Roof deformation and collapse of stamps with isolated grooves: a contact mechanics approach

2021 ◽  
pp. 1-22
Author(s):  
Fan Jin ◽  
Changyu Tang ◽  
Xu Guo ◽  
Longteng Bai
Keyword(s):  
Contact Mechanics ◽  
Applied Load ◽  
Full Range ◽  
Applied Pressure ◽  
Elastic Strain Energy ◽  
Interfacial Stress ◽  
Element Analysis ◽  
Strong Adhesion ◽  
Contact Size ◽  
Roof Deformation

Abstract This paper has revisited the roof deformation and collapse of stamps with isolated grooves based on a contact mechanics approach, with emphasis on establishing the non-adhesive and adhesive contact solutions for surfaces containing a shallow rectangular groove with the effects of applied load and interfacial adhesion taken into account. By solving singular integral equations and using the energy release rate approach, closed-form solutions are derived analytically for the deformed groove shapes, interfacial stress distributions and equilibrium relations between load and contact size, which reduce to the previously proposed solutions without adhesion or without applied load. Finite element analysis is performed to validate the non-adhesion solutions, while experiment results of stamp collapse reported in the literature are adopted to examine the adhesion solutions. By introducing the Johnson parameter a to represent a competition between surface energy and elastic strain energy of the groove, four kinds of contact behaviors of the groove roof can be characterized appropriately: non-adhesion, weak adhesion, intermediate adhesion and strong adhesion. Hysteresis loop and energy loss due to distinct load/unloading paths are revealed in the cases of intermediate and strong adhesion. We also provided the critical applied pressure to achieve roof collapse and the corresponding equilibrium contact size for full range of a.

Selecting the Optimum Bolt Assembly Stress: Influence of Flange Type on Flange Load Limit

2008 ◽  
Author(s):  
Warren Brown
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Carbon Steel ◽  
Applied Load ◽  
Hoop Stress ◽  
Elastic Analysis ◽  
Steel Weld ◽  
Element Analysis ◽  
Load Limit ◽  
Stress Influence

In previous papers, practical limits on the maximum applied load for standard ASME B16.5 and B16.47 carbon steel, weld neck pipe flanges were examined. A new code equation for the tangential (hoop) stress at the small end of the hub for a weld neck flange was developed to facilitate calculation of the limits using elastic analysis. The results were verified against elastic-plastic Finite Element Analysis (FEA). In this paper, the work is extended to include other flange configurations, including loose ring flanges, slip-on flanges and flat plate flanges. This paper is a continuation of the papers presented during PVP 2006 and PVP 2007 (Brown [1, 2]) and it extends the scope of the proposed methodology for determining flange stress limits in determining the maximum allowable bolt load for any given flange size and configuration.

Numerical Optimization of Silicon Stacked Module for 3-D Packaging Applications

2008 ◽  
Vol 5 (2) ◽  
pp. 68-76
Author(s):  
Akella G.K. Viswanath ◽  
Xiaowu Zhang ◽  
Y.Y. Wang ◽  
S.W. Yoon ◽  
Navas Khan ◽  
...  
Keyword(s):  
Solder Joint ◽  
Functional Integration ◽  
Three Dimensional ◽  
Interfacial Stress ◽  
Electrical Performance ◽  
Thickness Variation ◽  
Element Analysis ◽  
Variation Of Parameters ◽  
Optimization Study ◽  
Electroplated Copper

Three-dimensional package format has gained more popularity for various applications because of the trend toward higher functional integration, miniaturization, and better electrical performance. This paper presents a design optimization study of a 3-D package using a silicon interposer. The package consists of three stacks with five dies. Electrical connections through the silicon interposers are done by through-silicone vias (TSVs) filled with electroplated copper. Initially, structural optimization of the package is conducted by a 2-D finite element analysis and later, statistical analysis is performed to estimate the coupled effects of parameters considered for the design. Carrier thickness variation is found to be the most significant effect on the package warpage. Interfacial stress between the copper plug and the silicon via hole has been investigated and reported. A 3-D model is constructed for the solder joint reliability study with SnAgCu material properties. Solder joint life with variation of parameters (i.e., board level underfill, higher standoff solder interconnect, and low CTE board) is studied, and all results are reported accordingly.

Melan’s Problems With Weak Interface

1999 ◽  
Vol 67 (1) ◽  
pp. 22-28 ◽  
Author(s):  
S. Lenci
Keyword(s):  
Closed Form ◽  
Applied Load ◽  
Interface Stress ◽  
Interfacial Stress ◽  
Weak Interface ◽  
Concentrated Force ◽  
Zone Of Influence ◽  
Two Bodies

The problem of a fiber attached to an infinite sheet (Melan’s problem) has been reconsidered under the hypothesis that the adherence between the two bodies is not perfect. We have assumed that the link is guaranteed by the so-called “weak interface,” i.e., we have supposed that the jump of the displacement is linearly proportional to the interface stress. The solutions of (i) the case with a concentrated force acting on the fiber and (ii) the case of the redistribution of stresses as a consequence of the rupture of the fiber have been obtained in closed form. We have discussed how the interface stiffness k influences the solutions and, in particular, the interfacial stress. Emphasis is placed on determining how the zone of influence of the applied load is modified by k. Approximate (though accurate) simple expressions for the length of the zone of influence are given and discussed. [S0021-8936(00)01001-1]

