Experimental investigation about composite bearing strength

Abstract

The bearing investigation on mechanical joints of composite materials is extensive. The main reason for bearing investigation, in a certain aspect, is related to the variability of parameters associated with bearing behavior. In this sense, theoretical and/or experimental studies have been exhaustively conducted. Depending on the solution obtained, there is a cost/benefit relationship for the problem in question. However, in the case of aeronautical applications, an important factor to be considered is the safety, which reflects into safety margin. In this sense, an excess of tests is needed for design that reflects in high cost and time-consuming. Therefore, simpler approaches are necessary in the pre-design phase, where quick answers are required for the initial product definition. In this way, the present work presents composite bearing tests with two distinct environmental conditions, i.e., low-temperature dry (LTD) and room-temperature dry (RTD) in order to show that there is one procedure to simplify the process and gain cost and time. For this, five different configurations specimens with 12 coupons each one were tested in two different environmental conditions. The fastened joint manufactured used protruding fastener, two different diameters (3/16″ and 5/32″) and three laminates (10, 12 and 14 plies). Based on the ASTM D5961 standard, the experimental results showed a linear response not showed in the literature for composite materials. The proposal presented here showed an excellent way to avoid others tests with different conditions, i.e., with different layups and fastener diameters.