Browse Topic: Wear
Radiation has garnered the most attention in the research that has been conducted on polyethylene sheets. According to the calculations, there were 145892.35 kGy in total radiation doses administered. An ultraviolet visible spectrophotometer was used to examine the impact that electron beam irradiation had on the optical constants. Two of the most crucial variables taken into account when calculating the optical constants and the absorption coefficient are the reflectance and transmittance of polyurethane sheets. Reduced light transmission through the sheet achieves these characteristics, which are related to the transmittance and reflectance of the Fresnel interface. Cross linking makes it more challenging for the polyurethane molecular chains to become fixed. Both the refractive index and the dispersion properties have been altered as a direct result of this. Despite the fact that the doses of electron irradiation were getting lower, it eventually rose to 105 kGy. Contrary to the
Clutch wear is a significant factor affecting vehicle performance and maintenance costs, and understanding its dynamics is crucial for original equipment manufacturers (OEMs) to enhance product reliability and customer satisfaction. It is important to predict clutch wear to enable customers to understand the condition of their clutch and the remaining clutch life, to avoid sudden vehicle breakdowns. This paper explains the approach of measuring the clutch wear profile on an actual vehicle and simulating the same conditions on a powertrain test bench, with the establishment of a correlation in clutch wear profiles
Gear shifting effort or force especially in manual transmission has been one of the key factors for subjective assessment in passenger vehicle segment. An optimum effort to shift into the gears creates a big difference in overall assessment of the vehicle. The gear shifting effort travels through the transmission shifting system that helps driver to shift between the different available gears as per the torque and speed demand. The shifting system is further divided into two sub-systems. 1. Peripheral system [Gear Shift Lever with knob and shift Cable Assembly] and Shift system inside the transmission [Shift Tower Assembly, Shift Forks, Hub and sleeve Assembly with keys, Gear Cones and Synchronizer Rings etc.] [1]. Both the systems have their own role in overall gear shifting effort. There has been work already done on evaluation of the transmission shifting system as whole for gear shifting effort with typical test bench layouts. Also, work has been on assessment of life of the
This Recommended Practice is derived from OEM and tier-1 laboratory tests and applies to two-axle multipurpose passenger vehicles, or trucks with a GVWR above 4536 kg (10 000 pounds) equipped with hydraulic disc or drum service brakes. Before conducting testing for a specific brake sizes or under specific test conditions, review, agree upon, and document with the test requestor any deviations from the test procedure. Also, the applicable criteria for the final test results and wear rates deemed as significantly different require definition, assessment, and proper documentation; especially as this will determine whether or not Method B testing is needed. This Recommended Practice does not evaluate or quantify other brake system characteristics such as performance, noise, judder, ABS performance, or braking under extreme temperatures or speeds. Minimum performance requirements are not part of this recommended practice. Consistency and margin of pass/fail of the minimum requirements
ABSTRACT Presented are two designs for compact, low-profile UGVs with high cross-country mobility, intended for underbody operations with heavy manned vehicles. These UGVs are designed to remotely detect and assess combat damage incurred during combat operations, and analyze wear, leaks, and cracks, without the need for a human technician to be exposed to enemy fire, allowing crews to rapidly assess the conditions of their vehicles. Since robots required for underbody inspection would necessarily maintain a low, compact profile, they could also perform effective last-mile resupply in a contested environment, their small size allowing them to hide behind terrain and battlefield debris much more effectively than a heavy logistics robot. Naturally, a robotic vehicle that is capable of rapid underbody inspection of friendly vehicles or last-mile resupply could also be easily adapted as a combat platform to be used against enemy vehicles. Citation: A. Washington, et al., “Expendable Low
ABSTRACT The M1 Abrams will be the primary heavy combat vehicle for the US military for years to come. Improvements to the M1 that increase reliability and reduce maintenance will have a multi-year payback. The M1 engine intake plenum seal couples the air intake plenum to the turbine inlet, and has opportunities for improvement to reduce leakage and intake of FOD (foreign object debris) into the engine, which causes damage and premature wear of expensive components
Vehicular emissions represent the main responsible of the deterioration of air quality in the urban area. In the attempt to reduce both gaseous emissions and particulates from internal combustion engines, increasingly stricter regulations were introduced from European Union in the last years. These limits have led to the improvement of emissions-reduction technologies as well as the vehicle hybridization and electrification. In this scenario, vehicle emissions due to other sources rather than the propulsion systems, such as brakes and tires, have taken a significant weight. In this regard, European Commission has proposed the introduction in the next EURO 7 standard of the first-ever limit on the particles emitted by vehicle brakes. This study is devoted to improving the knowledge on the particle characteristics due to the brake wear by means of laboratory experiments thus providing support to the definition of the new standards. An experimental layout was realized consisting in a box
