Structural Health Monitoring of M1114 High Mobility Multipurpose Wheeled Vehicle Armor System

The M1114 High Mobility Multipurpose Wheeled Vehicle (HMMWV) has been the workhorse vehicle of the U.S. Armed Forces in Afghanistan and Iraq. Donald Rumsfeld, Secretary of Defense, was faced with massive public criticism in 2004 for not equipping our military personnel in Afghanistan and Iraq with M1114s that had the proper ballistic armor. In May 2004, a $618M Senate Bill was passed to increase the production level of HMMWVs and improve their ballistic protection capabilities while minimizing additional weight. While the military is taking advantage of using composite armor on the HMMWV, it does not have a rigorous method to detect, locate, and quantify damage on a two-layer composite armor system. Structural Health Monitoring (SHM) is the process of implementing a damage detection and characterization strategy for engineering structures. Damage is defined as changes to the material and geometric properties of a structural system, including changes to boundary conditions and system connectivity, which adversely affect the system\u27s performance. An active SHM system was developed to detect, locate, and quantify damage on a two-layer composite armor (HJ1 composite with ceramic frontal plates) that encounters impact from a 0.30 caliber armor piercing projectile. An adaptive version of a one-at-a-time experiment was used during this research. Base line testing was performed to provide information on the structural properties and wave propagation characteristics of the material. Ballistic testing was completed to replicate David Fecko\u27s experiment of maximum V50 velocity of 947 meters per second and a ceramic-to-composite ratio of 60/40

Flaw investigation in a multi-layered, multi-material composite: Using air-coupled ultrasonic resonance imaging

Ceramic tiles are the main ingredient of a multi-material, multi-layered composite being considered for the modernization of tank armors. The high stiffness, low attenuation, and precise dimensions of these uniform tiles make them remarkable resonators when driven to vibrate. Defects in the tile, during manufacture or after usage, are expected to change the resonance frequencies and resonance images of the tile. The comparison of the resonance frequencies and resonance images of a pristine tile/lay-up to a defective tile/lay-up will thus be a quantitative damage metric. By examining the vibrational behavior of these tiles and the composite lay-up with Finite Element Modeling and analytical plate vibration equations, the development of a new Nondestructive Evaluation technique is possible. This study examines the development of the Air-Coupled Ultrasonic Resonance Imaging technique as applied to a hexagonal ceramic tile and a multi-material, multi-layered composite

Flaw detection in Multi-layer, Multi-material Composites by Resonance Imaging: utilizing Air-coupled Ultrasonics and Finite Element Modeling

Ceramic tiles are the main ingredient of a multi–material, multi–layered composite being considered for the modernization of tank armors. The high stiffness, low attenuation, and precise dimensions of these uniform tiles make them remarkable resonators when driven to vibrate. Defects in the tile, during manufacture or after usage, are expected to change the resonance frequencies and resonance images of the tile. The comparison of the resonance frequencies and resonance images of a pristine tile/lay–up to a defective tile/lay–up will thus be a quantitative damage metric. By examining the vibrational behavior of these tiles and the composite lay–up with Finite Element Modeling and analytical plate vibration equations, the development of a new Nondestructive Evaluation technique is possible. This study examines the development of the Air–Coupled Ultrasonic Resonance Imaging technique as applied to a hexagonal ceramic tile and a multi–material, multi–layered composite

Development Of A Procedure For The Detection Of Subsurface Defects In Bridge Deck Joint Armor Using Ground Penetrating Radar And Seismic Properties Analysis

The overall performance and longevity of highway bridges is highly dependent upon the integrity of their deck joints. The North Carolina Department of Transportation has experienced problems with bonding in the armored deck joints installed on many of its bridges. These defects have historically been detected using conventional NDT techniques such as visual inspection, chain-dragging and by detecting sounds made by the joint due to passing traffic. By the time these methods are effective the joint has usually failed, however, and must be replaced

