Interlaminar Stresses in Composite Laminates Subjected to Anticlastic Bending Deformation

2013 ◽  
Vol 80 (4) ◽  
Author(s):  
Johnathan Goodsell ◽  
Nicholas J. Pagano ◽  
Oleksandr Kravchenko ◽  
R. Byron Pipes
Keyword(s):  
Boundary Layer ◽  
Temperature Change ◽  
Plate Theory ◽  
Finite Width ◽  
Uniform Temperature ◽  
Interlaminar Stresses ◽  
Poisson Effect ◽  
Bending Deformation ◽  
Axial Extension ◽  
Deformation State

Approximate elasticity solutions for prediction of the displacement, stress, and strain fields within the m-layer, symmetric and balanced angle-ply composite laminate of finite-width and subjected to uniform axial extension and uniform temperature change were developed earlier by the authors. In the present paper, the authors have extended these solutions to treat bending deformation. Bending and torsion moments are combined to yield a deformation state without twisting curvature and with transverse curvature due only to the laminate Poisson effect. This state of deformation is termed anticlastic bending. The approximate elasticity solution for this bending deformation is shown to recover laminated plate theory predictions at interior regions of the laminate and thereby illustrates the boundary layer character of this interlaminar phenomenon. The results exhibit the anticipated response in congruence with the solutions for uniform axial extension and uniform temperature change, where divergence of the interlaminar shearing stress is seen to occur at the intersection of the free edge and planes between lamina of +θ and –θ orientation. The analytical results show excellent agreement with the finite-element predictions for the same boundary-value problem and thereby provide an efficient and compact solution available for parametric studies of the influence of geometry and material properties. Finally, the solution was exercised to determine the dimensions of the boundary layer in bending for very large numbers of layers.

Interlaminar Stresses in Composite Laminates Subjected to Twisting Deformation

2017 ◽  
Vol 84 (10) ◽  
Author(s):  
Johnathan Goodsell ◽  
Bo Peng ◽  
R. Byron Pipes ◽  
Wenbin Yu
Keyword(s):  
Composite Laminates ◽  
Load Transfer ◽  
Interlaminar Stresses ◽  
Thermoelastic Deformation ◽  
Interlaminar Stress ◽  
Bending Deformation ◽  
Axial Extension ◽  
The Cross ◽  
Twisting Deformation

The interlaminar stress in angle-ply and cross-ply composite laminates subjected to twisting deformation are investigated. Two mechanisms of interlaminar load transfer have been developed by studying the angle-ply laminate and the cross-ply laminate subjected to uniform axial extension, thermoelastic deformation and anticlastic bending deformation. In the present, these mechanisms are investigated in laminates subjected to twisting deformation. It is shown that the mechanisms of interlaminar load transfer in twisting deformation are identical to those previously investigated, though they arise from different causes. Furthermore, a unified treatment of the mechanisms of interlaminar load transfer is presented for the angle-ply laminate and the cross-ply laminate subjected to the four aforementioned modes of deformation.

Comparison of Inviscid Computations With Theory and Experiment in Vibrating Transonic Compressor Cascades

1990 ◽  
Author(s):  
G. A. Gerolymos ◽  
E. Blin ◽  
H. Quiniou
Keyword(s):  
Boundary Layer ◽  
Plate Theory ◽  
Strong Shock ◽  
Acoustic Resonance ◽  
Boundary Layer Separation ◽  
Computational Method ◽  
Viscous Effects ◽  
Transonic Compressor ◽  
Boundary Layer Interaction ◽  
Interaction Regions

The prediction of unsteady flow in vibrating transonic cascades is essential in assessing the aeroelastic stability of fans and compressors. In the present work an existing computational code, based on the numerical integration of the unsteady Euler equations, in blade-to-blade surface formulation, is validated by comparison with available theoretical and experimental results. Comparison with the flat plate theory of Verdon is, globally, satisfactory. Nevertheless, the computational results do not exhibit any particular behaviour at acoustic resonance. The use of a 1-D nonreflecting boundary condition does not significantly alter the results. Comparison of the computational method with experimental data from started and unstarted supersonic flows, with strong shock waves, reveals that, notwithstanding the globally satisfactory performance of the method, viscous effects are prominent at the shock wave/boundary layer interaction regions, where boundary layer separation introduces a pressure harmonic phase shift, which is not presicted by inviscid methods.

