Experimental Evaluation of Composite Helical Springs

Author: Ali Hadi A Alshahrani

Alshahrani, Ali Hadi A, 2023 Experimental Evaluation of Composite Helical Springs, Flinders University, College of Science and Engineering

Terms of Use: This electronic version is (or will be) made publicly available by Flinders University in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. You may use this material for uses permitted under the Copyright Act 1968. If you are the owner of any included third party copyright material and/or you believe that any material has been made available without permission of the copyright owner please contact copyright@flinders.edu.au with the details.


Helical springs made of composite material such as glass fibre, carbon fibre, and glass-carbon fibre have an increasing interest in automobile industries and manufacturing of machines where absorption of impact forces is regular scenario. Being lightweight with comparable mechanical strengths (e.g., high-strength, flexibility, and stiffness) like steel helical springs, helical springs made of the lightweight composites (glass fibre/ carbon fibre/ glass-carbon fibre) have been promoted in the industries over conventional steel/ stainless steel-based helical springs. The demand of an alternative of steel in spring manufacturing is not only because of the reduction of weight, but also, to increase efficiency. Hence, an alternative composite material has been using glass fibres, and glass-carbon fibres that has comparatively similar elastic property like steel, but its density is less than steel. Therefore, a helical spring made of this composite material was expected to have comparatively similar pseudoelastic response. This research has investigated the compression stiffness of four different type of helical springs. The variations adopted in the experiments consist of types of composite materials (glass fibre reinforced polymer, and glass-carbon fibre reinforced polymer), and differences in number of coils in the same free length (i.e., pitches). The compression load was applied to the springs up to 450 N with a consistent rate (deformation control). The springs were kept in a corrosion chamber for 48 hours where the salt spray method was used to generate a corrosion environment. The wet and dry automatic cycle was applied through a controller. The springs were again tested by applying compression load with the same speed rate. The stiffnesses at two phases such as rising of initial compression load and rising of compression load after 48 hours of salt spraying were estimated. The glass-carbon fibre-reinforced polymer-based springs had insignificant change in stiffness compared to glass-fibre-reinforced polymer-based springs after applying salt spray. The spring with smaller number of coils had less stiffness than that of the spring with higher number of coils, i.e., spring with larger pitch had less stiffness.

Keywords: experimental, evaluation, composite, helical, springs

Subject: Engineering thesis

Thesis type: Masters
Completed: 2023
School: College of Science and Engineering
Supervisor: Professor Youhong Tang