 Control drop simulates physical interactions on the product, while environmental chamber simulates the stress profile of thermal cycling, elevated temperature, or combined environmental stresses to induce fatigue damage.The profile should stimulate the precipitation of latent defects that may be introduced from the manufacturing process but not remove significant life from the product or introduce flaws to risk failure during its intended mission.highly accelerated stress test is a Ongoing Reliability Test that uses the empirical operational limits as the reference for the combined vibration, thermal cycling, and other stress applied to find latent defects.