Evolution of USAF Damage Tolerance design philosophy

In the early days of aviation, the concept of fatigue life was not a prime consideration in design. Aircraft did not typically have a long service life and were designed based on ultimate strength. Early aircraft failures occurred due to component/system failures, combat damage, and pilot error. Aircraft did not typically last long enough for fatigue to become an issue. As the design of aircraft became more sophisticated and pilot skill increased, aircraft began to last longer and fatigue became a critical concern. Continue reading Evolution of USAF Damage Tolerance design philosophy

Happy birthday to the contour method

Today marks a major milestone in the field of residual stress measurement. The contour method, one of the most useful and advanced residual stress measurement techniques, was first successfully implemented on this date (August 16th) in 1999 by Mike Prime at Los Alamos National Laboratory. The most significant feature of the contour method is its ability to generate detailed two-dimensional residual stress maps like the one shown below. Please join us in wishing the contour method a very happy 18th birthday! Continue reading Happy birthday to the contour method

Tensile test

A tensile test is a standard method used by material scientists and engineers to determine important material strength and ductility properties. For example, tensile tests can be used to measure the yield strength of a material, which is defined as the stress at which a material begins to deform plastically. Hill Engineering has ample experience performing tensile tests, and other mechanical property tests, in pursuit of our passion to maximize the potential of materials. Continue reading Tensile test