Experimental and numerical investigation of impact resistance of riveted and rfssw stringer-stiffened panels in blunt impact tests

Abstract

Aluminium alloy sheets have come into widespread use in the design of stringerstiffened aerospace structures. This paper evaluates experimentally and numerically the response of stringer-stiffened Alclad 7075-T6 aluminium alloy panels subjected to impact loading. The aim of the study was to compare the impact resistance of riveted structures with the structures with the impact resistance of structures welded using the refill friction stir spot welding (RFSSW) process, which is a relatively new technique now used to create joints in aircraft structures. The experimental tests were carried out using a drop-weight type impact testing machine. Finite element modelling of stringer-stiffened panels under impact loading was carried out by using the nonlinear finite element-based MSC.Marc + Mentat program. The results of the numerical computations were validated against the experimental data. Studies were also made of the resistance of the joints to failure, the springback response and the stiffness of joints in the conditions of the dynamic impact test.