Browse Topic: Polymers
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 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 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 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
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 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 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
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
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
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
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
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 sheet manufactured by compression molding and sintering
This SAE Aerospace Recommended Practice (ARP) provides an overview of the various types of polytetrafluoroethylene (PTFE) backup rings for hydraulic and pneumatic fluid power applications, including their advantages and disadvantages
This SAE Aerospace Recommended Practice (ARP) describes the etching of fluoropolymer electrical wire insulations to ensure that all facets of the process from the chemistry to the processing, to the storage and handling are well defined
Eight arguments for these resins, compounds and composites. Weight reduction in EV battery components is an important factor in optimizing battery energy density, which in turn is critical to extending vehicle range and boosting power and performance. Although traditional metals such as steel and aluminum are widely used in EV batteries, the ongoing push for higher energy density is opening new opportunities for thermoplastic resins, compounds, and composites. The main advantage of these materials vs. metals is their inherent lighter weight - particularly in the case of lower-density polymers. Thermoplastics can be 30-50 percent lighter than metals. They also increase design freedom, which permits further weight-out through part consolidation and thin walls
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
Silicone elastomers have become a vital material in the medical device industry due to their unique properties, including biocompatibility, durability and chemical inertness. Silicone materials are categorized based on their unvulcanized consistency, which significantly affects their processability and their physical properties. This article compares high consistency silicone rubbers (HCRs), liquid silicone rubbers (LSRs), and low consistency elastomers (LCEs), analyzing their characteristics and the implications in selecting each during different phases in the development of silicone medical devices
Georgia Tech researchers are using artificial intelligence to accelerate materials discovery. Georgia Tech University, Atlanta, GA Nylon, Teflon, Kevlar. These are just a few familiar polymers - large-molecule chemical compounds - that have changed the world. From Teflon-coated frying pans to 3D printing, polymers are vital to creating the systems that make the world function better. Finding the next groundbreaking polymer is always a challenge, but now Georgia Tech researchers are using artificial intelligence (AI) to shape and transform the future of the field. Rampi Ramprasad's group develops and adapts AI algorithms to accelerate materials discovery
Nylon, Teflon, Kevlar. These are just a few familiar polymers — large-molecule chemical compounds — that have changed the world. From Teflon-coated frying pans to 3D printing, polymers are vital to creating the systems that make the world function better
This document establishes age limit and guidance for acceptance of hose and hose assemblies containing elastomeric materials for use in aircraft, space vehicles, missiles and component assemblies thereof at time of delivery to the contractor, procuring activity, or contracting officer. This document does not establish limitations on storage times for military/civil activities nor operating life
This specification covers a fluorocarbon (FKM) rubber in the form of O-rings, O-ring cord, compression seals, and molded-in-place gaskets for aeronautical and aerospace applications
Arsenic and ammonia in ground and surface waters pose significant health risks globally, especially for remote areas where access to safe drinking water is a concern for U.S. military personnel. Current removal materials and methods lack contaminant specificity. This study developed adsorptive resins and membranes specifically targeting arsenate and ammonia removal using molecularly imprinted acrylate polymers supported on graphitic carbon nitride. These materials showed comparable arsenate removal capacity to commercial resins. Higher ammonia removal capacity but lower selectivity was demonstrated by these materials in comparison to commercial resins. This research aims to enhance water treatment materials for ensuring clean drinking water access in remote military locations
This specification covers a fluorosilicone (FVMQ) elastomer that can be used to manufacture product in the form of sheet, strip, tubing, extrusions, and molded shapes. This specification should not be used for molded rings, compression seals, molded O-rings, molded O-ring cord, and molded-in-place gaskets for aeronautical and aerospace applications
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