VIBRATIONAL ANALYSIS OF HUMAN BODY UNDER SITTING POSTURE : A FEA STUDY

Numerous research efforts have focused on the mathematical modeling of the human body in a seated posture within a vehicle. However, limited work has been dedicated to developing an ellipsoidal model and subsequently conducting modal and frequency response analysis. In this study, an ellipsoidal model was developed, and finite element analysis (FEA) was carried out on a human body in a seated position without a backrest. A 3D ellipsoidal model of the human body was created in SolidWorks using anthropometric data representing the 50th percentile of a 54 kg human, as available in literature. This model was then analyzed and exported to ANSYS Workbench for further analysis. Modal analysis was conducted to determine the natural frequencies of the model, as the human body is particularly susceptible to low-frequency vibrations. The mode shapes at these frequencies were also identified. The natural frequencies obtained from the analysis were compared with existing literature. Additionally, harmonic analysis was performed to calculate the stress values within the human body. The analysis revealed that the maximum stress, amounting to 238.56 MPa, occurred at the joints between different sections of the body. The modal analysis showed that maximum deformation transmits from the legs to the upper body as the natural frequency increases, and this deformation further increases with rising acceleration. Specifically, the highest stress of 238.56 MPa was observed at the joints between the upper and lower legs, and between the upper arm and the upper torso. This study provides valuable insights into the vibrational behavior of the human body in a seated posture, highlighting critical areas of stress and deformation that could inform ergonomic and safety improvements in vehicle seating design. Keywords: Ellipsoidal model, Harmonic analysis, Human body vibration, Mode shapes, Stress distribution.