Stress analysis of shielding electrode in chip with pressure sensor embedded in accelerometer

2019 ◽  
Vol 36 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Chun-Lin Lu ◽  
Meng-Kao Yeh
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Finite Element Model ◽  
Stress Analysis ◽  
Glass Substrate ◽  
Pressure Sensors ◽  
Element Model ◽  
Content Type ◽  
Out Of Plane ◽  
The Finite Element Model

Purpose Analysis of the thermal effects during the packaging process or in the actual operating environment is necessary to develop small monolithic integrated sensing chips with heterogeneous integration. The use of multiple layers and various materials in monolithic integrated sensing chips addresses the coefficient of thermal expansion (CTE) mismatch issue. The purpose of this study is to focus on the residual stress analysis of the shielding electrode, which is a metal film that prevents pull-in of proof-mass during anodic bonding in microelectromechanical system (MEMS) chips with pressure sensors embedded in an accelerometer. Design/methodology/approach The finite element model of the chip was built by the commercial software ANSYS, and the residual stress was evaluated during the die attachment process for the shielding electrode. Various shielding electrode materials and a proposed design with a keep-out zone to reduce the residual stress are discussed, with a focus on the relationship between the geometric parameters of the chip and the residual stress for copper shielding electrodes of different thicknesses. Findings The results of the finite element analysis showed that the use of polysilicon as a shielding electrode in the proposed design generated the lowest residual stress because of its low CTE. The maximum stresses in both of in-plane and out-of-plane directions in the finite element model were reduced by keep-out zone design for the proposed design of the copper shielding electrode, and had 11 times reduction in out-of-plane direction especially, according to the nonlinear analysis as the stress concentration point in the shielding electrode moved. Moreover, the design with a thinner shielding electrode, thinner glass substrate and higher CTE of the glass substrate also lowered the maximum von Mises stress. On the other hand, the stress level during the operating temperature, without considering residual stress, overestimated up to five times in the proposed design. Originality/value In this study, valuable suggestions are proposed for the design of chips with pressure sensors embedded in accelerometers.

Analysis on sealing performance of VL seals based on mixed lubrication theory

2019 ◽  
Vol 71 (1) ◽  
pp. 54-60 ◽  
Author(s):  
Shixian Xu ◽  
Zhengtao Su ◽  
Jian Wu
Keyword(s):  
Finite Element ◽  
Film Thickness ◽  
Finite Element Model ◽  
Friction Factor ◽  
Contact Pressure ◽  
Element Model ◽  
Mixed Lubrication ◽  
Content Type ◽  
Deformation Mechanics ◽  
The Finite Element Model

Purpose This paper aims to research the influence of pressure, friction factors, roughness and actuating speed to the mixed lubrication models of outstroke and instroke. Design/methodology/approach Mixed lubrication model is solved by finite volume method, which consists of coupled fluid mechanics, deformation mechanics and contact mechanics analyses. The influence of friction factor on the finite element model is also considered. Then, contact pressure, film thickness, friction and leakage have been studied. Findings It was found that the amount of leakage is sensitive to the film thickness. The larger the film thickness is, the greater the influence received from the friction factor, however, the effect of oil film on the friction is negligible. The friction is determined mainly by the contact pressure. The trend of friction and leakage influenced by actuating velocity and roughness is also obtained. Originality/value The influence of friction factor on the finite element model is considered. This can make the calculation more accurate.

Polarization Swiching in (111) Oriented PZT Thin Films

Aerospace ◽  
2006 ◽  
Author(s):  
William S. Oates ◽  
Alexei Gruverman
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Finite Element ◽  
Domain Wall ◽  
Finite Element Model ◽  
Applied Field ◽  
Polarization Switching ◽  
Element Model ◽  
Local Domain ◽  
The Finite Element Model

Local domain structures in Pb(Zr,Ti)O3 (PZT) ferroelectric thin films have been investigated using linear finite element analysis to qualitatively assess the effect of crystal structure, domain wall orientation and mechanical constraints from electrodes on local polarization switching behavior. The finite element model was used to illustrate that the evolution of residual stress during polarization reorientation may play an important role in the backswitching behavior which has been observed experimentally in (111)-orientated PZT films. The domain size and orientation used in the finite element model utilizes domain sizes determined from piezoresponse force microscopy (PFM) measurements given in the literature together with domain wall orientation from strain and charge compatibility in the (111) orientation. During polarization switching, domains with polarization components aligned anti-parallel to the applied field are expected to switch 90° to partially align with the applied field. 180° switching is not expected to occur in the (111) oriented film. The 90° switching induces residual stress that is computed using the finite element model. It is illustrated that thicker top electrodes increase the residual stress in the ferroelectric layer which may play an important role in polarization retention behavior in ferroelectric capacitors.

