Overview
ISO 13061-8:2022 is an international standard specifying a precise test method for determining the ultimate strength of small clear wood specimens in shearing parallel to the grain. This standard is part of the ISO 13061 series, focusing on physical and mechanical properties of wood through test methods applied to defect-free small clear specimens. The test assesses the breaking load by applying a static shearing force along the radial or tangential plane, offering key mechanical strength data for wood material characterization, quality control, and research. Updated in 2022, this first edition replaces the older ISO 3347:1976 with technical revisions to improve clarity, specimen preparation, and moisture content adjustments.
Key Topics
- Scope and Purpose: Specifies testing methods for ultimate shearing strength parallel to the wood grain on small clear specimens under static loading.
- Specimen Preparation: Requires sampling according to ISO 3129, with specimen widths and shearing surfaces between 20 mm and 50 mm; testing can be conducted on green (moisture above fibre saturation point) or air-dry conditioned specimens.
- Testing Procedure: Uses a testing machine applying a gradually increasing shearing load at a controlled rate, leading to failure typically within 1 to 5 minutes.
- Measurement and Calculation: Ultimate strength (in N/mm² or MPa) is calculated by dividing the maximum breaking load by the cross-sectional area of the specimen’s shearing plane.
- Moisture Content Adjustment: Results can be adjusted to a standard 12% moisture content using recognized national or international methods to ensure comparability.
- Reporting Requirements: Comprehensive documentation includes sampling details, test conditions, moisture content, density, load direction, testing speed, and any deviations or anomalies.
Applications
Implementing ISO 13061-8:2022 provides essential data for:
- Timber Industry Quality Control: Verifying wood strength properties crucial for structural applications and product grading.
- Material Research and Development: Characterizing wood behavior under shear stresses to optimize applications in construction, furniture making, and composites.
- Engineering and Design: Incorporating accurate wood strength parameters into models and safety assessments for timber structures.
- Regulatory Compliance: Ensuring wood products meet national and international mechanical property requirements through standardized testing methodologies.
- Academic and Laboratory Testing: Facilitating reproducible experiments and comparative studies on different wood species and treatments.
Related Standards
ISO 13061-8:2022 references and aligns with the following related standards to provide a holistic testing framework:
- ISO 3129: Wood sampling methods and general requirements for physical and mechanical testing of small clear specimens.
- ISO 13061-1: Determination of moisture content for physical and mechanical wood tests.
- ISO 13061-2: Determination of density for physical and mechanical wood tests.
- ISO 24294: Timber vocabulary providing essential terms and definitions relevant to wood testing.
- ISO 3347 (1976): The superseded standard for ultimate shearing stress parallel to grain, technically revised by ISO 13061-8.
By adhering to ISO 13061-8:2022, professionals gain consistent, reliable, and internationally recognized procedures to assess the ultimate shearing strength of wood, enabling better quality, safety, and performance in timber applications worldwide.
Open preview (PDF)Physical and mechanical properties of wood — Test methods for small clear wood specimens — Part 8: Determination of ultimate strength in shearing parallel to grain
