Browse Topic: Materials testing
ABSTRACT V-shaped hulls for vehicles, to mitigate buried blast loads, are typically formed by bending plate. Such an approach was carried out in fabricating small test articles and testing them with buried-explosive blast load in Southwest Research Institute’s (SwRI) Landmine Test Fixture. During the experiments, detailed time dependent deflections were recorded over a wide area of the test article surface using the Dynamic Deformation Instrumentation System (DDIS). This information allowed detailed comparison with numerical simulations that were performed with LS-DYNA. Though in general there is good agreement on the deflection, in the specific location of the bends in the steel the agreement decreases in the lateral cross section. Computations performed with empirical blast loads developed by SwRI and by more computationally intensive ALE methods in LS-DYNA produced the same results. Computations performed in EPIC showed the same result. The metal plate was then bent numerically so
ABSTRACT For this particular effort, TARDEC Center for Systems Integration (CSI) was tasked to lead an effort to develop an underbody kit that would serve multiple functions. The underbody kit would provide an additional 1,200 lbs of net buoyancy to enhance water mobility per the LAV. This program is in the development and testing phase with a prototype expected to be produced June of 2015. This program is one of multiple efforts to ensure the FOLAV meet all system requirements to keep the vehicle viable to 2035. In addition, the TARDEC concept/prototype must meet the same mine blast protection provided by the underbody D-Kit that was produced for the fleet of vehicles in 2010. This is a unique challenge as a combination of buoyancy, mine blast, and structural requirement on a ground military vehicle is novel idea. Vehicle weight and survivability requirements are difficult challenges on combat vehicles, to include the LAV, so the TARDEC solution would have to reduce the weight of the
ABSTRACT This paper addresses candidate technologies for attaching steels to selected lightweight materials. Materials of interest here include aluminum and titanium alloys. Metallurgical challenges for the aluminum-to-steel and titanium-to-steel combinations are first described, as well as paths to overcome these challenges. Specific joining approaches incorporating these paths are then outlined with examples for specific processes. For aluminum-to-steel joining, inertia, linear, and friction stir welding are investigated. Key elements of success included rapid thermal cycles and an appropriate topography on the steel surface. For titanium-to-steel joining, successful approaches incorporated thin refractory metal interlayers that prevented intimate contact of the parent metal species. Specific welding methods employed included resistance mash seam and upset welding. In both cases, the process provided both heat for joining and a relatively simple strain path that allowed significant
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
Military performance requirements for adhesives have been traditionally derived to fulfill niche defense needs in harsh operational environments with little consideration for dual-use commercial potential. U.S. Army Research Laboratory, Aberdeen, MD The term “military-grade” can have a variety of meanings that are perspective dependent. In 2014, Ford Motor Company emphasized the term heavily in advertising campaigns to garner consumer acceptance for the transition from steel to aluminum in the body of their flagship F150 model. As cited by Ford, “Engineers selected these high-strength, military-grade aluminum alloys because of the metals' unique ability to withstand tough customer demands.” From this point-of-view, military-grade implies superior performance. However, the bureaucratic and logistical barriers required for certification to military-grade acceptance levels per DoD performance requirements can also be perceived as impediments to innovation and the transition of fundamental
Composites are increasingly being used in aerospace and defense parts manufacture for several reasons including the high strength to weight ratio of materials, and due to the fuel savings generated by their lighter weight. Force measurement and material testing is an essential process for product designers and manufacturers to ensure part integrity, and to gain insightful data for creating the highest quality composite components
This specification covers powdered metal products consolidated by hot isostatic pressing (HIP) of titanium alloy powder compacts
This SAE Recommended Practice presents recommendations for test fuels and fluids that can be used to simulate real world fuels. The use of standardized test fluids is required in order to limit the variability found in commercial fuels and fluids. Commercial fuels can vary substantially between manufacturers, batches, seasons, and geographic location. Further, standardized test fluids are universally available and will promote consistent test results for materials testing. Therefore, this document: a Explains commercial automotive fuel components b Defines standardized components of materials test fluids c Defines a nomenclature for test fluids d Describes handling and usage of test fuels e Recommends fluids for testing fuel system materials The test fluid compositions specified in Section 7 of this document are recommended solely for evaluating materials. They are not intended for other activities, such as engine development, design verification, or process validation unless agreed
14-day material test to determine the cyclic effects of runway deicing compounds on cadmium plated parts
The static coefficient of friction between lining and shoe plays a fundamental role in the lining fixing project, which is the most important parameter for the riveted joint calculation. For the lining riveting, the rivet needs to ensure that friction material and shoe remain in contact through the normal force applied on the surfaces, but the rivet should not be exposed to shear forces. Thus, the brake torque transmission must occur through the static coefficient of friction between lining and shoe, not allowing relative slips or movements between the pair in contact. Therefore, the present study aims to understand the influence of the static friction coefficient between lining and shoe as a function of the lining internal superficial roughness, from the evaluation of different roughness conditions - contact area with shoe -. The static coefficient of friction between lining and shoe is a complex measurement to be performed, due to the cylindrical geometry of the drum brake system, so
Brakes are the critical component, plays a significant role regards to performance of vehicle. Vehicle safety is also strongly influenced by proper braking operation, which depends on pad to disc contact interface. Pad and disc surfaces are worn out due to continuous braking events, which in turn affects the life of the brake assembly and its performance. This paper presents the brake pad wear prediction of a disc brake assembly. A new and unworn pair of brake pads are considered for the study and tested under different braking scenarios. Wear simulation procedure is formulated based on Rhee’s wear formula and wear calculation model is established based on friction and wear mechanism. The correlation between the wear behavior of a friction material tested under controlled laboratory conditions and finite element method is investigated. Based on the calculated wear, lifespan of the brake pad is also calculated. The predicted life of the pad using inertia brake dynamometer (IBD) is then
This SAE Aerospace Standard (AS) specifies solid polytetrafluoroethylene (PTFE) retainers (backup rings) for use in static glands in accordance with AS5857. They are usually for use in hydraulic and pneumatic systems as anti-extrusion devices in conjunction with O-rings and other seals. NOTE: This specification includes material tests but does not include hydraulic or pneumatic performance tests
The steering knuckle is an essential component in All-Terrain Vehicle (ATV) which withstands alternating loads subjected to different conditions without affecting the vehicle performance. The main objective of the proposed work was to design and analysis the steering knuckle under static conditions to observe stress, total deformation and factor of safety for proposed materials. In this present investigation, Aluminium alloy (AA7075) was chosen as it exhibits good ductility, high strength, toughness and high resistance to withstand impact load. The prime objective of this work was processed under three different conditions like virgin AA7075, AA7075 with T6 heat treatment and AA7075 with T6 heat treatment followed by shot-peening post processed technique was completed and to attain diverse strength of the samples were tested and noted appropriate responses. The secondary objective of our proposed work, an optimum knuckle design was modeled using Solidworks. The proposed materials test
This SAE Recommended Practice is intended as the definition of a standard test, but may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use. The SAE No. 2 Friction Test Machine is used to evaluate the friction characteristics of automatic transmission plate clutches with automotive transmission fluids. It can also be used to conduct durability tests on wet friction systems. The specific purpose of this document is to define a 6000 rpm stepped power test for the evaluation of wet friction system performance variation as a function of power level. This procedure uses an initial engagement speed of 6000 rpm and is intended as a standard procedure for common use by both suppliers and end users. The only variables selected by the supplier or user of the friction system are: a Friction material b Fluid c Reaction plates These three variables must be clearly identified when reporting the results of using this
This SAE Recommended Practice is intended as the definition of a standard test, which may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use. The SAE No. 2 Friction Test Machine is used to evaluate the friction characteristics of automatic transmission plate clutches with automotive transmission fluids. It can also be used to conduct durability tests on wet friction systems. The specific purpose of this document is to define a μPVT Test for the evaluation of the variation of wet friction system performance as a function of speed, temperature, and pressure. This procedure is intended as a standard for both suppliers and end users. The only variables selected by the supplier or user of the friction system are: a Friction material b Fluid c Reaction plates These three variables must be clearly identified when reporting the results of this test. If any of the test parameters or system hardware as described
This SAE Recommended Practice is intended as the definition of a standard test, but may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use. The SAE No. 2 Friction Test Machine is used to evaluate the friction characteristics of automatic transmission plate clutches with automotive transmission fluids. It can also be used to conduct durability tests on wet friction systems. The specific purpose of this document is to define a 3600 rpm Stepped Power Test for the evaluation of wet friction system performance variation as a function of power level. This procedure uses an initial engagement speed of 3600 rpm and is intended as a standard procedure for common use by both suppliers and end users. The only variables selected by the supplier or user of the friction system are: a Friction Material b Fluid c Reaction Plates These three variables must be clearly identified when reporting the results of using this
This test method is intended for measuring fuel permeation at elevated temperature through low permeating hose or tubing samples of elastomeric or composite construction. The expected accuracy of the method is about ±10% of the sample permeation rate. Hose permeation testing can be done two ways: Method A – Plug and Fill or Method B – using a fuel reservoir. Method A involves plugging one end of the hose, filling the sample to about 90% full with test fuel, plugging the other end, and then exposing the plugged sample to a desired test temperature, with the weight loss measured over time. Method B involves plugging one end of a hose, and then connecting the other end to a fuel reservoir. The hose sample and reservoir are then exposed to a desired test temperature with the weight loss measured over time. This procedure presents a recommended plug design that permits inserting the plugs prior to adding the test fluid. One of the plugs has a small fill hole with a gasketing system that
Engineering Stress, also known as Nominal Stress, is used in material testing, to quantify load carrying characteristics and abilities, such as ultimate tensile strength (UTS), modulus of rupture (under bending), yield strength, etc. Standard testing, however, is limited to regular cross-section shapes (rectangular, circle, etc.). In engineering applications, however, geometry and loading are typically much more complex. While FEA can be used to calculate local stress concentrations, the underlying Nominal Stress is not known. This paper introduces a method to calculate nominal stresses, based on FEA element nodal forces. Internal testing results of FCD500 (common material for brake components) bars, with and without notches, will be presented. Corresponding Nominal Stresses and local stress concentrations will be discussed, along with testing results
14-day material test to determine the cyclic effects of runway deicing compounds on cadmium plated parts
A reduction in brain disorders owing to traumatic brain injury (TBI) caused by head impacts in traffic accidents is needed. However, the details of the injury mechanism still remain unclear. In past analyses, brain parenchyma of a head finite element (FE) model has generally been modeled using simple isotropic viscoelastic materials. For further understanding of TBI mechanism, in this study we developed a new constitutive model that describes most of the mechanical properties in brain parenchyma such as anisotropy, strain rate dependency, and the characteristic features of the unloading process. Validation of the model was performed against several material test data from the literature with a simple one-element model. The model was also introduced into the human head FE model of THUMS v4.02 and validated against post-mortem human subject (PMHS) test data about brain displacements and intracranial pressures during head impacts. Additionally, several parametric studies were performed to
Instron (Norwood, MA) manufactures materials testing equipment and accessories that are used to test samples ranging from components for jet engines to medical syringes. The company’s ElectroPuls systems are used for fatigue testing, which examines the behavior of materials under fluctuating or cyclic loads in the elastic regime. The E1000, E3000, and E10000 fatigue test systems are suited for biomedical/biomechanical research applications, and feature a wide dynamic performance range and low force characteristics. The all-electric systems use linear motor technology to eliminate the need for ball/lead-screws, and enable slow-speed static tests through to high-frequency dynamic tests at over 100 Hz
Acoustic material testing is becoming increasingly relevant to engineers, designers and manufacturers from a broad range of industries. This paper presents comparisons between material absorption measurements made using the traditional approaches of the reverberation room method and the fixed impedance tube using a sample holder, with those obtained using a lightweight portable flanged impedance tube method. The portable tube allows fast non-destructive in-situ material measurements. It may therefore be used to measure the impact of the installed lay-up (e.g. effects of facing sheets, curvature, material compression, bagging, etc.). Results are presented for both non-locally reacting and locally reacting materials. The flanged tube results are compared directly with in-tube data. They are also corrected for random incidence to allow comparison with the diffuse field reverberation room data. It is concluded that the flanged portable impedance tube method provides an attractive
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