A Stress Singularity Parameter Approach for Evaluating the Interfacial Reliability of Plastic Encapsulated LSI Devices

1989 ◽  
Vol 111 (4) ◽  
pp. 243-248 ◽  
Author(s):  
T. Hattori ◽  
S. Sakata ◽  
G. Murakami
Keyword(s):  
Adhesive Strength ◽  
Evaluation Method ◽  
Stress Singularity ◽  
The Finite Element Method ◽  
Displacement Fields ◽  
Stress And Displacement Fields ◽  
Ni Alloy ◽  
Base Resin ◽  
Interfacial Reliability ◽  
Parameter Approach

Since the stress and displacement fields near a bonding edge show singularity behaviors, the adhesive strength evaluation method, using maximum stresses calculated by a numerical stress analysis such as the finite element method, is generally not valid. In this paper, a new method, which uses two stress singularity parameters, is presented for evaluating adhesive strength. This method is applied to several kinds of molded models, composed of epoxy base resin and Fe-Ni alloy sheets, and plastic encapsulated LSI models. Predictions about the initiation and extension of delamination are compared with the results of observations made by scanning acoustic tomography on these models.

Fatigue Strength Evaluation Methods Using Stress Distributions

2009 ◽  
Vol 417-418 ◽  
pp. 409-412
Author(s):  
F. Nakamura ◽  
Tomoyasu Abe ◽  
Toshio Hattori ◽  
Minoru Yamashita
Keyword(s):  
Fatigue Crack Initiation ◽  
Stress Singularity ◽  
Critical Distance ◽  
Stress Intensity Factor Range ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Displacement Fields ◽  
Strength Criteria ◽  
Stress And Displacement Fields ◽  
Threshold Stress Intensity Factor

The stress and displacement fields near the bonding edge, sharp notch, and contact edge show singularity behaviours, so methods of evaluating the strength of these points using maximum stresses calculated by a numerical stress analysis, such as the finite element method, are generally not valid. We have previously presented a new method of evaluating the strength of these singular points using two stress singularity parameters H and λ. In this paper we have developed a method of formularizing critical stress-singularity parameter Hth for each order of stress singularity λ by utilizing critical distance stress theories (point method and line method), which can be derived from two typical strength parameters, namely, fatigue limit σw0 and threshold stress-intensity factor range ΔKth. These estimated critical Hth (λ) value agreed well with the experimentally measured value. Using these simple critical distance stress approach we estimated the fretting-fatigue-crack initiation criteria for any contact edge angle and optimized the contact-edge geometry. Moreover, we apply this new strength criteria to general stress concentration structures.

Penetration of a Half Space by a Rectangular Cylinder

1979 ◽  
Vol 46 (3) ◽  
pp. 587-591 ◽  
Author(s):  
A. Cemal Eringen ◽  
F. Balta
Keyword(s):  
Half Space ◽  
Stress Singularity ◽  
Elastic Solid ◽  
Interatomic Interaction ◽  
Elastic Half Space ◽  
Rigid Block ◽  
Field Equations ◽  
Displacement Fields ◽  
Rectangular Cylinder ◽  
Stress And Displacement Fields

The stress and displacement fields are determined in an elastic half space loaded by a rectangular frictionless, rigid block normally at its surface. The semi-infinite solid is considered to be an elastic solid with nonlocal interatomic interaction. The field equations of the nonlocal elasticity and boundary conditions are employed to treat this contact problem. Interestingly the classical stress singularity at the edges of the block are not present in the nonlocal solutions. Consequently the critical applied load for the initiation of penetration of the rigid cylinder into the semi-infinite solid can be determined without recourse to any criterion foreign to the theory. The stress field obtained is valid even for penetrators of submicroscopic width.

Uniaxial Loading in an Elastic Continuum With a Doubly Periodic Array of Material Discontinuities

1969 ◽  
Vol 36 (1) ◽  
pp. 134-139 ◽  
Author(s):  
G. H. Gaonkar
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Periodic Array ◽  
Numerical Comparison ◽  
The Finite Element Method ◽  
Displacement Fields ◽  
Elastic Continuum ◽  
Stress And Displacement Fields ◽  
Material Discontinuities ◽  
Doubly Periodic Array

Stress and displacement fields are presented for uniaxially loaded infinite elastic continua with a doubly periodic array of holes, elastic or rigid inclusions with or without overlapping. The results are obtained by using an appropriate form of the finite-element method. When possible, a numerical comparison has been made with known solutions. In the treatment of not previously studied configurations, the convergence is ascertained by observing the trend with finer discretizations.

