Free vibration of multiple delaminated beams with step changes in cross-section

• Main Author: Liew, Jia Hong.
• Other Authors: Shu Dong Wei
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Mechanical engineering::Mechanics and dynamics
• Online Access: http://hdl.handle.net/10356/54078
• Institution: Nanyang Technological University

In this project, the study of the free vibration of multiple delaminated beams with step changes in cross-section is conducted through analytical solutions. Analysis of the homogeneous laminates is performed using the method of Region Approach, such that the delaminated beam is modelled as smaller Euler-Bernoulli beam portions. In addition, only the vibration analysis of the delaminated beams, under ‘free mode’ assumption is considered. For this analysis, the delaminations are specified to be non-overlapping, and they share equal length. Three cases will be examined in this report: (i) one-delamination-one step, (ii) two delaminations-one step, (iii) three delaminations-two steps. The delaminations and step change interfaces are used as boundaries which divide the multiple delaminated and step changed beams into five, eight and twelve portions for the three cases indicated respectively. Comparisons of the natural frequencies and delamination lengths results indicated that when there is a change in the delamination lengths, number of delaminations, cross-section area ratio of the step change and location of the delamination from the midplane, it will cause a pronounced effect in the natural frequencies. The analytical results of this study can serve as the benchmark for FEM and other numerical solutions.