Browse Topic: Polymers
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
The purpose of this SAE Recommended Practice is to establish guidelines for the automatic transmission and hydraulic systems engineer to design rectangular cross section seals for rotating and static grooved shaft applications. Also included are property comparisons of polymeric materials suitable for these applications. Historically, material covered in this document is not intended to include aluminum contact applications
A silicone membrane for wearable devices is more comfortable and breathable thanks to better-sized pores made with the help of citric acid crystals. The new preparation technique fabricates thin, silicone-based patches that rapidly wick water away from the skin. The technique could reduce the redness and itching caused by wearable biosensors that trap sweat beneath them. The technique was developed by bioengineer and professor Young-Ho Cho and his colleagues at KAIST and reported in the journal Scientific Reports
Automotive electrical and electronics manufacturer MTA attended IAA Transportation for the first time, demonstrating its new range of wireless communication technologies for the truck industry. Earlier this year, the company acquired Calearo Antenne S.p.A, a company with a long history of producing antennas, amplifiers and cables. MTA global sales director Davide Bonelli explained to Truck & Off-Highway Engineering how that acquisition complements its business. “From a more strategic point of view, we see the world of antennas as complementary to what MTA does,” he said. “Often MTA products have an antenna as an interface, so this is one reason why we have done the deal. There are also a lot of synergies from an engineering standpoint. Historically, MTA is a company that uses many mechanical parts - plastics, metals - which we are very strong with so we can share them. And there are also some competences from Calearo Antenne that can be transferred to us
The information in this document is intended to apply to commercial jet transport category airplanes that incorporate plastic (polycarbonate or acrylic) lenses on exterior light assemblies, or are being considered for such an application as opposed to glass lens designs. Exterior lighting applications include position light assemblies, anticollision light asemblies, and landing light assemblies. However, much of the material provided herein is general in nature and is directly applicable to many aircraft categories including, but not limited to, helicopters, general aviation aircraft, and military aircraft
This SAE Aerospace Information Report (AIR) summarizes data and background relative to age control of specific classes of those nitrile type synthetic elastomers used in sealing devices which are resistant to petroleum base hydraulic fluids, lubricating oils, and aircraft fuels. This includes, but is not limited to, those nitrile (NBR or BUNA-N) elastomers previously covered by Section I of MIL-STD-1523
ABSTRACT A 3D printed battery bracket is strengthened via post-print thermal annealing, demonstrating a transitionable approach for additive manufacturing of robust, high performance thermoplastic components. Citation: E. D. Wetzel, R. Dunn, L. J. Holmes, K. Hart, J. Park, and M. Ludkey, “Thermally Annealed, High Strength 3D Printed Thermoplastic Battery Bracket for M998,” In Proceedings of the Ground Vehicle Systems Engineering and Technology Symposium (GVSETS), NDIA, Novi, MI, Aug. 16-18, 2022
ABSTRACT Fiber reinforced thermoset composites are well known for delivering 50% or more weight savings when compared with steel components while also providing strength, stiffness, and toughness. Nanoparticle additives have been shown to significantly increase the mechanical properties of thermoplastic and thermoset polymer matrices over the base matrix values. Extensive testing and characterization of composites containing graphene nanoplatelets (GnP) has been conducted and reported by XG Sciences’ (XGS) collaborators at the Michigan State University (MSU) Composite Materials and Structures Center. In a recent program with U.S. Army Tank Automotive Research, Development and Engineering Center (TARDEC), MSU investigated lightweight composites for blast and impact protection. High strain rate test facilities as well as high speed photography and non-destructive interferometry-based evaluation techniques were used to evaluate blast performance. The experimental results are presented
ABSTRACT Militaries worldwide are increasing their Research and Development (R&D) into RAS. Within the next 10 – 15 years RAS will play an active part in operations as the future battlefield becomes more complex. CRT technology can significantly reduce platform weight, fuel consumption, noise and vibration levels[1][2][3]. Armies and vehicle manufacturers have initiated a series of independent trials that confirmed the benefits and reliability of CRT on a tracked military vehicle. With the increase in RAS technologies comes a desire to utilize the proven benefits identified from manned platforms. The author’s objective is to highlight the findings of these trials[1][2][3] and provide substantiated data on how CRT technology can benefit RAS in terms of weight saving, whilst reducing maintenance and vibration. Citation: Fabien Lagier, Ing. MBA, “Composite Rubber Track (CRT) for Robotic & Autonomous System (RAS)”, In Proceedings of the Ground Vehicle Systems Engineering and Technology
