Polymer Casing Stress Tolerances under High Velocity Thermal Expansion Tests
High velocity thermal expansion tests require real-time internal strain mapping because surface growth measurement misses internal wall cracking.
Optical Extensometry
Meaning
Measurement of the elongation or strain in a material uses digital cameras to track the distance between two marked points on a sample. This optical extensometry allows for testing without any physical contact between the sensor and the specimen, which is necessary for very thin or fragile materials. It provides a highly accurate way to determine the mechanical properties of new packaging films or gaskets.
Deformation Scale
Tracking the movement of the material under load reveals the yield point and the ultimate tensile strength. When optical extensometry is used, the system can measure strain across the entire surface of the sample. This provides a more detailed picture than a traditional clip-on extensometer that only measures a single point.
Hardware Alignment
Accuracy depends on the precise positioning of the cameras and the quality of the markers on the material. Using optical extensometry requires a stable testing environment with controlled lighting and no vibration. This ensures that the results are repeatable and can be used to compare different material formulations.
The software analyzes the video feed in real time to provide immediate feedback on the progress of the test. Its ability to handle large deformations makes it ideal for testing rubber and plastic components.
Testing Constraint
Clear access to the sample is required throughout the duration of the test. Using this technology as part of the material selection process reduces the risk of package failure during high stress events like a drop or a stack. Reliable material data is the primary driver of successful product development.