What Is a Tensile Tester?
A tensile tester is a device that measures the response of a material sample under a tensile load. It evaluates mechanical properties such as tensile stress, strain, Young’s modulus, and Poisson’s ratio, crucial in determining the strength and durability of products.
Uses of Tensile Testers
Tensile testers are essential for assessing the mechanical properties of various materials like metals, plastics, rubbers, and fibers. They are also used in biological studies for testing the strength of tissues such as muscle and bone and in evaluating medical device materials.
Principle of Tensile Testers
Tensile testers operate by applying a tensile load to a specimen and measuring the resulting stress and strain. Key parameters like the proportional limit, elastic limit, yield point, and tensile strength are calculated from the stress-strain curve. The early measurement stage shows proportionality between stress and strain, the mid-term includes the elastic limit and yield point, and the final rupture indicates the sample’s tensile strength.
Types of Tensile Testers
Common types of tensile testers include hydraulic and mechanical universal testing machines:
- Hydraulic Universal Testing Machine: Performs various static tests by adjusting stress through hydraulic pressure.
- Mechanical Universal Testing Machine: Known for constant speed testing using servo motors.
Other Information on Tensile Testers
Key aspects of tensile testers include:
-
- Units: Stress is measured in Newtons (N), with mN or kN used for different load cell capacities. Before SI units’ enforcement, “kgf” was used, but it has been replaced by “N” in modern standards.
- Young’s Modulus: Indicates material hardness, with higher values denoting harder, less bendable materials. Steel, for instance, has a high Young’s modulus.
- Poisson’s Ratio: The ratio of longitudinal to transverse strain, with a value near 0.5 indicating no volume change during deformation, typical for materials like rubber.
- JIS Standards: There are various JIS standards for tensile testing, tailored to different materials. Adherence to these standards ensures fair and standardized test results.