North America

Green Room - Session 6

9:15 to 10:15 a.m. Thursday, June 15, 2017

HALT Fixturing – Theory and Practical Examples

An effective and productive HALT test requires that the Unit Under Test (UUT) experience sufficient shock and vibration excitation to expose mechanical weak links. This means that the fixturing that secures the UUT to the table must transmit the energy well into the UUT. Unfortunately, most engineers who have dealt with designing vibration fixtures have worked with Electro-Dynamic (ED) vibration systems. In HALT, Repetitive Shock (RS) systems are used. The nature of the stresses from RS systems are radically different than ED systems, resulting in fixture designs that are also radically different from those used in ED systems. Without an understanding of the reason for the differences and the best ways to approach RS fixture design, an engineer can unwittingly design a fixture that more complex and expensive than necessary, and that results in very poor mechanical stresses in HALT.

This presentation outlines the importance of good fixturing, the basic differences between ED and RS vibration, and why the fixturing approach must be different. The bulk of the presentation describes fixturing requirements for various UUT types and configurations, with multiple real-world examples that provide clear, practical and useful information for the engineer responsible for designing HALT fixtures.

Key Words: HALT, HASS, Repetitive Shock, Electro Dynamic, Fixturing, Thermal, Vibration, Isolation, Transmission

Neill Doertenbach

Qualmark Corporation

Denver, Colorado