Abrasion of the Electromechanical brake (EMB) brake pad during the braking process leads to an increase in brake gap, which adversely affects braking performance. Therefore, it is imperative to promptly detect brake pad abrasion and adjust the brake gap accordingly. However, the addition of extra gap adjustment or sensor detection devices will bring extra size and cost to the brake system. In this study, we propose an innovative EMB gap active adjustment strategy by employing modeling and analysis of the braking process. This strategy involves identifying the contact and separation points of the braking process based on the differential current signal. Theoretical analysis and simulation results demonstrate that this gap adjustment strategy can effectively regulate the brake gap, mitigate the adverse effects of brake disk abrasion, and notably reduce the response time of the braking force output. Monitoring is critical to accurately control EMB clamping force. Pressure transducers are
The water droplet erosion (WDE) on high-speed rotating wheels appears in several engineering fields such as wind turbines, stationary steam turbines, fuel cell turbines, and turbochargers. The main reasons for this phenomenon are the high relative velocity difference between the colliding particles and the rotor, as well as the presence of inadequate material structure and surface parameters. One of the latest challenges in this area is the compressor wheels used in turbochargers, which has a speed up to 300,000 rpm and have typically been made of aluminum alloy for decades, to achieve the lowest possible rotor inertia. However, while in the past this component was only encountered with filtered air, nowadays, due to developments in compliance with tightening emission standards, various fluids also collide with the spinning blades, which can cause mechanical damage. One such fluid is the condensed water in the low-pressure exhaust gas recirculation channel (LP-EGR) formulated at cold
The manufacturing landscape is undergoing a transformation, propelled by the need for innovative, efficient, and precise technology that can effectively replace expensive manual labor. This article examines advancements in Flexiv’s material abrasion technology, specifically focusing on sanding and polishing applications and the utility of force control technology
Wheel hubs with drum brakes of heavy-duty vehicles rarely broke, but some suddenly cracked in the 2000s. The cause of damage was said to be a lack of hub strength. However, the case was suspicious because the hubs were produced according to the design guidelines by the JSAE. In the 1990s, brake shoe-lining materials were changed from asbestos to non-asbestos for people’s health. The brake squeal and abnormal self-lock frequently occurred because of the increased friction coefficient between drum and shoe lining in the case of the leading–trailing type. The mechanical friction coefficient changes with the material and the contact angle, which varies with the wear of shoe lining and the drum temperature. In the previous report, the deformation of the wheel hub under the abnormal self-lock was verified by observing the change of hub attitude in model test equipment. In this paper, a causality between the hub crack damage and the abnormal friction increase is clarified by predicting the
This specification covers a corrosion-resistant steel in the form of bars, wire, forgings, extrusions, mechanical tubing, flash-welded rings, and stock for forging, extruding, or flash-welded rings
Additive manufacturing (AM) is currently the most sought-after production process for any complex shaped geometries commonly encountered in Aerospace Industries. Although, several technologies of AM do exits, the most popular one is the Direct Metal Laser Sintering (DMLS) owing to its high versatility in terms of precision of geometries of components and guarantee of highest levels of reduction in production time. Further, metallic component of any complex shape such as Gas Turbine Blades can also be developed by this technique. In the light of the above, the present work focuses on development of iron silicon carbide (Fe-SiC) complex part for ball screw assembly using DMLS technique. The optimized process parameters, hardness and wear resistance of the developed iron-SiC composite will be reported. Further, since the material chosen is a metallic composite one, the effect of SiC on the thermal stresses generated during the DMLS processing of Fe-SiC composite will also be discussed. A
Recently, a Korean company donated a wearable robot, designed to aid patients with limited mobility during their rehabilitation, to a hospital. The patients wear this robot to receive assistance for muscle and joint exercises while performing actions such as walking or sitting. Wearable devices including smartwatches or eyewear that people wear and attach to their skin have the potential to enhance our quality of life, offering a glimmer of hope to some people much like this robotic innovation
Carburizing, austenitic, and boronizing were used to enhance the friction and wear properties of AISI 1080 and 1566 steel surfaces. They were subjected to austenitic, solid boronizing, liquid and gaseous carburizing processes. An examination done and observed the microstructure, X-ray diffraction patterns, and hardness distributions of the material. For the wear testing, pin-on-disc specimen topologies were employed, and removal efficiencies were estimated based on the sliding distance and the required force applied. In addition, the abrasiveness of the sample surfaces was assessed. The heat treatment capacity of AISI 1020 steel was investigated and compared to the heat treatment capabilities of other steel samples to establish how much heat can be applied to the steel
This study delves into the innovative realm of synthesizing surface alloyed materials by utilizing copper-based metamorphic powders subjected to high-intensity electron beam irradiation. The process involves depositing metamorphic particles onto a stainless-steel substrate, and subsequently exposing the assembly to a powerful electron beam, resulting in the development of distinct surface alloyed layers. A notable advancement was achieved by introducing a second layer of metamorphic powders over the existing alloyed layer, followed by further treatment with the electron beam. The alloyed layers, characterized by a volumetric concentration ranging from 60 to 67%, exhibited a fascinating phenomenon— the formation of abundant borate crystals with the chemical formula Al2.56Fe1.75Ni0.84. This crystal presence significantly elevated the hardness of the surface alloyed layers, showcasing an impressive five to sevenfold increase compared to the substrates. Importantly, the alloyed layers
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