Computational Modal Analysis of Half Scale Business Jet Fuselage Tail Section

Abstract

Abstract Acoustic noise caused by structural vibrations directly affect the comfort of passengers on aircrafts throughout the duration of their flight., The dynamic characteristics of a system that dictate the behavior of such vibrations is critical to the improvement of flight conditions. Modal analysis is the practice of determining these dynamic characteristics of a structure under loading [1]. A computational modal analysis was conducted in this study with the objective of validating the previous experimental modal analysis, and providing a reliable model that can predict accurate frequency responses based on future modifications to the structure. This paper focuses on the development, validation and preliminary comparisons of the computational modal analysis. The mode shapes and natural frequencies were analyzed and validated for connectivity. The Frequency response curves for all measured points showed repeatability for the tests. Modal Assurance Criterion was measured against the data that demonstrated good similarity in mode shapes. A preliminary comparison was done between the experimental and computational data that compared differences between natural frequencies in correlated mode pairs, which were minimal. It was found that the model is underdamped in comparison to the experimental model. The next stage of this work is determined to be iteratively finding these damping values, then doing a comparison with the experimental data using a pseudo orthogonality check.