A novel composite connecting rod: study on mechanical and dynamic behaviour through experimental and finite element approach

Abstract

The increase in strength and stiffness of a metal matrix composite connecting (MMC) rod when compared to conventional rods have motivated researchers in this area. This opens a new window for the present research, here Al7075 alloy and Al7075-based composite connecting rods were fabricated by machining composite blocks using computer numerical control machining centre. Al7075-based composite connecting rods comprises of 91 % Al7075, 3 % hexagonal boron nitride (h-BN) and 6 % of zirconium dioxide (ZrO2). Modal characteristics and mechanical performance of the prepared components were analysed. An experimental modal analysis was conducted on the connecting rod under fixed-free condition to identify the natural frequency and its mode shapes, further the outcomes were compared with the numerical values. The ANSYS workbench is used to estimate the component's failure load based on finite element (FE) approach. The results obtained from modal analysis revealed that the composite connecting rod is more dynamically stable than its unreinforced counterpart. Composite connecting rods also showed better load-bearing capacity as compared to Al7075 in terms of tensile and compressive loading. Failure load analysis results indicate that under compressive load the component bends along the shank (I-beam), while under tensile load, cracks originate at the section connecting the piston pin end and the I-beam. The composite connecting rod sustained 13.5 % higher compressive load and16.5 % higher tensile load than the Al7075 connecting rod, making it a suitable alternative material. The failure mechanisms have been investigated by extensive scanning electron micrography of fabricated connecting rods.

Keywords

• Connecting rod
• Damping
• Modal analysis
• Composite
• Failure analysis