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This paper presents the National Crash Survival Data Bank (NCSDB), a data base of impact acceleration test data available to researchers and modelers. We emphasize the contents and implementation of the NCSDB, a web-accessible object-relational data base housed at the National Biodynamics Laboratory (NBDL). Past and potential modeling applications of the data stored in the NCSDB are discussed.

With the increased number of airbags and other advanced restraint systems, the upper and lower extremities are becoming more widely studied to determine the injury potential from these devices. However, little injury tolerance data exist for whole bones. To address this deficiency, a finite element model of a female upper extremity was created from computed tomography scan data. A constant density of 1.86 g/cm3 was assumed with a previously developed transversely isotropic, elastic- plastic material model that incorporates rate effects through a modification to the longitudinal modulus and yield stress. Qualitative simulations were conducted for tension, compression, and torsion along the long axis of the bone and for three-point bending in the anterior-posterior direction. Failure was shown to occur in the area of weakest strength or greatest load.

This paper presents an automated approach in three-dimensional digital model generation of human joints based on MRI and CT scans. Since both the MRI and CT scans are going to be used in the digitization process, a systematic approach had to be taken in obtaining these scans. In this approach the CT and MRI scans are mapped in order to obtain the exact geometry of human joint. Due to the poor visibility of the hard or soft tissue contours because of the type of imaging used, additional smoothing techniques had to be developed. Attachment points of the ligaments are also identified. As it is well known in design and engineering area that the boundary locations and conditions are important in correct computations of the systems response. The approach described is then applied to a human tibia-femoral joint with soft tissue. The method described in this paper is applicable to live subjects but a cadaveric knee is used here in order to allow verification of results by other means.

The Federal Aviation Administration (FAA) has established the strategic goal for System Capacity and Air Traffic Services to improve accessibility, flexibility and predictability in the aviation community in order to reduce flight times, crew resources, maintenance, and fuel costs. Free flight is a system concept that addresses this goal. However, the potential for certain human performance costs arise, such as a increases in flight crew workload, or decreases in flight crew errors as predicted by Supervisory Control Theory. An evaluation of system costs associated with transitioning to Free Flight using two First Principles modeling approach, the Man-Machine Integration Design and Analysis System (MIDAS) and the Integrated Performance Modeling Environment (IPME) will be performed. IPME is expected to show differential human performance effects in cockpit and air traffic control system performance over those predicted by Air MIDAS over 50 Monte Carlo simulation runs.

The Boeing McDonnell Douglas Human Modelling System was evaluated in two experiments. One involving fit of manikins to actaul body scans and conventional data, and the other comparing manikin reach envelopes with human data. Systematic deviations in proportions were found, such as overestimation of sitting height and underestimation of sitting depth and hip width. Reach envelopes were roughly of the correct size, but somewhat displaced, which was traced back to erroneous shift of the shoulder joint. It is concluded that proportions, shoulder joint and lack of compression of soft tissue created undesirable deviations.

This paper describes the validation of RAMSIS, a 3-D CAD human model for ergonomic vehicle evaluation at General Motors (GM). The model’s capability to correctly predict position and posture in vehicle CAD environments was tested. H- and Eye point locations between RAMSIS manikins and their human counterparts were compared. We concluded that RAMSIS has good position and posture prediction capabilities and is a useful CAD ergonomic evaluation and design tool for vehicle interiors.

This paper describes the validation of the Comfort Assessment function of RAMSIS performed at Saab Automobile AB. The purpose was to find out if the effects of a change in design on comfort can be predicted by RAMSIS. An interior mock-up of a car was used, in which seat, steering wheel, accelerator pedal, brake pedal and clutch pedal could be adjusted independently. In this mock-up 21 test subjects (10 men, 11 women) were told to adjust the steering wheel and the seat in the way that they obtained a good driving position. Pedals were fixed at a pre-defined position. The test subjects were told to judge the discomfort of the driving position on a scale from 1 to 10 with 1 meaning “not at all comfortable” and 10 meaning “very comfortable”. Then the test subjects were told to adjust the pedals and seat to improve the driving position, and asked to judge the discomfort of the new driving position. The seat, steering wheel and pedal positions were recorded for the two driving positions.

