Many organizations perform component and equipment testing to ensure that parts in various applications and environments are robust and will operate reliably in the field. In addition, failure analyses are often performed to identify the cause of failures resulting from device testing and/or field usage. The Reliability Analysis Center (RAC) Data Sharing Consortium (DSC) accumulates data from these sources and assembles this data into a repository accessible to its members. This article discusses the purpose of the DSC, the benefits of DSC, and the data sharing agreement. It presents a list of organizations who are members of the DSC consortium and of organizations which are in the process of reviewing membership requirements. RAC's mission, the awards it has received, and its efforts towards developing and maintaining effective DoD systems are also covered.

This article details the results of a failure analysis performed on a Qualification Unit injector for a military satellite thrusters and explains that the failure was initially detected due to a shift in performance during qualification testing. Failure analysis involved non-destructive evaluation on the injector using micro-focus X-ray and scanning electron microscopy. Serial cross-sectional metallography was then performed, with each cross-section documented by optical microscopy and SEM. The failure analysis resulted in three main conclusions: (1) the root cause of the failure was attributed to multiple detonations in or around the damaged orifice; these detonations were likely caused by fuel and/or combustion products condensing in the orifice between pulses and then igniting during a subsequent pulse; (2) multiple damage mechanisms were identified in addition to the ZOT detonations; and (3) the material and platelet manufacturing process met all design parameters.

The purpose of this research is to examine the performance of tungsten heavy alloy (WHA) susceptible to adiabatic shear failures and to identify the microscopic findings of shear band and its effect on the engineering behavior. Experimental results show that the binder-phase (Fe-Ni) and tungsten particles (W) have the high work-hardening rate at low-strain-rate compression (10 -3 /sec). Thermal softening behavior is dominant at high-strain-rate (>10 3 /sec), and this material is relatively insensitive to strain rate in the range of 3000-5000/sec. The microscopic analysis by SEM reveals that most fractures in the shear band are intergranular where the Fe-Ni matrix has the least resistance to fracture. Transgranular fracture is also observed, but not significantly. With the constant strain rate, no shear band was observed under 30% compressive strain, whereas the extensive shear band was formed at the 50% strain with significant crack formation along the shear band zone and extends through the specimen thickness forming a cone shape inclined at an angle 40° to 50° to the loading direction. The measured surface temperature of the 40%-strained specimen is approximately 250 °C using high speed infrared temperature technique. A significant decrease in the ultrasonic velocities is measured with extension of the shear band.

The Aviation and Missile Command requested the US Army Research Laboratory to perform a metallurgical examination of a main rotor sub-assembly from an attack helicopter as vibration was noticed during a test flight after replacement of the main rotor head. This article presents the details of the metallurgical examination, the mechanical properties of and chemical analysis on the failed component, and the techniques adopted for the examination such as scanning electron microscopy, X-ray mapping, energy dispersive spectroscopy, and residual stress analysis. The discussion includes the details of crack origin, fatigue progression, and the circumstances which caused the point contact between a MP35N pin and a PH 13-8 Mo component. The failure of the main rotor strap pack outboard pitch cone bolt was attributable to galling. Several of the cracks may have propagated by fatigue and converged beneath the bolt inner diameter or adhesive wear may have induced a sub-surface crack origin.

This article deals with an investigation to determine the root cause of the differences noted in the fatigue test data of main rotor spindle assembly retaining rods fabricated from three different materials. The US Army Research Laboratory - Materials Directorate (ARL) subjected the failed tie rods to visual examination and light optical microscopy and then performed dimensional verification and measured the respective surface roughness of the rods in an effort to identify any discrepancies. Next, mechanical testing (hardness, fatigue, and tensile) was performed, followed by metallography, and chemical analysis. Finally, the ARL performed laboratory heat treatments at the required aging temperature. The results suggested that the difference in performance could not be directly linked to chemical composition, dimensional intolerance, surface roughness or any metallographic variance and that the likely explanation for the difference observed in the mechanical performance of materials lies within a variation of the heat treatment.