Finite Element Method ◽  
Fem Modeling ◽  
Forging Process ◽  
Deformation Mechanics ◽  
Effects Of Temperature ◽  
Element Method

The isothermal forging of a titanium alloy engine disk is analyzed by the rigid-viscoplastic finite element method. Deformation mechanics of the forging process are discussed, based on the solution. The effects of temperature and heat conduction on the forging process are also investigated by coupled thermo-viscoplastic analysis. Since the dual microstructure / property titanium disk can be obtained by controlling strain distribution during forging, the process modeling by the finite element method is especially attractive.

Analysis of Aerodynamic Journal Bearings With Small Number of Herringbone Grooves by Finite Element Method

1994 ◽  
Vol 116 (4) ◽  
pp. 698-704 ◽  
Author(s):  
D. Bonneau ◽  
J. Absi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Study ◽  
Load Capacity ◽  
Journal Bearings ◽  
The Finite Element Method ◽  
Bearing Number ◽  
Comparison Of The Results ◽  
Herringbone Grooves ◽  
Element Method

A numerical study of gas herringbone grooved journal bearings is presented for small number of grooves. The compressible Reynolds equation is solved by use of the Finite Element Method. The nonlinearity of the discretized equations is treated with the Newton-Raphson procedure. A comparison of the results for a smooth bearing with previously published results is made and the domain of validity of the Narrow Groove Theory is analyzed. Load capacity, attitude angle, and stiffness coefficients are given for various configurations: groove angle and thickness of grooves, bearing number, and that for both smooth and grooved member rotating.

Three-phase micromechanical analysis of residual stresses in reinforced fiber by carbon nanotubes

2016 ◽  
Vol 51 (12) ◽  
pp. 1783-1794 ◽  
Author(s):  
Ahmad Reza Ghasemi ◽  
Mohammad Mohammadi Fesharaki ◽  
Masood Mohandes
Keyword(s):  
Finite Element Method ◽  
Carbon Nanotubes ◽  
Finite Element ◽  
Carbon Fiber ◽  
Residual Stresses ◽  
Representative Volume Element ◽  
Volume Element ◽  
The Finite Element Method ◽  
Representative Volume ◽  
Element Method

In this study, circular disk model and cylinder theory for two dimension (2D) and three dimension (3D), respectively, have been used to determine residual stresses in three-phase representative volume element. The representative volume element is consisting of three phases: carbon fiber, carbon nanotubes, and polymer matrix, that carbon fiber is reinforced by carbon nanotube using electrophoresis method. Initially, the residual stresses analysis of two-phase representative volume element has been implemented. The two-phase representative volume element has been divided to carbon fiber and matrix phases with different volume fractions. In the three-phase representative volume element, although the volume fraction of carbon fiber is constant and equal to 60%, the volume fractions of carbon nanotubes for various cases are different as 0%, 1%, 2%, 3%, 4%, and 5%. Also, there are two different methods to reinforce the fiber according to different coefficients of thermal expansion of the carbon fiber and carbon nanotube in two longitudinal and transverse directions; carbon nanotubes are placed on carbon fiber either parallel or around it like a ring. Subsequently, finite element method and circular disk model have been used for analyzing micromechanic of the residual stresses for 2D and then the results of stress invariant obtained by the finite element method have been compared with the circular disk model. Moreover, for 3D model, the finite element method and cylinder theory have been utilized for micromechanical analysis of the residual stresses and the results of stress invariant obtained by them, have been compared with each other. Results of the finite element method and analytical model have good agreement in 2D and 3D models.

scholarly journals NUMERICAL STUDY ON EFFECTS OF TENON SIZES ON WITHDRAWAL LOAD CAPACITY OF MORTISE AND TENON JOINT

Wood Research ◽  
2021 ◽  
Vol 66 (2) ◽  
pp. 321-330
Author(s):  
Tianxing Zhang ◽  
Wengang Hu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Response Surface ◽  
Numerical Study ◽  
Load Capacity ◽  
The Finite Element Method ◽  
Surface Method ◽  
Mortise And Tenon ◽  
Relationship Of ◽  
The Relationship

The effect of tenon length and tenon width on withdrawal load capacity of mortise and tenon (M-T) joint was studied based on the finite element method (FEM), and the relationship of withdrawal load capacity relating to tenon length and tenon width was regressed using response surface method. The results showed that the tenon length and tenon width had remarkable effects on withdrawal load capacity of M-T joint T-shaped sample. The effect of tenon length on withdrawal load capacity was greater than tenon width. The regression equation used to predict the withdrawal load capacity was capable of optimizing the tenon sizes of M-T joint with R-square of 0.926. Using FEM can get more knowledge of M-T joint visually, and reduce the costs of materials and time of experiments.

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