Measuring the elastic properties of fine wire

Area of Science:

• Materials Science
• Biomedical Engineering
• Mechanical Engineering

Background:

• Implantable biomedical devices often utilize fine wires made from MP35N and 304 Stainless Steel (304SS).
• The elastic moduli of these wires are typically assumed to match literature values.
• Manufacturing processes, particularly cold working, can significantly alter material properties like elastic moduli.

Purpose of the Study:

• To experimentally determine the Young's and shear moduli of cold-worked MP35N and 304SS fine wires.
• To compare these experimentally determined moduli with established literature values.
• To assess the impact of cold working on the elastic properties of these critical biomaterial wires.

Main Methods:

• Three distinct experiments were conducted on fine wires of MP35N and 304SS.
• Young's modulus was measured using tensile testing or similar methods.
• Shear modulus was determined through appropriate torsion or shear-based experimental setups.

Main Results:

• Experimentally determined Young's modulus for both MP35N and 304SS wires were significantly lower than reported literature values.
• Experimentally determined shear modulus for both wire types were also significantly lower than literature values.
• Young's modulus showed a maximum deviation of up to 26%, and shear modulus up to 14% from reported values.

Conclusions:

• Cold working significantly reduces the elastic moduli of MP35N and 304SS wires used in biomedical applications.
• The assumption of using standard literature values for elastic moduli is inaccurate for cold-worked fine wires.
• Accurate material property data is crucial for the design and performance prediction of implantable devices utilizing these wires.