Loading-strain equivalence between thermomechanical, creep, and tensile tests: High density polyethylene
Abstract
The initiation of any mechanical test, performed on a specimen of any material, requires first that the specimen be loaded. Any loading of a specimen causing it to deform may affect the test it initiates. The creep test (CT) is a dead-load test while the engineering tensile test (TT) is a pure loading test (load versus strain at constant crosshead-speed from its initiation to the yield point). In the CT, the specimen requires dead-load loading (DLL) at some DLL initial-crosshead-speed (HS) after which it creep-strains with time under a constant dead-load. In the literature, however, there is a neglect for loading (for example, neglecting to specify loading rates) in the CT. The assumption, in many cases, is that loading plays a minor role in creep-strain initiation so that loading effects can be precinded from regarding the remainder of the CT. This paper attempts to show that the loading parameters are very important for the initiation of the CT in plastics and that the loading mode has a bearing not only on the CT but also on the thermomechanical test (TMT).
- Publication:
-
Final Report Army Research Lab
- Pub Date:
- July 1994
- Bibcode:
- 1994arl..reptS....W
- Keywords:
-
- Creep Tests;
- Loading Rate;
- Polyethylenes;
- Structural Strain;
- Tensile Tests;
- Thermomechanical Treatment;
- Time Constant;
- Yield Point;
- Elastic Deformation;
- Load Tests;
- Stress-Strain Relationships;
- Tensile Strength;
- Thermal Expansion;
- Structural Mechanics