Exhaust acoustics simulation is an important part of the exhaust system process. Especially important is the trend towards a coupled approach to performance and acoustics design. The present paper describes a new simulation tool developed for such coupled simulations. This tool is based on a one-dimensional fluid dynamics solution of the flow in the engine manifolds and exhaust and intake elements. To represent the often complex geometries of mufflers, an easy-to-use graphical pre-processor is provided, with which the user builds a model representation of mufflers using a library of basic elements. A comparison made to two engines equipped with exhaust silencers, shows that the predictions give good results.

This paper explores the performance of light weight attenuators, which take a dissipative approach to sound abatement in the motor vehicle. An analytical model is used to predict the sound transmission loss and random incidence sound absorption of attenuators, absorbers and sandwich insulation systems. Then, a mathematical expression is developed which combines the dissipative and sound transmission loss performance to determine the total noise reduction provided in the vehicle. Using this equation, the performance of multi-layered attenuators is shown to be comparable to, or better than that of sandwich insulators. Finally, test results from various studies in vehicles show that significant weight savings can be realized by using these multi-layered attenuators, which take a dissipative approach to vehicle sound insulation, rather than the traditional sandwich insulation system.

A new method for evaluating the acoustical properties of porous materials is described here. To implement the procedure, a two-microphone standing wave tube was modified to include: a new sample holder; a section that accommodated a second pair of microphones downstream of the sample holder; and an approximately anechoic termination. A four-point sound pressure method was then used to estimate the two-by-two transfer matrix of the material. The transfer matrix can then be used to determine the wave number and characteristic impedance of the material. The procedure has been used to estimate the acoustical properties of two glass fiber materials.

Cavity reinforcement materials are used in the automotive industry to stiffen hollow cavities in unibody constructions. Typical areas of use include the engine rails, rocker panels, roof support or any other cavity in need of reinforcement. Use of these materials can allow for reductions in vehicle weight without sacrificing long-term durability and stiffness. Additional NVH benefits could be gained through the change in stiffness and through acting as a physical barrier to the propagation of noise, water and dust. The objective of this paper is to describe the properties of a new type of cavity reinforcing material and to identify key properties of reinforcing materials.

During numerical analysis of an exhaust system, the use of shell elements gives accurate results. However, it requires a lot of modeling and calculation time and a big computer system. In this paper, bar elements have been utilized for the numerical analysis of the exhaust system. It shows that the adoption of bar elements providing appropriate results can reduce modeling efforts and computing costs since less than 200 bar elements are enough during the numerical analysis of the exhaust system. To find the equivalent bar properties of curved pipe, the strain energy concept is utilized. The bellows of the exhaust system is simplified with modification of stiffness of bar elements. The developed model can be utilized to find possible hanger position with the analysis of vibration mode. The prediction of endurance performance is another benefit of the developed numerical model with bar elements.

Low density polyurethane foam, applied in general assembly, is being used as a replacement for rubber-based heat reactive baffles in automobile cavities to inhibit noise transmittance. Most chemically reactive urethane foam systems used in barrier applications are MDI-based (diphenylmethane diisocyanate). The use of classical MDI-based technology in assembly plants typically requires substantial levels of ventilation [1]. High capital and operating expenses associated with plant ventilation systems have hindered the growth of polyurethane technology. This paper describes benefits of using a low MDI polyurethane foam system in place of classical two-component MDI-based foam systems and conventional rubber-based heat reactive baffles. Severe industrial hygiene testing has indicated that ventilation requirements to use the low MDI foam system in assembly plants may be greatly reduced.

