Industrial Consultancy & Sponsored Research (IC&SR) , IIT Madras

High Strain Rate Tensile Testing Set-up by Impact Loading

Categories for this Invention

Categories: Automobile & Transportation | Aerospace & Defense Technologies

Industry:  Materials Science and Engineering

Applications: Dynamic Material Behavior Analysis, Crashworthiness Testing Safety, Impact Testing, Materials R&D

Market: Tensile Testing Machine Market was valued nearly US$ 444.05 Mn. in 2022. It is expected to reach at US$ 569.56 Mn By 2029; estimated to grow at a CAGR of 3.62% in the time period from 2022 to 2029.

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Problem Statement

  • Current methods inadequately assess materials under high strain rates, impeding progress in crash-worthy structure design.
  • Existing setups, like Split Hopkinson Pressure Bars, lack coverage for medium strain rates (1-100 s⁻¹), leaving a gap in material behavior.
  • Discrepancies between brittle failure in dynamic tests and ductile failure in quasi-static tests emphasize the need for a more comprehensive testing approach.
  • Traditional machines, including universal testing machines, are unsuitable for high-strain-rate testing, limiting accurate assessments of material responses in dynamic loading conditions.
  • Current setups lack an efficient method to directly convert impact energy into tensile loading, crucial for replicating real-world scenarios, especially in automobile crashes.

Technology

  • The instant technology disclosure refers to the detailed outline of the apparatus, methodology, and outcomes of high strain rate tensile testing, contributing valuable insights in the fields of Materials Science And Engineering.

Apparatus Description:

  • Explanation of the key components, such as the drop mass tower, guide rods, hoist, and dynamic load cell.
  • Details on the fixture design, including the first and second moving discs, fixed discs, and holders for securing the test specimen.

Methodology:

  • Step-by-step procedures for conducting high strain rate tensile testing using the disclosed apparatus.
  • Description of how the drop mass is released at different heights to achieve varying strain rates. Insights in the measurements taken, including impact velocity & load-time history.

Materials Tested:

  • Identification of materials subjected to testing, such as epoxy or glass/epoxy composites.
  • Other polymer-reinforced composites or metals, broadening the applicability of the technology.
  • Mention of the strain rates applied during the experiments, providing a context for results.

Results and Observations:

  • Addressing the need for understanding material behavior under high-speed impacts, especially in industries like automotive and aerospace.
  • Presentation of findings from the experiments, including stress-strain responses and changes in material properties under different strain rates.
  • Highlighting the apparatus’s ability to reveal differences in material behavior under dynamic and quasi-static conditions, crucial for comprehensive analysis.

Discussion on Tensile Properties:

  • Interpretation of the observed trends in tensile modulus, tensile strength, and failure strain at varying strain rates.
  • Possible explanations for the observed changes, such as the influence of the viscoelastic nature of the polymeric matrix.

Key Features / Value Proposition

User perspective:

  • Precise assessment of material responses under dynamic loading conditions.
  • Applicability across various industries, including automotive and aerospace, offering a broad range of testing capabilities.
  • Streamlined testing process with a direct conversion of impact energy to tensile loading, saving time and resources.

Industrial perspective:

  • Facilitates the design of crashworthy structures by providing crucial insights into material behavior under high strain rates.
  • Cost-Efficiency: Optimizes material selection and design processes, reducing the need for extensive physical testing and iterations.
  • Addresses the limitations of existing setups, bridging gaps in medium strain rate testing and offering a more direct and versatile solution for more comprehensive material assessment.

Technology perspective:

  • Unique capability to efficiently convert impact energy into tensile loading for a more realistic simulation of real-world scenarios.
  • Provides in-depth understanding of material behavior under dynamic conditions, contributing to the development of advanced materials.

Questions about this Technology?

Contact For Licensing

sm-marketing@imail.iitm.ac.in
ipoffice2@iitm.ac.in

Research Lab

Prof. Velmurugan R

Department of Aerospace Engineering 

Intellectual Property

  • IITM IDF No.: 1325 

  • IP No.: 468932 (Granted)

Technology Readiness Level

TRL-4

Validated in Laboratory

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