ISO 26203-2-2011 pdf download.Metallic materials – 1 Tensile testing at high strain rates – Part 2: Servo-hydraulic and other test systems.
This part of ISO 26203 gives requirements for the testing of metallic materials. Only examples for testing flat geometries are given; however, other geometries can be tested. The area of application spans a range of strain rates from 1O2 s-1 to i03 s1. Tests are carried out between 10 °C and 35 °C and, unless otherwise specified, using a servo-hydraulic-type test system.
NOTE 1 Measurements at strain rates lower than 10-2 s can be performed using machines designed for quasi- static testing.
NOTE 2 For test piece geometries other than those shown in 7.1 and Annex B, see ESIS P7 (Reference [1]) and FAT Guideline (Reference [2]).
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 6892-1 apply.
4 Symbols
For the purposes of this document, the symbols given in ISO 6892-1 apply. Additional symbols, units and descriptions are provided in Table 1.
5 Principle
The stress-strain characteristics of metallic materials at specific plastic strain rates are determined.
To perform tension tests at strain rates above those described in ISO 6892-1, the measurement of force and elongation of the original gauge length, L0, shall meet additional requirements in order to obtain reliable high-rate stress-strain curves. This part of ISO 26203 describes the requirements for determining and evaluating the stress and strain in force equilibrium during plastic deformation at strain rates up to i03 s1.
6 Apparatus
Testing machines in conformity with this part of ISO 26203 work on the principle that the kinetic energy required for the test is applied on the impact (or loading) side of the test piece (see Figure A.1). The load cell is located at the opposite end of the test piece, which is fixed or restrained in a clamp/grip (see Figure A.1). Loading at high strain rates is preferably impact-like and, therefore, often does not allow a fixed coupling of the test piece to the testing machine. All testing machines that permit a constant strain rate (within certain bounds: see 9.3) during the entire test are suitable for testing.
The most common high-rate testing machine applicable to this part of ISO 26203 utilizes a servo-hydraulic drive fitted with a slack adapter (see Reference [3]). Other systems, which may include, for example, flywheel impactors and drop towers, may be used on condition that the requirements given in this part of ISO 26203 are met.
An axial-symmetric parallel alignment of the test pieces in the load train shall be verified in order to prevent bending moments. The alignment of the load train elements may be performed in accordance with ASTM E1012 (see Reference [4]).
From a mechanical point of view, the load train should be compact and easy to manage. This enables the load train to attain short acceleration times while also maintaining the natural frequency of the clamping and load cell system at as high a level as possible.ISO 26203-2 pdf download.