Gravitational stress field around a tunnel in soft ground

1970 ◽  
Vol 7 (1) ◽  
pp. 54-61 ◽  
Author(s):  
B. Hoyaux ◽  
B. Ladanyi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Infinite Medium ◽  
Soft Ground ◽  
The Finite Element Method ◽  
Short Term ◽  
Displacement Fields ◽  
Stress And Displacement Fields ◽  
Gravitational Stress ◽  
Material Behaviors

The finite element method has been used for determining the stress distribution and the displacements due to gravity around an unlined tunnel driven through a semi-infinite medium, characterized by three idealized material behaviors reflecting approximately a short term behavior of natural undisturbed insensitive and sensitive clays. The knowledge of stress and displacement fields around an unlined tunnel can be used for evaluating the need for supports according to the acceptability of expected deformations.

Stress Behavior at the Interface Junction of an Elastic Inclusion

2002 ◽  
Vol 69 (6) ◽  
pp. 844-852 ◽  
Author(s):  
Z. Q. Qian ◽  
A. R. Akisanya ◽  
D. S. Thompson
Keyword(s):  
Finite Element ◽  
Elastic Inclusion ◽  
Symmetric Mode ◽  
The Finite Element Method ◽  
Displacement Fields ◽  
Two Phase ◽  
Stress And Displacement Fields ◽  
Higher Order Terms ◽  
The Matrix ◽  
Finite Element Prediction

The stress distribution at the interface junction of an elastic inclusion embedded in a brittle matrix is examined. Solutions are derived for the stress and displacement fields near the junction formed by the intersection of the interfaces between the inclusion and the matrix. The stress field consists of symmetric (mode I) and skew-symmetric (mode II) components. The magnitude of the intensity factor associated with each mode of deformation is determined using a combination of the finite element method and a contour integral. The numerical results of the stresses near the interface junction of two different inclusion geometries show that the asymptotic solutions of the stresses are in agreement with those from the finite element prediction when higher-order terms are considered. The implications of the results for the failure of particle-reinforced and two-phase brittle materials are discussed.

scholarly journals A Stress Singularity Parameter Approach for Evaluating Adhesive Strength

1988 ◽  
Vol 31 (4) ◽  
pp. 718-723 ◽  
Author(s):  
Toshio HATTORI ◽  
Sohji SAKATA ◽  
Toshio HATSUDA ◽  
Gen MURAKAMI
Keyword(s):  
Adhesive Strength ◽  
Stress Singularity ◽  
Parameter Approach

Fatigue Strength Evaluation Methods Using Stress Distributions

2010 ◽  
Author(s):  
T. Hattori ◽  
M. Yamashita
Keyword(s):  
Fatigue Strength ◽  
Stress Singularity ◽  
Elliptical Hole ◽  
Critical Distance ◽  
Experimental Results ◽  
Stress Intensity Factor Range ◽  
Round Hole ◽  
Displacement Fields ◽  
Stress And Displacement Fields ◽  
Threshold Stress Intensity Factor

The stress and displacement fields near the bonding edge, sharp notch, and contact edge show singularity behaviors, so methods of evaluating the strength of these points using maximum stresses calculated by a numerical stress analysis, such as the finite element method, are generally not valid. We have previously presented a new method of evaluating the strength of these singular points using two stress singularity parameters H and λ and developed a method of formulating critical stress-singularity parameter Hth for each order of stress singularity λ by utilizing critical distance stress theories (point method and line method), which can be derived from two typical strength parameters, namely, fatigue limit σw0 and threshold stress-intensity factor range ΔKth. These estimated critical Hth (λ) value agreed well with the experimentally measured value. Using these simple critical distance stress approach we estimated the fatigue strength of general stress concentration structures such as, round hole, elliptical hole, V notch and contact edge structures. Then these critical distance stress approaches are applied to estimate the size effects of structures. And the eligibility of these estimated results are confirmed by comparing these estimated results with the experimental results. Finally these estimated results and experimental results are compared with the estimated results by other researchers such as, Neuber, Siebel, Ishibashi and Heywood. And we can confirm the superiority of this critical distance stress approach.

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