• Structural Engineering and Mechanics
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• v.88 no.4
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• pp.369-377
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• 2023

In this study, previously developed algorithm is used for Optimization of hybrid composite plates using Tsai-Wu criteria. For the stress-based Design Optimization problems, Von-Mises stress uses as design variable for isotropic materials. Maximum stress, maximum strain, Tsai Hill, and Tsai-Wu criteria are generally used to determine failure of composite materials. In this study, failure index value is used as design variable in the optimization algorithm and Tsai-Wu criteria is utilized to calculate this value. In the analyses, commonly used design domains according to different hybrid orientations are optimized and results are presented. When the optimization algorithm was applied, 50% material reduction was obtained without exceeding allowable failure index value.

• Composites Research
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• v.15 no.2
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• pp.1-10
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• 2002

The strength of glass/epoxy fabric joints under pin-loading is estimated based on the characteristics length method and experiment. To investigate the effect of finite element idealization for the contact between pin and laminate, three modeling cases are analyzed; assuming the cosine load distribution around the contact area, constraining the radial displacement at the hole boundary, and using the contact element. To study the effect of failure criteria, Tsai-Wu and Yamada-Sun methods are applied on the characteristic curve. The results of the nonlinear analysis using the contact element showed good agrements with experimental data in both laminates made of uni-directional prepreg tapes and fabrics. In terms of failure criteria, Tsai-Wu method showed better agreement with experimental results than the one by Yamada-Sun laminate.

• Composites Research
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• v.31 no.6
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• pp.340-346
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• 2018

This paper addresses the stress analysis and design of composite double lead spiral which is boarded in 20mm universal ammunition drum by finite element method. The spiral system is very important to transfer the ammunition in stable and reliable manners for aircraft. Some verifications are done to check the possibility of composite application in spiral system. The design variables, stacking sequence and fiber orientation angles, are investigated for reliable design for practical design. The Tsai-Wu failure theory is applied to see the safety of the spiral structure. The design result is suggested to manufacture the double lead spiral part.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.717-720
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• 1999

Recently, the fiber composite materials such as carbon fiber, glass fiber, or aramid, have been frequently used in strengthening reinforced concrete structures. The fiber composite materials typically have orthotropic characteristic and the strength changes significantly acording to the direction of fibers and the method of the lamination. In this study, an algorithm to estimate the stress-strain relationship of the composite materials which have different fiber directions and symmetric or non-symmetric lamination has been developed by using Tsai-Hill and Tsai-Wu failure criteria and progressive laminate failure theory. This algorithm has been implemented to several stress-strain models for the laterally confined concrete compression members such as Mander, Hosotani, and Nakatsuka. The evaluated stress-strain behaviors by the different models are discussed.

• Computational Structural Engineering : An International Journal
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• v.1 no.1
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• pp.39-48
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• 2001

An analytical compressive stress-strain relationship model for circular and rectangular concrete specimens confined with laminated carbon fiber sheets (CFS) is studied. Tsai-Hill and Tsai-Wu failure criteria were used to implement orthotropic behavior of laminated composite materials. By using these criteria, an algorithm which analyzes the confinement effect of CFS on concrete was developed. The proposed analytical model was verified through the comparison with experimental data. Various parameters such as concrete strength, ply angle, laminate thickness, section shape, and ply stacking sequences were investigated. Numerical results by the proposed model effectively simulate the experimental compressive stress-strain behavior of CFS confined concrete specimens. Also, the pro-posed model estimates the compressive strength of the specimen to a high degree of accuracy.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.10a
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• pp.187-190
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• 2001

Response surface method is applied to evaluate the reliability of laminated composite panels. Since the linear and nonlinear first-ply failure load are computed using deterministic finite element analysis, new probabilistic finite element analysis is not necessary. Tsai-Wu criterion is used to construct the limit state suface. Material properties, layer thickness and lamina strengths of laminated composite panel are treated as random design variables. feasibility and accuracy of current method is validated using Monte-Carlo method Which perform thousand times of finite element analysis directly.

• Journal of the Korean Statistical Society
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• v.21 no.1
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• pp.35-46
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• 1992

On Box-Cox transformation, one or few responses are influential on transformation parameter estimator. To detect influential observatins, several diagnostics (Cook and Wang 1983, Hinkley and Wang 1988, Lawrance 1988, Tsai and Wu 1990) have been suggested. We compare these diagnostics and denote the necessity of multiple cases deletion which is important especially when the masking effect is present. Also, analytic expression of Tsai and Wu's diagnostic is given. We suggest a computationally feasible and useful algorithm based on the basic building blocks, and present descriptive examples using artificial data.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.3
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• pp.219-226
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• 2005

In this study, the problem formulation and solution technique using genetic algorithms for design optimization of laminate composite cylindrical beam section are presented. The hollow cylindrical beams we usually used in the wheel chair. If the weight of wheel chair is reduced, it will lead to huge improvement in passenger's mobility and comfort. In this context, the replacement of steel by high performance and light weight composite material along with optimal design will be a good contribution in the process of weight reduction of a wheel chair. An artificial genetics approach for the design optimization of hollow cylindrical composite beam is presented. On applying the genetic algorithm, the optimal dimensions of hollow cylindrical composite beams which have equivalent rigidities to those of corresponding hollow cylindrical steel beams are obtained. Also structural analysis is conducted on the entire wheel chair structure incorporating Tsai-Wu failure criteria. The maximum Tsai-Wu failure criteria index is $0.192\times10^{-3}$ which is moth less than value of 1.00 indicating no failure is observed under excessive loading condition. It is found that the substitution of steel by composite material could reduce the weight of wheel chair up to 45%.

• Journal of Aerospace System Engineering
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• v.12 no.2
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• pp.66-75
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• 2018

In this paper, a lightweight design of the spar cap of 2MW wind turbine blade was carried out using the ply reduction ratio (PRR) and CFRP with a trade-off study. The spar cap is one of the most critical factor in determining the mechanical performance of the blade. Tsai-Wu and Puck fracture theory were used to determine the fracture. As a result, the CFRP composite material could be lighter in terms of weight by about 30% than GFRP composite material under the same conditions. Based on the analytical results, we derive the optimal value of the laminate thickness of the composite material and present the structural performance improvement and the lightweight design result.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.05a
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• pp.163-167
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• 2001

A two-dimensional progressive failure analysis method is presented for the strength characterization of the composite joints under pin loading. The eight-nodes laminated she]1 element is utilized based on the updated Lagrangian formulation. The criteria by Yamada-Sun, Tsai-Wu, and the maximum stress are used for the failure estimation. The stiffness of failed layer is degraded by the complete unloading method. No factor depending on test is included in the finite element analysis except for the material strength and stiffness. Total 20 plate specimens with and without hole are tested to validate the finite element prediction. The Tsai-Wu failure criterion most conservatively estimates the strength of laminate, and the maximum stress criterion yields the highest strength because it does not consider the coupling of the failure modes. The strength by Yamada-Sun method neglecting the matrix failure effect are located between other two methods and shows best agreement with test result for laminate with hole.