Globally robust approximated behavior for the optimum design of composite plates /
Laminated plates have increasingly been used in many different applications for the last three decades. This increased use of laminated plates has prompted researchers to investigate newer methods of designing laminated plate through the utilization of optimum design ideas. However, the complicate...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1995.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=742818511&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Laminated plates have increasingly been used in many different applications for the last three decades. This increased use of laminated plates has prompted researchers to investigate newer methods of designing laminated plate through the utilization of optimum design ideas. However, the complicated mechanical behavior of laminated plates and the cost of performing finite element analysis lead researchers to incorporate approximated behavior models into optimization of laminated plates. Most of these models are local in nature (i.e., based on the first order Taylor series expansion). The accuracy of a local approximation often deteriorates drastically as the design point moves away from the point where the approximation was constructed. Therefore, finite element analyses are needed during optimization to reconstruct another local approximation whenever the design point moves into a new locality of the design space. In this research, globally approximated behavior models to predict deflection, stress resultants, and mid-plane strains and curvatures at points on a laminated plate were constructed, tested and used in several problems of optimum design of laminated plates. Global approximation is a robust explicit expression that predicts the behavior- of laminated plates over all (or most) of the domain of the design space. Thus, no finite element analyses are needed during optimization because the accuracy of the model is independent of position of the design point in tile design space. Several functional forms of the global approximated model -,were obtained using symbolic manipulation. Then, curve-fitting procedures were used to solve for the unknown coefficients in these forms. The responses used in curve-fitting were obtained using a certain number of finite element analyses. Several performance criteria were applied to the functional forms to select the best of them. The approximate model can predict large responses with a typical error of 5%. Moreover, the approximate model and FEA were used in seven optimization examples and predicted similar designs except where small stress values control the design. The approximated behavior model expressions proposed in this research are dependent oil boundary conditions, type of loading, type of material, and the shape of the plate. |
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| Item Description: | Vita. "Major Subject: Civil Engineering". |
| Physical Description: | xv, 207 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |