Browse Topic: Protective structures
ABSTRACT Midé Technology Corporation (Midé), a Hutchinson company, in collaboration with The University of Texas at Austin (UTA), have investigated the potential for novel negative stiffness (NS)-based structures as blast resistant vehicle panels. Protecting vehicles from blast shockwaves would ideally minimize added weight and maximize reusability. Homogenous metal panels provide such protection but without the benefit of reusability, absorbing energy via plastic deformation, while also adding significant weight to a vehicle, thereby sacrificing mobility. Although various emergent approaches, including the use of hexagonal honeycombs and auxetic materials, have proved promising in terms of higher energy absorption per unit mass, such approaches also rely on plastic deformation additionally suffering from the drawback of occasionally transmitting a higher peak force as compared to the incident
ABSTRACT In this paper a new bolt attachment method was explored, where the attaching bolts were divided into two sets. The first set of bolts was tightened and was used to connect the underbody plate to the hull under ordinary operations. The second set of bolts connecting the plate and the hull were not tightened and had some extra axial freedom. Under blast loading, the first set of bolts would break due to high tensile and shear loads, but the second set of bolts would survive due to extra axial freedom which allows the plate and the hull vibrate and separate from each other to a certain extent. A simulation model was developed to verify this concept. Three underbody plate-hull connection approaches were simulated and analyzed: 1) all tightened bolts, 2) some bolts not fully seated, 3) all bolts not fully seated. The simulation results show that with option 1), 100% of the bolts broke under the blast loading. With option 2) the not fully seated bolts survived and continued to
ABSTRACT A functionally-graded NPR (Negative Poisson’s Ratio) material concept has been developed for a critical Army application – blast protection. The objective is to develop a combined computational design methodology and innovative structural-material concept for a blast-protective deflector, which can concentrate material into areas most needed and adapt its shape utilizing the blast energy to improve blast mitigation and crew protection. Included in the computational design methodology is optimal deflector shape design and optimal NPR material distribution to further improve the protection while minimizing the C.G. height of the vehicle and the weight of the deflector. Structures fabricated using this new concept react to the explosion and reconfigure themselves under the blast force to provide maximum blast protection. The presented research work consists of two basic approaches to deflector design: optimal deflector shape design and optimal NPR material configuration and
ABSTRACT In order to defeat under body blast events and improve crew survivability, a monocoque aluminum cab structure has been designed as a drop on solution based on the current M1151A1 (HMMWV) chassis. The structure is comprised of all 5083-H131 Aluminum alloy armor plates with various thicknesses. The structure design consists of the following new features: (1) Robust joining design utilizing interlocking ballistic joints and mechanical interlocking features, (2) unique B-pillar gusset design connects roof & floor with B-pillar & tunnel, and (3) “Double V” underbody shaping design. The TARDEC designed, integrated & built vehicle achieved no crew core body injuries for a vehicle of this weight class and demonstrated meeting the crew survivability objective when subjected to a 2X blast during the live fire underbody blast tests. These efforts help to not only baseline light tactical vehicle capabilities, but also validate the possibility of meeting aggressive blast objectives for
This SAE Standard is intended to provide personnel protection guidelines for skid steer loaders. This document is intended as a guide towards standard practice, 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. This document provides performance criteria for newly manufactured loaders and it is not intended for in-service machines
In the automotive industry, the electric vehicle is the new era, and companies are committed to reducing carbon emissions by electrification of their vehicles. In the development of electric vehicles, the battery is the central power source for all the parts of the vehicle. Usually, it is placed under the body because of its size and mass. So, it is important to protect battery cells from leakage and damage from obstacles. For on-road electric vehicles, speed bumps are one of the crucial obstacles. This paper investigates and analyses the protection of battery pack systems in electric vehicles while encountering speed bump profiles at different speeds. During the physical test on a speed bump, there is a possibility of bump hit on the battery pack system and it is necessary to ensure the structural safety of the battery pack systems. In this study, CAE method has been developed to validate the battery pack system in the event of a speed bump crossing. Virtual simulation analysis was
This SAE Standard applies to all forestry machines exposed to the hazard of objects penetrating the front of the operator station (other than the roof). This would include
This specification covers established inch/pound manufacturing tolerances applicable to copper and copper alloy sheet, strip, and plate ordered to inch/pound dimensions. These tolerances apply to all conditions, unless otherwise noted
This SAE Recommended Practice applies only to excavators, as defined in ISO 6165, working above ground, near an excavated or free-standing bank or mine face which is higher than the top of the cab, or in demolition applications of freestanding buildings or objects higher than the top of the cab
This SAE Standard defines the safety and performance requirements for low-speed vehicles (LSVs). The safety specifications in this document apply to any powered vehicle with a minimum of four wheels, a maximum level ground speed of more than 32 km/h (20 mph) but not more than 40 km/h (25 mph), and a maximum gross vehicle weight of 1361 kg (3000 pounds), that is intended for operating on designated roadways where permitted by law
This SAE Standard defines requirements relating to the elements of design, operation, and maintenance of light utility vehicles (LUVs). The safety specifications in this document apply to any self-propelled, operator-controlled, off-highway vehicle 1829 mm (72 inches) or less in overall width, exclusive of added accessories and attachments, operable on three or more wheels or tracks, primarily intended to transport material loads or people, with a gross vehicle weight of 2500 kg (5500 pounds) or less, and a maximum design speed less than or equal to 40.23 km/h (25 mph). This document is not intended to cover go-karts (ASTM F2007-07a), fun-karts (ASTM F2011-02e1), dune buggies, and all terrain-vehicles (ATVs) complying with ANSI/SVIA 1
This SAE Standard establishes the minimum performance requirements for pelvic restraint systems (seat belts, anchorages, and the fastening elements of seat belts) necessary to restrain an operator or rider within a roll-over protective structure (ROPS) in the event of a machine roll-over, as defined in ISO 3471, ISO 8082-1, ISO 8082-2, ISO 12117-2, and ISO 13459, or tip-over protection structure (TOPS), in the event of a machine tip over as defined in ISO 12117. This standard provides guidance and recommendations for information included in the machine operator manual
This SAE Recommended Practice applies only to excavators, as defined in ISO 6165, working above ground, near an excavated or free-standing bank or mine face which is higher than the top of the cab, or in demolition applications of free standing buildings or objects higher than the top of the cab
The scope of this document is to provide an overview of the techniques found in the published literature for rollover testing and rollover crashworthiness evaluation at the vehicle and component levels. It is not a comprehensive literature review, but rather illustrates the techniques that are in use or have been used to evaluate rollover crashworthiness-related issues
AS5259 covers design requirements, performance requirements, and methods of procurement for tools and associated accessories used to crimp wire barrels of aircraft electrical wiring components including ferrules, terminals, splices, and connector contacts on wire/cable sizes 8 to 4/0
This SAE Standard applies to self-propelled, rider operated sweepers and scrubbers as defined in SAE J2130 with maximum machine level surface speeds up to 32 km/h. Machines capable of speeds equal to and greater than 32 km/h are not covered by this document
Off-road trucks, tractors and earth-moving machines are at high risk of accidents involving falling objects or rollovers. Therefore, these machines need proper protective structures to protect operators. This study investigates the crashworthiness optimization of a hydraulic excavator cab roof rail based on an improved bi-directional evolutionary structural optimization (BESO) method considering two different load cases (a lateral quasi-static load and an impact load from the top of cab, respectively). In the crashworthiness optimization problem, a weighted summation of external works done by the two different load cases is treated as the objective function while the volume of design domain is treated as the constraint. A mutative weight scheme is proposed to stabilize the optimization and balance the two load cases. Finite element (FE) model is established and two prototypes are fabricated based on the optimal design. Explicit FE analysis is used to predict the performance of roll
An All-Terrain Vehicle (ATV) as defined by the American National Standards Institute (ANSI) is a vehicle that travels on low pressure tires and with a seat that is straddled by the operator, along with the handlebars for steering control. A roll cage can be defined as a skeleton of an ATV. It forms a structural base and 3-D shell around the driver. In case of impacts and roll over incidents, the roll cage is responsible for the protection of driver. The objective is to design, analyze and optimize the roll cage under a set of particular rules given by Society of Automotive Engineers (SAE). The static analysis is carried out using CATIA V5 software for different collisions like front, side, rear and roll over. The main objective of the analysis is to obtain a roll cage enough strong to bear such adverse conditions as well as light in weight for better performance. The safety of roll cage can be ensured by obtaining optimum factor of safety
Tractor roll over is the most common farm-related cause of fatalities nowadays. ROPS (Roll-Overprotective Structures) are needed to prevent serious injury and death. It creates a protective zone around the operator when a rollover occurs. In India the ROPS is getting mandatory across all HP ranges except narrow track. In the present study states the customized ROPS application for configurable design such as Automated safety zone for all homologation standards, ROPS A0-D excel calculator for selection of material at concept stage and bolt calculator for selection of size. For the above applications below aspects need to consider such as Tractor weight, Rear housing mounting, Operator seat index position (SIP), Seat reference points (SRP) and all ROPS homologation standards. This ROPS application is to reduce the timeline, manual error and ensure the reliability of the modular optimal design for various platforms and variants. Nowadays it is important to perform configurable design at
Tractor weight transfer is the most common farm-related cause of fatalities nowadays. As in India it is getting mandatory for all safety devices across all HP ranges. Considering any changes in the weight from an attachment such as Rops, PTO device, tow hook and draw bar etc. can shift the center of gravity towards the weight. center of gravity is higher on a tractor because the tractor needs to be higher in order to complete operations over crops and rough terrain. Terrains, attachments, weights, and speeds can change the tractor’s resistance to turning over. This center of gravity placement disperses the weight so that 30 percent of the tractor’s weight is on the front axle and 70 percent is on the rear axle for two-wheel drive propelled tractors and it must remain within the tractor’s stability baseline for the tractor to remain in an upright position. In our present study formulating the prediction of tractor CG by using a modified excel spreadsheet package employing the parameters
NASA Goddard Space Flight Center has developed a magnetic shielding design that features simplicity, ease of use, reproducibility, longevity, and scalability. It does not require activation, monitoring, or wiring. The invention uses the superconducting “proximity effect” and/or the “inverse proximity effect” to form a spatially varying order parameter. When designed to expel magnetic flux from a region of space, the proximity effect(s) are used in concert to make the superconducting order parameter strongly superconducting in the center and more weakly superconducting toward the perimeter. The shield is then passively cooled through the superconducting transition temperature
To protect ship equipment of river and sea transport, it is suggested to use polymeric protective coatings based on epoxy diane oligomer ED-20, polyethylene polyamine (PEPA) curing agent and filler, which is a departure from industrial production. Thus the purpose of the work is analysis of major dependency of the properties on the content of fillers that allowed to revealed the critical filler content (furnace black) in composites to form a protective coating with the required set of characteristics. The infrared (IR) spectral analysis was used to investigate the presence of bonds on the surface of particles of the PM-75 furnace black, which allows us to assess the degree of cross-linking of the polymer. The influence of the content of dispersed furnace black on the physicomechanical and thermophysical properties and the structure of the protective coating is investigated. For the formation of the coating with increased adhesive properties, the optimum content of the additive is q
This SAE Recommended Practice applies to three-point hitch (Type A) backhoes as defined in SAE J326 when mounted on either an agricultural tractor as defined in ANSI/ASAE S390 or other off-road self-propelled work machine as defined in SAE J1116. This criterion is intended for the manufacturer of the backhoe, whether or not the backhoe is manufactured or marketed by the same company that manufactures or markets the propelling machine
This SAE Standard is intended to provide personnel protection guidelines for skid steer loaders. This document is intended as a guide towards standard practice, 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. This document provides performance criteria for newly manufactured loaders and it is not intended for in-service machines
This standard covers self-propelled off-road work machines as categorized in SAE J1116 and Agricultural Tractors as defined in ANSI/ASAE S390
These general operator precautions apply to off-road work machines as defined in SAE J1116, and Agricultural Tractors as defined in ANSI/ASAE S390, Nov 2004. These should not be considered as all-inclusive for all specific uses and unique features of each particular machine. Other more specific operator precautions not mentioned herein should be covered by users of this recommended practice for each particular machine application
This paper discusses a simplified analytical/experimental method for evaluating and designing large buses and motor coaches for rollover protection. The proposed method makes use of the work-energy principle in analyzing the energy-absorbing capacity of the roof and sidewall structure of the vehicle. The basic structural unit is treated as a nonlinear, elastoplastic, 4-bar linkage, with the links connected at hinge points. During rollover, the deformation of the structure is focused at these hinge points and energy absorption is achieved through plastic bending and rotation of the hinge material. The proposed method allows the evaluation and design of these plastic hinges to achieve the energy-absorbing requirements for the vehicle. This paper demonstrates the proposed methodology by evaluating an exemplar large bus design against the European ECE-R.66 rollover design standard. This same vehicle was similarly evaluated in a referenced study, using the finite element analysis (FEA
This SAE Aerospace Recommended Practice (ARP) defines the nomenclature of temperature measuring devices. General temperature measurement related terms are defined first, followed by nomenclature specific to temperature measuring devices, particularly thermocouples
Finite Element Analysis (FEA) is a numerical method to find solutions to real world problems and is now commonly used for product development. Various finite element analyses are performed to validate the system performance. Many finite element codes are also available for this purpose. Now-a-days, product development not only deals with the validation of design performance, but also focuses on design optimization. Methods such as one-factor-at-a-time (OFAT) experiments are generally used in which one input factor is varied at a time and its effect on system performance is studied. Design of Experiments (DOE) is a systematic approach in which more than one input factors are purposefully varied to study their effect on system performance. Finite Element Analysis and Design of Experiments approach can be used in combination for design optimization. This paper deals with the process for design optimization that can be followed using FEA and DOE in conjunction. This methodology is
Items per page:
50
1 – 50 of 288