ISO 18872:2007 describes procedures used to determine tensile properties of moulding and extrusion plastics across a wide range of strain rates, including high strain rates relevant to impact-type loading.
Instead of relying only on difficult-to-run high-speed tensile measurements, this standard uses measured tensile behavior at lower and moderate strain rates plus mathematical modelling and extrapolation to calculate tensile properties at higher strain rates. If you need help deciding whether ISO 18872 fits your material and reporting needs, talk with our team.
ISO 18872:2007 — Plastics — Determination of tensile properties at high strain rates
ISO 18872 is a plastics tensile-testing standard focused on strain-rate effects. It is commonly referenced when product performance depends on loading speed (for example, rapid deformation events) and when engineers need strain-rate-sensitive tensile inputs for analysis or simulation work.
This document is best understood as a test-and-analysis procedure: it combines measured tensile results at lower rates with curve fitting and extrapolation to derive tensile properties at higher strain rates by calculation.
Quick definition
Standard type: Test method / procedure (tensile property determination with modelling and extrapolation).
Primary purpose: Derive tensile properties at high strain rates for plastics while reducing experimental uncertainty and practical challenges associated with direct high-rate measurements.
Typical outcome: A strain-rate-dependent tensile property set that can be used for engineering comparison and analysis.
What This Standard Covers
ISO 18872 specifies procedures for determining tensile properties of moulding and extrusion plastics over a wide range of strain rates, including high strain rates appropriate to impact-loading situations.
The approach relies on tensile measurements at low and moderate strain rates, mathematical functions used to model the measured results, and extrapolation to obtain parameters at high strain rates. The high strain-rate tensile properties are then calculated from those parameters.
Why This Standard Matters in Testing
For many plastics, tensile response changes significantly with strain rate. When a design case involves rapid loading, relying only on conventional “quasi-static” tensile results can under-represent stiffness and strength under fast deformation.
ISO 18872 provides a structured way to generate strain-rate-sensitive tensile properties while avoiding some of the common pitfalls of direct high-speed testing (such as measurement stability, alignment sensitivity, and high-rate strain measurement challenges).
Common Materials, Product Types, or Applications Covered
This standard is aimed at moulding and extrusion plastics. It is often considered when tensile performance needs to be characterized beyond a single test speed, especially where rapid deformation or dynamic loading is relevant.
Typical use cases: Strain-rate dependent material characterization, comparative evaluation of plastics under faster loading assumptions, and engineering datasets that need tensile behavior over a wide strain-rate range.
Common Test or Verification Workflow
Most implementations follow a practical flow that combines physical tensile testing with analysis.
Common workflows: (1) Run tensile tests at low and moderate strain rates using appropriate plastics tensile specimens and grips, (2) compile stress-strain results and fit the required mathematical model, (3) evaluate rate dependence of parameters, (4) extrapolate to high strain rates, and (5) calculate the corresponding tensile properties at the desired higher strain rates for reporting or downstream engineering use.
Practical note: Because calculated results depend on the strain-rate range tested and the modelling choices permitted by the standard, test planning and reporting expectations should be aligned with the exact edition cited in your requirement.
Equipment Commonly Used for This Standard
ISO 18872 typically points to a conventional tensile testing setup for generating the baseline data (low to moderate strain rates), combined with analysis tools for modelling and extrapolation.
Common equipment: Universal testing machine (electromechanical or servo-hydraulic, as appropriate to the required speed range), suitable tensile grips for plastics, aligned load train, and a strain measurement approach appropriate for plastics (extensometer or validated crosshead-based strain, depending on the requirement).
Data and controls: Test control and data acquisition capable of stable loading at the required strain rates, plus software (or a validated workflow) to perform curve fitting and parameter extrapolation consistent with ISO 18872’s procedure.
If you are selecting a system for strain-rate-sensitive tensile testing and need to compare frame capacity, speed range, grips, and strain measurement options, you can request a detailed quote for a configuration matched to your plastics test workflow.
How to Read This Designation or Revision
ISO 18872:2007 refers to the ISO standard numbered 18872, published in 2007 (Edition 1).
Revision sensitivity: Because this method combines testing and calculation, edition differences can affect modelling steps, parameter definitions, and reporting expectations. For procurement documents or customer specifications, match the year designation exactly as cited.
Related Standards, Methods, or Frameworks when useful
ISO 18872 is focused on tensile properties versus strain rate. In practice, labs often coordinate ISO 18872 work with their existing plastics tensile specimen preparation, tensile test execution procedures, and reporting conventions used for conventional tensile testing.
Good practice: Keep specimen type, strain measurement method, and the strain-rate test matrix consistent with the requirement you are trying to satisfy (customer spec, internal material card, or simulation input format), and document the test speeds and analysis assumptions clearly.
Get help with ISO 18872 testing and equipment selection
Whether you are updating a plastics material characterization program or setting up strain-rate-dependent tensile testing for design data, we can help you align machine speed capability, grips, strain measurement, and data handling with your ISO 18872 requirement. To discuss your application, contact our team.