ISO 16808 is an ISO test method for determining a biaxial (true) stress–strain curve for metallic sheet and strip using a bulge test with optical measuring systems.
It is commonly used when uniaxial tensile data is not enough for forming and stretch-forming conditions, or when higher strain levels are needed for modeling and validation. If you need help matching the cited edition to your bulge-test setup, talk with our team.
ISO 16808: Metallic materials — Sheet and strip — Determination of biaxial stress-strain curve by means of bulge test with optical measuring systems
ISO 16808 specifies a bulge-testing approach for generating a biaxial stress–strain curve from metallic sheet material under stretch forming conditions, using optical measurements to capture deformation.
The method is intended for metallic sheets with thickness below 3 mm and is designed to minimize friction influence so the measured response better reflects material behavior in stretch forming.
Quick Definition
Document type: Test method (bulge test with optical measurement) for developing a biaxial (true) stress–true strain curve for metallic sheet/strip.
Primary output: Biaxial stress–strain curve derived from bulge deformation data and measured pressure/loading.
Common use case: Material characterization for stretch-forming conditions where higher strain levels are needed than typical tensile testing can provide.
What This Standard Covers
ISO 16808 covers a procedure for bulge testing of metallic sheet/strip in a pure stretch-forming condition while using an optical measuring system to track deformation.
Because the deformation field is measured optically, the test is commonly aligned with modern full-field strain measurement practices used in forming labs and R&D environments.
Why This Standard Matters in Testing
When sheet metal is formed in production, the material often experiences biaxial stretching rather than simple uniaxial tension. A bulge-based stress–strain curve can better reflect this condition and can be used to support forming-process development, simulation inputs, and comparative material studies.
ISO 16808 also highlights that higher strain values can be achieved versus tensile testing, which is often important when evaluating materials intended for demanding stretch-form operations.
Common Materials, Product Types, or Applications Covered
ISO 16808 applies to metallic sheet and strip. Typical application areas include:
- Sheet metal forming R&D (stretch forming and related processes)
- Automotive, transportation, and general manufacturing sheet materials
- Material model development and validation where biaxial response is important
Practical applicability depends on thickness limits, specimen geometry/blank size supported by your bulge fixture, and the optical system’s ability to resolve strain over the required range.
Common Test or Verification Workflow
ISO 16808 testing is commonly implemented as a controlled bulge test with synchronized optical measurement and pressure (or other applied loading) measurement.
Common workflow: Prepare sheet specimen and optical surface patterning as needed, clamp the sheet in the bulge fixture, apply controlled bulging while recording pressure and optical deformation data, then reduce the measurements to a biaxial (true) stress–strain curve for reporting and engineering use.
Revision sensitivity: Curve calculation approach, required measured channels, and reporting expectations can vary by edition and should be matched to the exact ISO 16808 version cited on drawings, customer requirements, or internal specifications.
Equipment Commonly Used for This Standard
ISO 16808 points to a bulge test system equipped for controlled deformation and optical strain measurement. The standard is equipment-oriented in the sense that the optical system and pressure/loading measurement quality directly affect the final curve.
Common equipment: Bulge test fixture (for sheet/strip), pressure or load application and control hardware, pressure transducers and data acquisition, optical measuring system (often full-field), lighting and imaging accessories, and analysis software for converting measurements into a biaxial stress–strain curve.
If you are comparing fixture sizes, pressure ranges, or optical measurement packages for ISO 16808 work, you can request a detailed quote for a configuration matched to your sheet thickness range and strain measurement needs.
How to Read This Designation or Revision
Current edition: ISO 16808:2022 (Edition 2).
Previous edition: ISO 16808:2014 is listed as withdrawn and may still appear in legacy internal documents, older customer specifications, or historical test reports.
When a requirement calls out “ISO 16808” without a year, it is good practice to confirm which edition is expected before finalizing test planning, acceptance criteria, or data format.
Related Standards, Methods, or Frameworks
ISO 16808 is often used alongside broader sheet metal characterization programs that may include uniaxial tensile testing and forming-related measurements. When requirements reference multiple methods, the key is ensuring the combined dataset is consistent in units, strain definitions (engineering vs true), and reporting format.
For multi-method qualification programs, align the cited standards list and the expected material model outputs before testing begins.
Get help selecting an ISO 16808-ready bulge and optical measurement setup
If you are building or upgrading a bulge-test workflow for ISO 16808 and need to align fixture capacity, measurement channels, and optical strain measurement performance, request pricing for an equipment package tailored to your lab’s sheet-metal testing scope.