Solid Particle Erosion Testing of Helicopter Rotor Blade Materials

Abstract

The Army Research Laboratory (ARL) was asked to participate in an OSD-funded erosion effort by the Coating Technology Integration Office at Wright Patterson Air Force Base. Solid particle (sand) erosion testing was conducted by the University of Dayton Research Institute to determine the erosion resistance of materials currently used on the leading edges of Army aviation rotor blades of aircraft in Southwest Asia (SWA). This testing and evaluation was important for two reasons; first, Iraq and Afghanistan are the primary locations of our current anti-terror operations, and second, the sands within these two countries are the worst in the world from an erosion standpoint (dry conditions ? freshest grains of sand ? predominantly angular quartz grains ? blowing winds). The sand utilized herein is considered even more erosive than the sand from these two countries, since they contain a higher concentration of quartz than the SWA sand. In 2005, observations of actual SWA field failures of helicopter rotor blade protective tapes and coatings were compared to existing state-of-the-art, laboratory-based sand erosion data during a U.S. Army sponsored program. Laboratory-produced data did not match the severity of field-use damage, even under extremely high levels of particle loading. The need to test to erosive failure representative of this environment was determined to be paramount in establishing relative performance levels of erosion resistant protective systems being screened for potential field use. The goal of this effort was to provide two synthetic sand formulas capable of testing various polymer-based candidate rotor blade protective systems to failure. The test media was derived from characterization of sand and dust materials unique to SWA. The synthetic sand mixtures developed by this effort will be incorporated in a new test protocol for sand erosion to represent a truly ''worst case'' test, with extended application to other aerospace components susceptible to sand erosion damage applicable to Department of Defense activities in most dry-hot desert regions. Comprehensive post-test analysis performed by ARL included: visual examination, mass loss calculations, erosion rate determination, surface roughness testing, volume loss calculations, scanning electron microscopy characterization, and metallography. As a result of post-test analysis, many trends were observed, with the results documented herein. The results of this testing have been used as a baseline for future testing of alternative materials and coating systems, and to prepare a solid particle erosion test standard (MIL-STD-3033).

Dynamics of supersonic microparticle impact on elastomers revealed by real–time multi–frame imaging

“…Elastomeric polymers are promising materials for ballistic impact protection both on the macroscale (for example, in armour panels 7 ) and on the microscale, for example as protective coatings for helicopter rotor blades 8 and in powder blasting 3 . Among elastomer candidates for enhanced ballistic protection, polyureas, polyurethanes, and PUUs have recently gained interest owing to their versatile dynamic response 9 10 11 12 .…”

“…Experimental investigations of microparticle impact on elastomers are typically conducted by studying erosion resulting from a prolonged exposure to multi–particle impact (see, for example, refs 3 , 8 , 17 , 18 , 19 ). Rebound resilience 20 21 , incremental growth of cracks under cyclic loading 22 , viscoelastic effects 21 23 , and heat build–up 24 were noted among other plausible attributes of relevance to solid particle erosion wear observed over a broad range of rubbery materials.…”

Study of Solid Particle Erosion on Helicopter Rotor Blades Surfaces

“…SPE depends on the particle velocity and impact angle, in addition to many other factors [1]. Due to the specialized nature of the work environment, where helicopters and transport aircrafts often take off and land in a desert or on the battlefield, dust erosion is frequently a problem [2]. Erosion caused by high-speed solids can result in component loss, especially in the main rotor blades of helicopters and the turbine blades of aircrafts [3].…”

Key Problems Affecting the Anti-Erosion Coating Performance of Aero-Engine Compressor: A Review

“…Sand erosion is a common phenomenon in the industrial field [1][2][3], especially in area with both wind and sand such as power and energy equipment, resulting erosion on inner wall of the pipeline and so on. However, the erosion issue in the field of aviation is quite different and more severe than the above [4][5][6][7], such as helicopters and transports taking off and landing in desert areas, as sand particles are sucked into the engine at high speed, as shown in Figure 1. High concentration of sand leads to serious damage to high speed rotating compressor located at the front of the engine [8], which may further lead to downgrade of engine performance, decrease in reliability and even shorter the service life.…”