Multi-Specimen Fatigue

Durability testing can take a long time, especially when the material or product is expected to last for many years and a high number of cycles. Multi-specimen fatigue shortens durability test time by simultaneously applying cyclic displacement to many samples and detecting each sample’s cycles-to-failure for the applied loading level. This allows users to generate many failure datapoints for each loading level. When multiple tests are run on similar samples, researchers can quickly build SN curves (S-n Curves) with many data points to improve statistical confidence levels of the resulting fatigue model. Otherwise, these millions, 10s of millions and even 100s of million cycle-long tests can extend product development time and hinder efforts to accelerate time to market of new materials and products.

Multi-specimen fatigue instruments use a dynamic linear motor and have the capacity to secure many samples into a test fixture and effectively share the loading from that motor. This approach applies a common displacement amplitude to all samples, often using a high frequency sinusoidal loading profile to accelerate the fatigue loading on the many samples. Each specimen has a force sensor to track the applied force; this sensor measures the degradation and/or failure point (number of cycles to failure) for that sample.