Experience of validation and tuning of turbulence models as applied to the problem of boundary layer separation on a finite-width wedge

2016 ◽  
Vol 56 (6) ◽  
pp. 1020-1033 ◽  
Author(s):  
A. A. Babulin ◽  
S. M. Bosnyakov ◽  
V. V. Vlasenko ◽  
M. F. Engulatova ◽  
S. V. Matyash ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Turbulence Models ◽  
Boundary Layer Separation ◽  
Finite Width ◽  
Layer Separation

Modeling of anisotropic boundary layer effects in plate theory

PAMM ◽  
2018 ◽  
Vol 18 (1) ◽  
Author(s):  
Patrick Schneider ◽  
Reinhold Kienzler
Keyword(s):  
Boundary Layer ◽  
Plate Theory

Effect of Bond Layer on Bimaterial Assembly Subjected to Uniform Temperature Change

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
D. Sujan ◽  
Dereje E. Woldemichael ◽  
M. V. V. Murthy ◽  
K. N. Seetharamu
Keyword(s):  
Temperature Change ◽  
Research Work ◽  
Interfacial Stress ◽  
Thin Plates ◽  
Rational Basis ◽  
Uniform Temperature ◽  
Stress Evaluation ◽  
Numerical Example ◽  
Bond Layer ◽  
Shear Compliance

When two thin plates or layers are bonded together, an extremely thin bond layer of third material exists between the two layers. This research work examines the effect of bond layer on the interfacial shearing and peeling stresses in a bimaterial model. Earlier papers on this topic are based on several mutually contradictory expressions for the shear compliance of the bond layer. This paper is aimed at resolving this ambiguity and presents derivation of shear compliance on a rational basis. A numerical example is carried out for a silicon-copper system with a gold-tin solder bond layer. The results obtained are likely to be useful in interfacial stress evaluation and physical design of bimaterial assemblies used in microelectronics and photonics applications.

Die Cracking at Solder (In60-Pb40) Joints on Brittle (GaAs) Chips: Fracture Correlation Using Critical Bimaterial Interface Corner Stress Intensities

2003 ◽  
Vol 125 (3) ◽  
pp. 369-377 ◽  
Author(s):  
Bingzhi Su ◽  
Y. C. Lee ◽  
Martin L. Dunn
Keyword(s):  
Stress Intensity ◽  
Temperature Change ◽  
Failure Criterion ◽  
Critical Stress ◽  
Solder Bump ◽  
Bimaterial Interface ◽  
Uniform Temperature ◽  
Elastic Fields ◽  
Solder Bumps ◽  
Wide Range

We study cracking from the interface of an In60-Pb40 solder joint on a brittle GaAs die when the joint is subjected to a uniform temperature change. Our primary objective is to apply and validate a fracture initiation criterion based on critical values of the stress intensities that arise from an analysis of the asymptotic elastic stress fields at the interface corner. In some regards the approach is similar to interface fracture mechanics; however, it differs in that it is based on a singular field other than that for a crack. We begin by determining the shape that the solder bump will assume after reflow when constrained by a fixed diameter wetting pad on the GaAs. To simplify the interpretation of the results, we focus on a class of solder bumps of various sizes, but with a self-similar shape. The approach, though, can be applied to different size and shape solder bumps. We then compute the asymptotic interface corner fields when the system is subjected to a uniform temperature change. The asymptotic structure (radial and angular dependence) of the elastic fields is computed analytically, and the corresponding stress intensities that describe the scaling of the elastic fields with geometry and loading are computed by axisymmetric finite element analysis. In order to assess the validity of fracture correlation using critical stress intensities, we designed and fabricated a series of test structures consisting of In60-Pb40 solder bumps on a GaAs chip. The test structures were subjected to uniform temperature drops from room temperature to induce cracking at the interface corner. From the tests we determined the relationship between the solder bump size and the temperature change at which cracking occurred. Not unexpectedly, smaller bumps required larger temperature changes to induce cracking. The observed scaling between solder bump size and temperature change is well described by the critical stress intensity failure criterion based on only a single parameter, the critical value of the mode 1 stress intensity, K1crn. Interestingly, this is because over a significant region, the mode 2 and constant terms in the asymptotic expansion cancel each other. This failure criterion provides the necessary machinery to construct failure maps in terms of geometry and thermomechanical loading. We conclude by describing how to apply the approach in more general and more practical settings that are possibly applicable to a wide range of problems in microelectronics, optoelectronics, and microelectromechanical systems packaging.

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