Divertor of the European DEMO: Engineering and technologies for power exhaust

In a power plant scale fusion reactor, a huge amount of thermal power produced by the fusion reaction and external heating must be exhausted through the narrow area of the divertor targets. The targets must withstand the intense bombardment of the diverted particles where high heat fluxes are generated and erosion takes place on the surface. A considerable amount of volumetric nuclear heating power must also be exhausted. To cope with such an unprecedented power exhaust challenge, a highly efficient cooling capacity is required. Furthermore, the divertor must fulfill other critical functions such as nuclear shielding and channeling (and compression) of exhaust gas for pumping. Assuring the structural integrity of the neutron-irradiated (thus embrittled) components is a crucial prerequisite for a reliable operation over the lifetime. Safety, maintainability, availability, waste and costs are another points of consideration. In late 2020, the Pre-Conceptual Design activities to develop the divertor of the European demonstration fusion reactor were officially concluded. On this occasion, the baseline design and the key technology options were identified and verified by the project team (EUROfusion Work Package Divertor) based on seven years of R&D efforts and endorsed by Gate Review Panel. In this paper, an overview of the load specifications, brief descriptions of the design and the highlights of the technology R&D work are presented together with the further work still needed

Application of Artificial Intelligence for Surface Roughness Prediction of Additively Manufactured Components

Additive manufacturing has gained significant popularity from a manufacturing perspective due to its potential for improving production efficiency. However, ensuring consistent product quality within predetermined equipment, cost, and time constraints remains a persistent challenge. Surface roughness, a crucial quality parameter, presents difficulties in meeting the required standards, posing significant challenges in industries such as automotive, aerospace, medical devices, energy, optics, and electronics manufacturing, where surface quality directly impacts performance and functionality. As a result, researchers have given great attention to improving the quality of manufactured parts, particularly by predicting surface roughness using different parameters related to the manufactured parts. Artificial intelligence (AI) is one of the methods used by researchers to predict the surface quality of additively fabricated parts. Numerous research studies have developed models utilizing AI methods, including recent deep learning and machine learning approaches, which are effective in cost reduction and saving time, and are emerging as a promising technique. This paper presents the recent advancements in machine learning and AI deep learning techniques employed by researchers. Additionally, the paper discusses the limitations, challenges, and future directions for applying AI in surface roughness prediction for additively manufactured components. Through this review paper, it becomes evident that integrating AI methodologies holds great potential to improve the productivity and competitiveness of the additive manufacturing process. This integration minimizes the need for re-processing machined components and ensures compliance with technical specifications. By leveraging AI, the industry can enhance efficiency and overcome the challenges associated with achieving consistent product quality in additive manufacturing.publishedVersio

Laboratory Resistivity Measurements for Soil Characterization

Field based electrical resistivity measurements, such as electrical resistivity tomography (ERT) and capacitively coupled resistivity (CCR), are geophysical methods that offer a non-destructive and rapid means to collect continuous data. As such, ERT and CCR are becoming increasingly popular tools for geotechnical engineers; however, it is challenging to derive geotechnical information such as soil type, density, and water content from the data. A laboratory geophysical investigation was carried out to gain a better understanding of the parameters that affect the electrical resistivity of soils and devise a relationship between resistivity and soil type or classification. In this study, a soil box attached to a resistance meter in a 4-electrode Wenner array was used for the resistivity measurements. Nine different benchmark soils were tested, representing most of the major soil groups according to the unified soil classification system. The effects of water quality, water content, degree of saturation, bulk density, dry density, Atterberg limits and temperature on the measured electrical resistivity of the soils were investigated. Although there is an apparent correlation between all of these parameters and the electrical resistivity of soils, the parameters that are most effective in the identification of soil type are bulk density and degree of saturation. The laboratory results indicate that if the soil is saturated, a reasonable estimate of the soil group classification can likely be made from resistivity alone. For unsaturated samples, the range of possible resistivity values is much larger; however, the estimate of soil group can be significantly narrowed down if an approximation of saturation or density can be made. To assess the feasibility of the developed approach, a series of verification studies using samples acquired from the field and other processed soils were also conducted