DVI's President has over 18 years of experience working with the Department of Defense, and has worked with the Air Force, Army, Navy, Marines, and Special Operations Command (SOCOM). Below are case studies that DVI's Aviation Experts have been a part of.
Survey of Weapon System Degradation in Desert Environments
DVI’s President was a co-principle investigator in a major survey to document and analyze the wear and deterioration of military equipment returning from operations in Iraq and Afghanistan. The two major contributing factors to the deterioration of equipment were the abrasive and corrosive effects of sand and the high operational usage rate. The desert sand is like a very fine talcum powder and can intrude into all of the smallest crevices. Abrasive wear caused by sand particulates is bad enough by itself, but it was also found to be mixed with oil to form an abrasive paste that greatly increased wear on the mechanical parts. It is also common to find lubrication fittings containing contamination that can easily enter and contaminate the lubrication system. This coupled with the concentration of reactive chemicals, primarily salts and carbonates, in the sand is the driving mechanism for accelerated wear.
Failure of Coatings in the Desert
Weapons systems have to be designed to withstand the harsh desert environments of Iraq and Afghanistan. Often times, weapon systems have to be transported without protective enclosures over extended periods while on convoys and recon patrols. This results in a severe degradation of the external coatings that provide corrosion protection and camouflage. Unfortunately, when these coating were developed and certified, the unprotected handling of the systems on convoys or recon was never anticipated. As a result these external coatings are failing after a short period of time, leaving the bare substrate material exposed to corrosive elements and leaving a shiny reflective surface that can be spotted by enemy forces. DVI’s President evaluated these problems, tested alternate coatings, and has made recommendations to mitigate this problem.
Failure Analysis of Weapons that use Wet Lubricants
DVI’s President was a co-principle investigator in a major program to independently test, analyze and rank the performance of emerging coating technologies by use of modified ASTM bench scale testing techniques. This entailed developing an analytical method to properly match and select specific bench-scale tests to the actions of actual weapon components. The modified ASTM tests were uniquely designed for each weapon platform to accurately simulate the loads, speeds, and action movement of the full scale counterparts. As a result of this program, hundreds of coatings were tested and ranked based upon their measured coefficient of friction, abrasive wear rate, adhesive wear rate, and corrosion resistance.
Failure of Top Side Structures Naval Structures due to High Speed Wave Stuffing
Certain Navy craft are capable of traveling over 60KTS, and waves “stuff” over the bow and can cause catastrophic failures of the pilothouse, resulting in injuries to the crew. DVI’s President modeled, tested, and empirically determined the peak stuffing loads and mode of actual structural failure. A new pilothouse was designed using advanced composite materials, capable of withstanding very high speed water impacts. The new composite pilothouse also included bullet proof windows, radar absorbing technology, and embedded antenna arrays.
Preventing Fuel Pump Failures
With the major combat operations in Afghanistan and Iraq, fuel-related problems have increased significantly. In both Afghanistan and Iraq, the ground vehicles and equipment are being used much more extensively than they would be used in normal service. Considering this added use, the hot temperatures that typically prevail in the Middle East, and the increasing engine-power demands imposed by the increased weights of up-armor kits, it is no wonder that the ground vehicles and equipment that have rotary-distribution, fuel-injection pumps have had many fuel-related engine problems. In these pumps, the fuel provides the needed lubrication to the internal moving components. When the lubricity (lubricating quality) of the fuel becomes marginal or insufficient, the pump components will wear. American Society for Testing and Materials (ASTM) D 975, Standard Specification for Diesel Fuel Oils, sets the current industry standard for the minimum viscosity of grades 1–D and low sulfur 1–D diesel fuel. DVI’s President contributed to developing a portable fuel lubricity tester that could be used to test local fuel sources, in theatres of operations, for adequate lubricity.
Methods for Improving Wear Testing
DVI’s President contributed to an effort to develop a better method for measuring the abrasive wear of very hard and very thin coatings. Although the ASTM G65 method is the most widely used method for assessing dry, three body abrasion; it is limited in which abrasives can be used by the need to achieve uniform flow of the abrasive through the feed nozzle of the hopper. For example, fine dust and talc-like powders do not flow well and are difficult to use in the ASTM G65 method. Less used abrasion test methods involve introducing abrasive particles into pin-on-disk and pin-on-drum tests, but these tests are usually limited to two-body abrasion or to abrasive slurries because the geometry and motion of these tests tends to move loose, dry abrasive particles out of the contact track. Another abrasion test, which is often referred to as a ball crater micro-abrasion test, involves using abrasive with a steel ball or wheel to make small craters in a test specimen. Unfortunately, none of these test methods provides the ability to measure dry, three-body abrasion with the full variety of abrasives that are encountered in actual use. . A new test machine, based on a Ball-On-Three-Disk (BOTD), allows abrasion tests to be conducted with and without lubrication, and it allows use of slurries, elevated temperatures, controlled environmental conditions, and oscillatory and unidirectional motion. DVI's President, Steve Meyers, has also co-authored numerous papers on this project work. Evaluation of the Wear and Abrasion Resistance of Hard Coatings by BOTD Test Methods, Quantifying Abrasive and Adhesive Wear of Coatings with a Ball on Three Disk Configuration, Improved Ball Crater Micro-abrasion Test
Improving the Takeoff Performance on Snow Runways
The LC-130 can experience significant take off problems in some snow conditions, because of the frictional drag created by the skis. Take-off difficulties often require multiple takeoff attempts, often numbering a half dozen or more, reducing cargo, or delaying take-off for hours until the temperature changes. DVI's President worked to identify a low-friction, impact-resistant, abrasion-resistant, and hydrophobic coating for applications on the LC-130 fleet. Selecting potential improvements to the skis of the LC-130 requires understanding why friction in the ski-snow interaction changes as the snow morphology changes with varying temperature, and why these changes are more pronounced in new snow then in old snow, or in prepared snow.