Residual Stress Finite Element Analysis and Measurements of a Tube Penetration J-Groove Attachment Weld in a Hemispherical Head of a Large Ferritic Pressure Vessel: Part II — Outer Nozzle

2006 ◽  
Author(s):  
R. Dennis ◽  
N. Leggatt ◽  
C. T. Watson ◽  
E. Kingston ◽  
D. J. Smith
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Pressure Vessel ◽  
Element Model ◽  
Hole Drilling ◽  
Poor Correlation ◽  
Element Analysis ◽  
The Finite Element Model

A programme of work was undertaken to gain an understanding of the residual stress levels in the tube penetration J-groove welds in a hemispherical head of a large stainless steel clad ferritic pressure vessel. This second part of a two-part paper describes the finite element analysis that was carried out to model an off-centre outer tube to vessel head weld. A 3D finite element residual stress model was developed. The complex bead deposition sequence of the actual weld was simulated by a bead lumping approach using 9 passes. The results from the finite element analyses were compared with both surface and through thickness stress measurements. These measurements were taken on a mock weld that was representative of the actual component. The surface measurements were taken by using an incremental centre hole drilling technique. The through thickness values were obtained from deep hole drilling measurements at three positions around the circumference of the weld. For this off-centre penetration the cladding process was not modelled nor was clad applied to the test mock-up. The finite element results and the measured values showed similar trends in the variation of stress around the circumference of the weld. A poor correlation between measurements and analytical results was obtained at the lower hillside position. A major reason for the discrepancy is believed to be that the bead lumping approach that was used in the finite element model was not a sufficiently refined representation of the actual weld bead deposition sequence. Note however that one of the aims of this finite element analysis was to quantify the variations between the centre tube presented in the first part of this paper and the off centre tube presented here. In this regard the finite element model and measurements compared well. The finite element model was also used to carry out two sensitivity studies that investigated the effects upon residual stress of tube geometry and material properties. For the case where a nozzle tube was extended significantly below the vessel head inner surface the results showed the stresses to be significantly higher than the baseline case.

Stress Analysis of the Pressurized-Water Reactor Control Rod Under Operating Conditions

2020 ◽  
Author(s):  
Leo A. Carrilho
Keyword(s):  
Finite Element ◽  
Thermal Expansion ◽  
Finite Element Model ◽  
Stress Analysis ◽  
Maximum Stress ◽  
Element Model ◽  
Operating Conditions ◽  
Pressurized Water ◽  
Control Rod ◽  
The Finite Element Model

Abstract This work aims to develop a finite element model of a PWR control rod at operating conditions for stress analysis of the rod cladding. The finite element model simulates a control rod exposed to high operating temperatures and pressure while portions of the rod are irradiated, resulting in accumulated fluence of neutrons by the rod materials. These high temperature and accumulated fluence induce thermal expansion and swelling of the rod materials, especially of the absorber, which may eventually interact with the rod cladding, generating stresses and strains in the wall of the cladding tube. Moreover, if the maximum stress or strain in the tube wall exceeds the design allowable limit, the absorber rod is considered failed. The author creates the control rod finite element model and apply the operating loads on two-dimensional axisymmetric elements to obtain displacements, temperatures, stresses, and strains. The model also includes contact surface elements to evaluate eventual mechanical interactions between absorber and cladding due to thermal expansion and swelling effects. This is a coupled nonlinear static analysis solution that includes thermal expansion effects to calculate temperature distribution and subsequent thermal strains in the absorber rod due to the heat generation rates and coolant temperature; swelling analysis to calculate absorber growth induced by irradiation; and creep analysis to calculate absorber stress relaxation under coolant pressure and temperature. The finite element model is capable of determining whether or not absorber-to-cladding gap closure will occur and if so, calculate maximum stress and strain in the rod cladding associated with mechanical interaction between the two components induced by the operating temperature and thermal fluence loads.

