Test Speed
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Test speed
General information
The term test speed is preferably used in materials and plastics testing, regardless of the type of load and the duration of the load, but is also used to describe the speed of any type of deformation process, e.g. to analyse the flow speed [1−3].
Definition of terms
In plastics testing, the term test speed refers to the velocity applied to the test specimen by a loading device. When using an electromechanical or servo-hydraulic universal testing machine, with which tensile, compression, bending or shear tests can be carried out, for example, the test speed corresponds to the so-called crosshead speed (sometimes also pull-off speed) at which the movable crosshead moves up or down with the test specimen clamping. As the velocity must be independent of the resulting reaction force of the test specimen, it is kept constant with the so-called primary control loop of the testing machine. The term test speed is used explicitly in the plastics testing standards [4–11], although the crosshead speed vT is specified in a table, whereas the crosshead speed is used directly in the standard ISO 11339 [12], for example. Depending on the test arrangement or load type, a specific strain rate for the test specimen can then be calculated from the crosshead speed.
Terms of impact loading
For impact or drop-type test methods, the term test speed is only used in ISO 7765-2 [13], while in the other test standards the impact velocity is used [14–18]. In all cases, the term refers to the velocity v0 of the loading device (drop hammer or pendulum hammer) shortly before impact on the test specimen (unnotched, notched test specimen or round or rectangular test plate).
Strain state in the specimen
In all types of tests, it is generally assumed that the applied velocity causes a strain rate distribution and strain state of some kind in the test specimen and generates a force or stress as a reaction, which is displayed as a diagram and is used to calculate material values.
The following terms are also explained in more detail in the WIKI-dictionary of „Polymer Testing & Diagnostics“:
- Wiki-Dictonary: "Polymer Testing & Diagnostics" (https://wiki.polymerservice-merseburg.de)
- Velocity
- Notch geometry
- Crosshead speed
References
| [1] | Späth, W.: Physik der mechanischen Werkstoffprüfung. Springer, Berlin (2013), ISBN 978-3-642-99022-9 |
| [2] | Krüger, G.: Klettverschlüsse: Materialien, Herstellung, Prüfung, Anwendungen. Carl Hanser, München (2013), ISBN 978-3-446-43493-6 |
| [3] | Richter, H. W.: Instandhaltung von Rohrleitungen. Band 1: Sanierung und grabenlose Erneuerung von Druckrohrleitungen. Vulkan, Essen (2004), ISBN 978-3-8027-2730-6 |
| [4] | ISO 527-1 (2019-07): Plastics – Determination of Tensile Properties – Part 1: General Principles |
| [5] | ISO/DIS 527-2 (2024-09): Plastics – Determination of Tensile Properties – Part 2: Test Conditions for Moulding and Extrusion (Draft) |
| [6] | ISO 604 (2002-03): Plastics – Determination of Compressive Properties |
| [7] | ISO 178 (2019-04): Plastics – Determination of Flexural Properties |
| [8] | ISO 14125 (1998-03): Fibre-reinforced Plastic Composites – Determination of Flexural Properties; Technical Corrigendum Cor. 1:2001-07 + AMD 1:2011-05 |
| [9] | ISO 14126 (2023-10): Fibre-reinforced Plastic Composites – Determination of Compressive Properties in the In-plane Direction |
| [10] | ISO 14129 (1997-12): Fibre-reinforced Plastic Composites – Determination of the In-plane Shear Stress/Shear Strain Response, Including the In-plane Shear Modulus and Strength, by the + 45° Tension Test Method |
| [11] | ISO 14130 (1997-12): Fibre-reinforced Plastic Composites – Determination of Apparent Interlaminar Shear Strength by Short-beam Method; Technical Corrigendum 1:2003-11 |
| [12] | ISO 11339 (2022-05): Adhesives – T-peel Test for Flexible-to-Flexible Bonded Assemblies |
| [13] | ISO 7765-2 (2025-05): Plastics Film and Sheeting – Determination of Impact Resistance by the Free-falling Dart Method – Part 2: Instrumented Puncture Test |
| [14] | ISO/DIS 179-1 (2025-05): Plastics – Determination of Charpy Impact Properties – Part 1: Non-instrumented Impact Test (Draft) |
| [15] | ISO 179-2:2020-05: Plastics – Determination of Charpy Impact Properties – Part 2: Instrumented Impact Test |
| [16] | ISO 180 (2023-06): Plastics – Determination of Izod Impact Strength |
| [17] | ISO 6603-1 (2000-03): Plastics – Determination of Puncture Impact Behaviour of Rigid Plastics – Part 1: Non-instrumented Impact Testing |
| [18] | ISO 6603-2 (2023-06): Plastics – Determination of Puncture Impact Behaviour of Rigid Plastics – Part 2: Instrumented Impact Testing |