Fine-tuning Nonlinear Finite Element Analysis Methodology for Aircraft Seat Certification using Component Level Testing and Validation

Abstract

Finite element analysis (FEA) has become a part of new development in automotive as well as in aircraft seating industries. The goal of the FEA in product development is not only to design but to substantiate the certification tests or possibly replace the certification tests. The case of a certification by substantiation tests increases the necessity of validation of the Finite Element (FE) model. In the aircraft industry, the seating Advisory Circular (AC) 20-146 specifies a methodology for the dynamic seat, Certification By Analysis, for use in the Parts 23, 25, 27 and 29 airplanes and rotorcraft. In FE modeling of typically nonlinear environments such as the aircraft dynamic seat simulations, input parameters such as material model, element type, time step scale factor, element length, material model etc. play a vital role in the accuracy of the results. Selecting appropriate material models and other parameters leads to improved accuracy in the FE model and hence to validation with the experimental test results. The purpose of this study is to fine-tune non-linear FEA methodology for aircraft seat certification using component level testing and validation. For this purpose, the effects of input parameters such as the material model, element length, and time step scale factor are evaluated using component test-FE simulation on static tension test on aluminum, high speed load-deflection test on seat cushion and belt pull test. Verification of FE input parameters is determined in each case. Appropriate input variables are selected and provided to an aircraft seat FEA case study and validated against sled test results to demonstrate the validity of the finite element models.