Overview
EN ISO 26203-1:2025 - "Metallic materials - Tensile testing at high strain rates - Part 1: Elastic-bar-type systems" specifies methods and guidance for determining stress–strain behaviour of metallic sheet materials under high strain‑rate tensile loading using elastic‑bar‑type apparatus. The standard addresses dynamic testing conditions that go beyond quasi‑static methods and is particularly relevant for applications such as vehicle crashworthiness where material strength and strain‑rate sensitivity at rates up to around 10^3 s−1 are important.
Key topics and technical requirements
- Scope and strain‑rate range: Covers high strain‑rate tensile testing (document text refers to strain rates above 10 s−1 and notes applicability to rates commonly encountered in crash analysis). It is intended for elastic‑bar‑type measurement systems.
- Elastic‑bar‑type system principle: Uses a long elastic bar as the force‑measuring device so that reflected elastic waves do not corrupt the force measurement during the short test duration. This contrasts with short force‑measuring devices in servo‑hydraulic systems.
- Apparatus and calibration: Requirements for apparatus design, force measurement bars, and calibration procedures (including displacement measuring devices and signal conditioning) to reduce noise and wave‑reflection artefacts.
- Test piece geometry and preparation: Guidance on test‑piece shape, gauge length, parallel section, shoulders and fillets tailored for dynamic equilibrium and to minimise stress inhomogeneity. Dynamic specimens are typically different from quasi‑static specimens.
- Measurement and data acquisition: Emphasis on high‑speed, low‑inertia or non‑contact displacement measurement (optical/laser) and correct treatment of wave propagation data to compute bar end displacement and stress–strain curves.
- Procedure, evaluation and reporting: Detailed steps for mounting, loading, recording, calibration checks, evaluation of dynamic stress–strain curves and required test‑report contents.
- Annexes: Informative examples including quasi‑static comparison (Annex A), a one‑bar method (Annex B) and the split Hopkinson bar (SHB) method (Annex C).
Applications and users
- Primary users: Materials testing laboratories, automotive crashworthiness engineers, materials scientists, quality and R&D teams in metals and automotive industries.
- Practical uses: Characterising strain‑rate sensitivity for finite element crash simulations, validating constitutive models, materials selection for impact resistance, and forensic/qualification testing of sheet metals.
Related standards
- ISO 26203 series (other parts, e.g., servo‑hydraulic and other systems)
- ISO 6892‑1 and ISO 7500‑1 (quasi‑static tensile and testing machine requirements - referenced for low strain‑rate testing)
- Relevant test‑method literature: one‑bar and split Hopkinson bar techniques (illustrated in annexes)
Keywords: tensile testing, high strain rate, elastic‑bar‑type system, split Hopkinson bar, metallic sheet materials, stress–strain characteristics, vehicle crashworthiness, dynamic testing, calibration.
