The Benefits of Small Specimen Fatigue Testing: How To Prevent Structural Failures?

fatigue testing instruments

There are three phases of fatigue testing each is driven by changing test conditions and can have different levels of effect on the specimen. In the biological industry, different specimens are commonly used for biological stress analysis, stress analysis, and physiological stress analysis. These include epithelial cells, polymers, cell debris, tissue hydrogels, etc. The topic of bio-testing is broad because biological samples can be of any type: cultured or semi-cultured, cells or tissues, etc. When one is starting to tackle fatigue testing for biological samples, it is important to understand which specimen properties are relevant.

Why Small Specimen Fatigue Testing?

Virtually all testing procedures require a specimen with some form of force at some point in time to achieve a defined effect. As mass engineering moves to smaller diameters, the need for testing small specimens has become very apparent.

The change in sample volume, pressure drop, and the need to test under different conditions make it very challenging to find standardized techniques and training. Hence, it is crucial that a consistent workflow with best practices be developed that produces reliable results.

Standardization of procedures is essential for bringing consistency to the sector. Unfortunately, the existing practices vary greatly and are both expensive and time-consuming.

Why Is Small Specimen Fatigue Testing Useful For Different Industries?

Each material undergoes different mechanical stresses as it passes through each failure location during the test. Research on each of the failure locations will provide data that can be used to understand the effects of aging and their resistance to chemical attacks. This may yield structural failures due to fatigue that may not have otherwise been detected or may not even be possible to discover.

For example, when designing injection molded parts for medical devices, ultrasonic imaging and compression testing can identify structures that fail under static loads but are not visible using standard images.

Engineers need to understand the effects of fatigue on materials used in any industry that uses an injection molding machine for injection molding parts.

How Can You Prevent Structural Failures From Occurring With These Small Specimens?

Well, for the specimen having fewer than 30 dimensions or 21mm in diameter, it is usually advisable to use a wide bore test die. However, in some cases, such as when thinning or depositing metal, it is necessary to use a narrow bore test die.

For thinning a small specimen, the clamping force, clamping force, and depth of the pincer drop can be optimized using the corresponding test dies.

To measure material fatigue at different angles, the cone of the test die can be adjusted to best suit the specimen’s angles. The laboratory scientist can often run a wide range of sample angles with a test die and even at different angles for a single test series.

Conclusion

There are three key factors to consider when doing small-scalar material testing: material thickness, specimen size, and loading. Small specimens such as the ones ADMET’s analyzers can handle in their analyzers can be difficult and expensive to handle and, therefore, time-consuming to implement. To be successful with test results, structural characterization of the test material must be performed. Specimen fatigue testing can benefit both basic science research and industry.

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