Award Date

5-1-2022

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

First Committee Member

Brendan O'Toole

Second Committee Member

Zhiyong Wang

Third Committee Member

Kwang Kim

Fourth Committee Member

Evangelos Yfantis

Number of Pages

104

Abstract

Helical coil springs are used in many mechanical design applications including industrial machines, devices, and vehicle suspension systems. It is desirable to minimize the weight of vehicle suspension systems as this can improve performance and handling. Most vehicle suspension coil springs are made from solid steel alloys or other metallic materials. Significant weight savings could be achieved if the metallic material were replaced by high performance fiber reinforced polymer composites. However, the coil spring geometry is a difficult manufacturing challenge for composite materials. The goal of this thesis was to investigate efficient and low-cost manufacturing methods to produce light-weight polymer composite springs. Theoretical analysis of carbon fiber-epoxy helical springs was performed to demonstrate that suitable spring performance characteristics could be achieved at a reduced weight compared to steel springs. Multiple manufacturing approaches were attempted to determine a method to effectively produce a helical carbon fiber spring. These processes involve producing a mandrel that acts as an internal tool to lay-up the fiber reinforcement, infuse the epoxy resin, and cure the composite part. Three complete composite springs were fabricated. The springs were initially tested in quasi-static compression to determine the effective spring constant and to determine the reproducibility of these properties between different manufacturing cycles. Compressive fatigue experiments were performed up to 162 cycles to determine if there would be any change in properties. There was a 1% change in spring length and 7% change in spring constant after 167 cycles of loading. The mean spring constant after cycling for the three springs was 221.9 N/cm (126.7 lb/in) with a variance of 1.15 N/cm (0.65 lb/in). The composite springs had a weight reduction of 73.13% when comparing the weight per length to a steel equivalent. Theoretical predictions of the spring constant were accurate to 2% of the experimental results.

Keywords

3D Printing; Additive Manufacturing; Braided Structure; Composite; Helical Springs; Selective Laser Sintering

Disciplines

Aerospace Engineering | Mechanical Engineering

File Format

pdf

File Size

2700 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

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