|Title:||Finite Element Modeling and Free Vibration Analysis of Single and double Delamination Composite Beams|
|???metadata.dc.contributor.*???:||Leul Fisseha (PhD)|
Zewdu Abdi (PhD) Co- -Advisor
|Keywords:||Vibration Analysis;Delamination Composite Beams;Finite Element Modeling|
|Abstract:||The requirement for accurate analysis tools to predict the behaviour of delaminated composites has grown and will continue to grow into the future, due to the high demand of these materials on major structural components. In the following, a detailed analysis of single and doubledelaminated beams is made, using traditional finite element techniques, as well as two dynamic element-based techniques. The Dynamic Stiffness Matrix (DSM) and Dynamic Finite Element (DFE) techniques introduce the concept of frequency-dependent stiffness matrices and shape functions, respectively, and have been documented to exhibit excellent convergence qualities when compared to traditional finite elements. Current trends in the literature are critically examined, and insight into different types of modeling techniques and constraint types are introduced. In particular, the continuity (both kinematic and force) conditions at delamination tips plays a large role in each model’s formulation. In addition, the data previously available from a commercial finite element suite are also utilized to validate the natural frequencies of the systems analyzed here. Beam element-based techniques are used and the results are compared to those obtained using the dynamic element techniques and data from the literature. In each case, excellent agreement between different techniques was observed. In addition, The Commercial Software (ANSYS ® 12) based on FEM modeling approach analyzed here is general and accurately predicts delamination effects on the frequency response of beam structures. Based on an existing one-dimensional model, the investigation is extended to two-dimensional modeling for single and double-delamination cases. In each case, clamped-clamped and cantilevered delaminated composite beam configurations, both centered and none-centered delamination conditions are studied. The three-dimensional model is also developed for single delamination of a clamped-clamped delaminated composite beam. The results that obtained from simulations (ANSYS ® 12) are excellent agreement with the data available in the literature. Finally, conclusion, recommendation and future works are made on the usefulness of the presented theories, and some comments are made on the future work of this research path.|
|Appears in Collections:||Thesis - Mechanical Design Engineering|
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