Dynamic Sensitivity Analysis of a Free-Free Aluminum Beam Under Transient Multi-Point Impact Excitation Using Experimental Modal Analysis, Numerical Simulation, and Analytical Modeling

Karimi, Mehrdad; Javadi, Masoud

doi:10.22060/mej.2026.24330.7861

Dynamic Sensitivity Analysis of a Free-Free Aluminum Beam Under Transient Multi-Point Impact Excitation Using Experimental Modal Analysis, Numerical Simulation, and Analytical Modeling

Document Type : Research Article

Authors

mehrdad karimi ¹

Masoud Javadi ²

¹ Aerospace, Faculty of Postgraduate Studies, Shahid Sattari University, Tehran, Iran

² Assistant Professor, Faculty of Aerospace, Shahid Sattari University, Tehran, Iran

10.22060/mej.2026.24330.7861

Abstract

Dynamic analysis plays a crucial role in predicting the vibrational behavior of structural systems. This study aims to accurately extract the modal characteristics of a free-free aluminum beam through a synergistic integration of experimental, analytical, and numerical approaches. In the experimental phase, calibrated modal hammer tests were conducted at six nodal positions, and the dynamic responses were captured using precision signal analyzers. The acquired data were processed in the specialized Star software using advanced signal processing algorithms to extract modal parameters with minimal systematic error. In the analytical phase, a mathematical model based on the governing differential equations of elastic structures—accounting for structural damping—was developed in MATLAB. Natural frequencies and mode shapes were identified using Peak Picking and Circle Fitting techniques. Additionally, finite element analysis was carried out in Abaqus, utilizing fine rectangular meshing and high-order hexahedral elements, which demonstrated excellent performance in simulating the system’s vibrational behavior under resonant conditions. Comparison of the results showed strong agreement in the frequency range of 0 to 1700 Hz, with deviations of less than 0.01% when considering the first mode as a rigid-body mode. This study highlights the importance of selecting appropriate excitation points to ensure accurate modal identification and confirms the proposed framework’s potential for analyzing more complex engineering structures.

Keywords

modal analysis

impact excitation

Natural frequency

frequency response matrix

Subjects