ISO 23930:2023

Overview - ISO 23930:2023 (pultruded FRP compressive test)

ISO 23930:2023 specifies a standardized full‑section compressive test to determine compressive properties of pultruded fibre‑reinforced plastic (FRP) profiles. The method is applicable to pultruded FRP regardless of fibre or resin type and is intended to evaluate the mechanical behaviour of the complete cross‑section (rather than only coupons). The standard notes that full‑section results are often lower than coupon tests but better represent real member performance and are therefore recommended for strength design of pultruded FRP compressive members.

Key topics and technical requirements

• Test principle: Uniaxial compression of the full pultruded profile section using a universal test machine; stress from applied force, strain from gauges/extensometers.
• Apparatus: Test machine compliant with ISO 7500‑1 and ISO 9513; force measurement Class 1. Parallel, well‑guided compression platens at least 5 mm larger than specimen; platen hardness ≥ 700 HV 0,2; surface roughness ≤ 6.3 µm (ISO 21920‑2).
• Strain measurement: Use strain gauges (grid length > 3 mm; k‑factor accuracy ≤ 1%). Gauges positioned according to cross‑section.
• Specimen geometry & limits: Cross‑sections include I, C, L, rectangular, circular, etc. Slenderness ratio < 3; width‑to‑thickness limits (free side plates < 5; plates without free edges < 8; non‑double symmetrical sections < 5). End platens contact faces must be parallel (parallelism error < 0.5 mm).
• Specimen prep & sampling: Minimum 3 specimens (5 recommended). Ends may be reinforced with bonded metal plates (reinforcement length < 1/3 specimen length). Use cutting methods that do not alter material properties (diamond blade, water jet).
• Conditioning & atmosphere: Follow ISO 291 Class 2; preferred (23 ± 2) °C, (50 ± 10) % RH; record temperature and humidity.
• Test speed & measurements: Compression speed v = 0.1 × h (mm/min) where h = specimen length. Dimensional accuracy per ISO 16012 (±0.1 mm for >10 mm; ±0.01 mm for ≤10 mm).
• Results & calculations: Full‑section compressive strength σc = Fc / A. Compressive modulus can be calculated by chord slope (e.g., between 0.05% and 0.25% strain) or regression slope. Record failure mode.

Applications - practical use of the standard

• Structural design and verification of pultruded FRP members (beams, columns, profiles) where full‑section behaviour is critical.
• Product development, quality control and material specification for pultrusion manufacturers.
• Performance comparison for different pultruded profile geometries, fibre/resin systems and manufacturing processes.
• Use in codes and component design where representative full‑section compressive properties are required.

Who should use this standard

• Pultrusion manufacturers, composite material engineers, structural designers, testing laboratories, and standards committees involved in FRP design and certification.

Related standards

• ISO 291 (conditioning), ISO 7500‑1 (test machine calibration), ISO 9513 (extensometer calibration), ISO 16012 (dimensional measurement), ISO 21920‑2 (surface texture).