Modeling Stresses in Polyimide Films

1993 ◽  
Vol 308 ◽  
Author(s):  
Michael T. Pottiger ◽  
John C. Coburn
Keyword(s):  
Finite Element Analysis ◽  
Computer Modeling ◽  
Entire Range ◽  
Applied Load ◽  
Narrow Range ◽  
A Priori ◽  
Material Behavior ◽  
Polyimide Films ◽  
Element Analysis ◽  
The Ideal

The trend towards higher density and smaller feature sizes in today's devices, and the increasing costs associated with designing and manufacturing these devices, has placed a greater emphasis on obtaining an a priori understanding of how various materials will perform in a device. A number of manufacturers have turned to computer modeling, utilizing finite element analysis to aid in the design of new devices and reduce the costs associated with preparing prototypes. The use of computer modeling requires a constitutive equation relating the response of a material to an applied load. Polymer behavior is complex and writing an equation or a series of equations that describe the behavior of the polymer over the entire range of possible temperatures and deformations is nontrivial. Instead, series of equations that describe ideal material behavior are used in an attempt to describe the behavior of real materials over a narrow range of temperatures and deformations. For solids, the ideal material response that is generally used to describe real polymer behavior is linear elasticity.

Mechanical Behaviour of Auxetic Microstructures Using Contact Mechanics and Elastoplasticity

2016 ◽  
Vol 681 ◽  
pp. 100-116
Author(s):  
Georgios A. Drosopoulos ◽  
Nikolaos Kaminakis ◽  
Nikoletta Papadogianni ◽  
Georgios E. Stavroulakis
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Topology Optimization ◽  
Contact Mechanics ◽  
Compliant Mechanisms ◽  
Nonlinear Finite Element Analysis ◽  
Nonlinear Finite Element ◽  
Numerical Homogenization ◽  
Element Analysis ◽  
Optimization Formulation

The design of novel mechanical microstructures having auxetic behaviour is proposed in this paper using techniques of topology optimization for compliant mechanisms. The resulting microstructure can be modified in order to cover additional needs, not included in the topology optimization formulation. Classical structural optimization, contact mechanics, homogenization and nonlinear finite element analysis are used for this step. Thus, the modified microstructure or composite is studied with numerical homogenization in order to verify that it still has the wished auxetic behaviour. Finally, nonlinear finite element analysis shows how the auxetic behaviour is influenced by unilateral contact between the constituent materials, large displacements and elastoplasticity.

Thermal Imprint Process of Parylene for MEMS Applications

2007 ◽  
Vol 340-341 ◽  
pp. 931-936 ◽  
Author(s):  
Sung Won Youn ◽  
Hiroshi Goto ◽  
Masaharu Takahashi ◽  
M. Ogiwara ◽  
Ryutaro Maeda
Keyword(s):  
Applied Load ◽  
Hold Time ◽  
Applied Pressure ◽  
Silicon Etching ◽  
Release Agent ◽  
Temperature Range ◽  
Complete Filling ◽  
Electroplating Process ◽  
Increasing Temperature

This study investigated a thermal imprint technique to pattern parylene microstructures over an area of 2525 mm2. A nickel mold having arrays of 25 m-high, 10 m-wide and 1 mm-long lines with 10 m spacing was fabricated using the deep RIE silicon etching followed by the electroplating process. Imprint tests were then carried out under different conditions of temperature, imprint-hold time and applied pressure to investigate a thermal imprint condition for the complete filling of parylene. Good release results without damage or deformation in parylene microstructures were achieved by the help of a release agent in the imprint temperature range of 160 oC to 250oC. With increasing temperature, the depths of imprinted structures increased and their distribution came to be homogeneous. Complete filling was obtained under the imprint temperature of 250oC, applied load of 195 kgf (3 MPa) and imprint hold time of 1800 s.

Simulation of Low Pressure MEMS Sensor for Biomedical Application

2011 ◽  
Vol 2 (3) ◽  
Author(s):  
S. Sathyanarayanan ◽  
A. Vimala Juliet
Keyword(s):  
Pressure Sensor ◽  
Microelectromechanical Systems ◽  
Biomedical Application ◽  
Applied Pressure ◽  
Analysis Data ◽  
Operating Pressure ◽  
Capacitive Pressure Sensor ◽  
Element Analysis ◽  
Mems Sensor ◽  
Relationship Of

Micromachining technology has greatly benefited from the success of developments in implantable biomedical microdevices. In this paper, microelectromechanical systems (MEMS) capacitive pressure sensor operating for biomedical applications in the range of 20–400 mm Hg was designed. Employing the microelectromechanical systems technology, high sensor sensitivities and resolutions have been achieved. Capacitive sensing uses the diaphragm deformation-induced capacitance change. The sensor composed of a rectangular polysilicon diaphragm that deflects due to pressure applied over it. Applied pressure deflects the 2 µm diaphragm changing the capacitance between the polysilicon diaphragm and gold flat electrode deposited on a glass Pyrex substrate. The MEMS capacitive pressure sensor achieves good linearity and large operating pressure range. The static and thermo electromechanical analysis were performed. The finite element analysis data results were generated. The capacitive response of the sensor performed as expected according to the relationship of the spacing of the plates.

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