scholarly journals Sensitivity Analysis of the Influence of Structural Parameters on Dynamic Behaviour of Highly Redundant Cable-Stayed Bridges

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
B. Asgari ◽  
S. A. Osman ◽  
A. Adnan
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Structural Parameters ◽  
Element Model ◽  
Structural Behavior ◽  
Model Tuning ◽  
The Finite Element Model ◽  
Cable Stayed Bridges

The model tuning through sensitivity analysis is a prominent procedure to assess the structural behavior and dynamic characteristics of cable-stayed bridges. Most of the previous sensitivity-based model tuning methods are automatic iterative processes; however, the results of recent studies show that the most reasonable results are achievable by applying the manual methods to update the analytical model of cable-stayed bridges. This paper presents a model updating algorithm for highly redundant cable-stayed bridges that can be used as an iterative manual procedure. The updating parameters are selected through the sensitivity analysis which helps to better understand the structural behavior of the bridge. The finite element model of Tatara Bridge is considered for the numerical studies. The results of the simulations indicate the efficiency and applicability of the presented manual tuning method for updating the finite element model of cable-stayed bridges. The new aspects regarding effective material and structural parameters and model tuning procedure presented in this paper will be useful for analyzing and model updating of cable-stayed bridges.

Biodynamics of Human Thorax With Body Armors Subject to Bullet Impact

2001 ◽  
Author(s):  
Y. W. Kwon ◽  
J. A. Lobuono
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Body Armor ◽  
Projectile Impact ◽  
Human Thorax ◽  
Trachea And Bronchi ◽  
Armor System ◽  
The Finite Element Model

Abstract The objective of this study is to develop a finite element model of the human thorax with a protective body armor system so that the model can adequately determine the thorax’s biodynamical response from a projectile impact. The finite element model of the human thorax consists of the thoracic skeleton, heart, lungs, major arteries, major veins, trachea, and bronchi. The finite element model of the human thorax is validated by comparing the model’s results to experimental data obtained from cadavers wearing a protective body armor system undergoing a projectile impact.

Dynamic Analysis of a Turbocharger Centrifugal Compressor Impeller

1991 ◽  
Author(s):  
V. Ramamurti ◽  
D. A. Subramani ◽  
K. Sridhara
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Centrifugal Compressor ◽  
Element Model ◽  
Simplified Model ◽  
Cyclic Symmetry ◽  
Compressor Impeller ◽  
Cyclic Symmetric ◽  
The Finite Element Model

Abstract Stress analysis and determination of eigen pairs of a typical turbocharger compressor impeller have been carried out using the concept of cyclic symmetry. A simplified model treating the blade and the hub as isolated elements has also been attempted. The limitations of the simplified model have been brought out. The results of the finite element model using the cyclic symmetric approach have been discussed.

Analysis of Effective Pre-Stress of Continuous Rigid Frame Bridge in Service Based on Inversion Theory

2013 ◽  
Vol 671-674 ◽  
pp. 1012-1015
Author(s):  
Zhao Ning Zhang ◽  
Ke Xing Li
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Inversion Method ◽  
Vertical Deflection ◽  
Continuous Rigid Frame Bridge ◽  
Rigid Frame ◽  
Inversion Theory ◽  
Rigid Frame Bridge ◽  
The Finite Element Model

Due to the environment, climate, loads and other factors, the pre-stress applied to the beam is not a constant. It is important for engineers to track the state of the pre-stress in order to ensure security of the bridge in service. To solve the problem mentioned above, the paper puts forward a new way to analyze the effective pre-stress using the displacement inversion method based on the inversion theory according to the measured vertical deflection of the bridge in service at different time. The method is a feasible way to predict the effective pre-stress of the bridge in service. Lastly, taking the pre-stressed concrete continuous rigid frame bridge for example, the effective pre-stress is analyzed by establishing the finite element model.

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