ABSTRACT High life cycle costs coupled with durability and environmental challenges of tracked vehicles in South West Asia (SWA) have focused R&D activities on understanding failure modes of track components as well as understanding the system impacts on track durability. The durability limiters for M1 Abrams (M1, M1A1, and M1A2) T-158LL track systems are the elastomeric components. The focus of this study is to review test methodology utilized to collect preliminary data on the loading distribution of a static vehicle. Proposed design changes and path forward for prediction of durability of elastomers at the systems level from component testing will be presented
ABSTRACT In this study, a styrene butadiene rubber, which is similar to the rubber used in road wheel backer pads of tracked vehicles, was investigated experimentally under monotonic and fatigue loading conditions. The monotonic loading response of the material was obtained under different stress states (compression and tension), strain rates (0.001/s to 3000/s), and temperatures (-5C to 50C). The experimental data showed that the material exhibited stress state, strain rate and temperature dependence. Fatigue loading behavior of the rubber was determined using a strain-life approach for R=0.5 loading conditions with varying strain amplitudes (25 to 43.75 percent) at a frequency of 2 Hz. Microstructural analysis of specimen fracture surfaces was performed using scanning electron microscopy and energy dispersive x-ray spectroscopy to determine the failure mechanisms of the material. The primary failure mechanisms for both loading conditions were found to be the debonding of particles on
ABSTRACT The first part of this paper will outline the conception of the testing apparatus (Figure 1), along with its operation and preliminary results. The second part of the paper will discuss a new methodology used to correlate the dependence of crack growth rate for strain crystallizing natural rubbers in terms of tearing energy. The tearing energy which depends on the type of elastomer, geometry and stress strain behavior of a particular specimen demonstrates a direct correlation with the crack growth rate at different R-ratios (= min tearing energy/max tearing energy). Figure 1 Schematic of the testing apparatus
This work aims to define a novel integration of 6 DOF robots with an extrusion-based 3D printing framework that strengthens the possibility of implementing control and simulation of the system in multiple degrees of freedom. Polylactic acid (PLA) is used as an extrusion material for testing, which is a thermoplastic that is biodegradable and is derived from natural lactic acid found in corn, maize, and the like. To execute the proposed framework a virtual working station for the robot was created in RoboDK. RoboDK interprets G-code from the slicing (Slic3r) software. Further analysis and experiments were performed by FANUC 2000ia 165F Industrial Robot. Different tests were performed to check the dimensional accuracy of the parts (rectangle and cylindrical). When the robot operated at 20% of its maximum speed, a bulginess was observed in the cylindrical part, causing the radius to increase from 1 cm to 1.27 cm and resulting in a thickness variation of 0.27 cm at the bulginess location
This specification covers a silicone (MQ/VMQ/PVMQ) elastomer that can be used to manufacture product in the form of sheet, strip, tubing, extrusions, and molded shapes. This specification should not be designated for use in molded O-rings and molded O-ring cord, molded rings, compression seals, molded-in-place gaskets, and plate seals for aeronautical and aerospace applications
Anne-Marie Vincent Dow Silicones Belgium SRL Seneffe, Belgium
A flexible and stretchable cell has been developed for wearable electronic devices that require a reliable and efficient energy source that can easily be integrated into the human body. Conductive material consisting of carbon nanotubes, crosslinked polymers, and enzymes joined by stretchable connectors, are directly printed onto the material through screenprinting
Inspired by the paper-folding art of origami, North Carolina State University engineers have discovered a way to make a single plastic cubed structure transform into more than 1,000 configurations using only three active motors. The findings could pave the way for shape-shifting artificial systems that can take on multiple functions and even carry a load — like versatile robotic structures used in space, for example
Imagine if physicians could capture three-dimensional projections of medical scans, suspending them inside an acrylic cube to create a hand-held reproduction of a patient’s heart, brain, kidneys, or other organs. Then, when the visit is done, a quick blast of heat erases the projection, and the cube is ready for the next scan
In the future, power sockets used to recharge smartphones, tablets, and laptops could become obsolete. The electricity would then come from our own clothes. By means of a new polymer that is applied on textile fibers, clothing could soon function as solar collectors and thus as a mobile energy supply
This specification covers two types of virgin, unfilled polytetrafluoroethylene (PTFE) in the form of molded rods, tubes, and shapes. This specification does not apply to product over 12 inches (305 mm) in length, rods under 0.750 inch (19.05 mm) in diameter, and tubes having wall thickness under 0.500 inch (12.70 mm
This specification covers virgin, unfilled polytetrafluoroethylene (PTFE) in the form of molded rods, tubes, and shapes. This specification does not apply to product over 12 inches (305 mm) in dimension parallel to the direction of applied molding pressure, rods under 0.750 inch (19.05 mm) in diameter, and tubes having wall thickness under 0.500 inch (12.70 mm
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