MATERIAL CONSTANTS IDENTIFICATION COMPOSITE STRUCTURES

• Main Authors: WTWANG, 王文庭
• Other Authors: T. Y. KAM
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/84179988213169077428

博士 === 國立交通大學 === 機械工程系 === 88 === Composite laminates have been used extensively in the mechanical and aerospace industries for fabricating high performance structures. To ensure high reliability of the structures, the actual behaviors of the laminated composite parts in service must be accurately predicted and carefully monitored. It has also been pointed out that accurate determination of current stiffness or material properties of a laminated composite structure can help prevent sudden failure of the structure. The attainment of the actual behavioral predictions of the structures depends on the correctness of the elastic constants of the structures. Therefore, the determination of realistic material or mechanical properties of laminated composite components has become an important topic of research. In this paper, a method for nondestructive evaluation of elastic constants of composite structures is presented. An error function is established to measure the differences between the theoretically and experimentally predicted system deformations and/or natural frequencies. The identification of the elastic constants is formulated as a constrained minimization problem in which the elastic constants are determined to make the error function a global minimum. A global minimization method together with an appropriate bounding technique for constraining the variations of the elastic constants are used to solve the above minimization problem. The applications of the proposed method are demonstrated by means of several examples on the elastic constants identification of laminated composite plates.