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Random Vibration: Probabilistic Forces
Published in Haym Benaroya, Mark Nagurka, Seon Han, Mechanical Vibration, 2017
Haym Benaroya, Mark Nagurka, Seon Han
The goal of HALT is to proactively and quickly find design weaknesses, affording engineers the opportunity to fix them prior to product launch. Because of its accelerated nature, HALT is typically faster and less expensive than traditional testing techniques. During product development, it can expose reliability issues at a time when changes are much less costly to make. By finding weaknesses and making changes early, HALT can lower product development costs and compress time to market. HALT can also be used when a product is being introduced into the market to expose potential problems caused by new manufacturing processes as well as after a product has been introduced into the market to test product reliability caused by changes in components, manufacturing processes, suppliers, etc. HALT is used by most manufacturers in a wide range of industries to improve reliability of products.
Age Acceleration
Published in Joel A. Nachlas, Reliability Engineering, 2017
In recent years, the use of HALT and HASS has increased considerably. HALT is “highly accelerated life testing” and HASS is “highly accelerated stress screening.” Both have strong advocates. In both cases, the idea is to impose very severe environmental stresses upon a device even if those stress levels exceed the conditions the device is designed to tolerate. The motivation for these two practices is to obtain very high levels of acceleration for devices that nominally have very long lives. The fact that additional failure modes that are not typical of device behavior occur is accepted under the assumption that those overstress failures will be recognized as such and conclusions about the device behavior in service will be adjusted appropriately. The use of these methods is still quite controversial, and the soundness of their use needs to be examined individually for each device to which their application is proposed.
Testing
Published in Paul H. King, Richard C. Fries, Arthur T. Johnson, Design of Biomedical Devices and Systems, 2018
Paul H. King, Richard C. Fries, Arthur T. Johnson
A second function of HALT testing is that it characterizes the equipment under test, and identifies the equipment’s safe operating limits and design margins. Data from a HALT test are therefore used as a basis for the design of an optimal HASS or ESS test, which is used to screen every piece of production equipment for latent manufacturing defects and defective components. HASS or “highly accelerated stress screening” is an extension of HALT but is applied during production.
Numerical and experimental investigation on multiaxial fatigue damage estimation of Qualmark chamber test table structures under random vibrations
Published in Mechanics Based Design of Structures and Machines, 2023
The Qualmark Chamber aims to test the reliability of a product by breaking it to detect defects during the manufacturing process using the HALT (Highly Accelerated Life Test) and HASS (Accelerated Method) methods accelerated stress).