Sound absorption is one way to control noise in automotive passenger compartments. Fibrous or porous materials absorb sound in a cavity by dissipating energy associated with a propagating sound wave. The objective of this study was to evaluate the acoustic performance of a cotton fiber absorbing material in comparison to a new polypropylene fibrous material, called ECOSORB ®. The acoustical evaluation was done using measurements of material properties along with sound pressure level from road testing of a fully-assembled vehicle. The new polypropylene fibrous material showed significant advantages over the cotton fiber materials in material properties testing and also in-vehicle measurements. In addition to the performance benefits, the polypropylene absorber provided weight savings over the cotton fiber material.

A hardware / software package is presented that is used to determine the dynamic mechanical properties of viscoelastic materials as a function of temperature and frequency. The material properties can then be used to aid in the design of surface damping treatments for various engineering structures.

The high-frequency performance of automotive sound packages may be predicted by combining transmission loss and absorption calculations with statistical energy analysis (SEA) models. Vehicle SEA modeling therefore requires analytical tools that accurately describe the acoustic properties of layered structures such as trim panels. While widely accepted prediction models for fibrous materials exist, less work has been done on foam layers. This paper presents a numerical calculation of sound transmission through layered structures using a direct global matrix (DGM) solution. This numerical technique is used to compare several models for acoustic propagation in foams. Predictions are compared to transmission loss measurements for several panel configurations. A rigid porous model compares well with data up to 1 kHz for the foams studied, while foam elasticity appears to be important at higher frequencies.

A programmed heat-activated foam technology has recently been introduced for making baffles to seal hollow car body channels[1,2]. First, we summarize the key characteristics of the programmed foams. Some unique design features such as maximum gap to allow easy E-coat drainage, multiple section design for complex channels, allowance for passage of drainage hose and double-layered baffle are presented. Then, we examine the important design parameters affecting the acoustic performance of baffles based on the programmed foams. The insertion loss(IL) was measured for various baffles expanded in a test channel. The effects of foam expansion ratio, surface density, etc., on the acoustic performance of various single-layered and double-layered baffles are reported.

A new multifunctional material was developed to provide corrosion protection, anti-chip protection and vibration damping equal to or better than the existing materials today. This multifunctional coating, applied robotically or manually with airless spray equipment, is a one component system and provides the following characteristics: high vibration damping, low viscosity-easy to process, low shrinkage-no small molecules given off, no solvents, excellent adhesion to oily steel and electrocoat, excellent stone-chip resistance, high stiffness and low density. This paper describes the application and performance benefits of utilizing this sprayable, chip-resistance damper.

Constrained layer damping (CLD) is a well known technique to efficiently damp low frequency vibration. CLD employs a viscoelastic material sandwiched between two very stiff, typically metal, layers. While effective over essentially flat surfaces, CLD has not been applicable to cylindrical shapes. In order to damp low frequency vibration in metal pipes, users have been forced to rely on extensional layer damping, typically consisting of thick layers of extruded or molded rubbers. This paper discusses a novel product to damp cylindrical articles such as metal pipes with a constrained layer heat shrink tubing. This product utilizes a stiff heat shrinkable polymeric jacket bonded on the inside with a viscoelastic layer. When shrunk on a metal pipe or rod, a CLD system is produced. The product is typically thinner than an extensional layer damper and is more effective. It also meets the other physical and environmental requirements for a pipe covering.

In noise and vibration control, damping treatments are applied on panel surfaces to dissipate the energy of flexural vibrations. Presence of damping treatment on the surface of a panel also plays an important role in the resulting vibro-acoustic characteristics of the composite system. The focus of this study is to explore possibilities of reducing the weight of damping treatments by means of perforation without sacrificing performance. The power injection concept from Statistical Energy Analysis (SEA) is used in conjunction with Finite Element Analysis (FEA) to predict the effect of perforated unconstrained layer treatments on flat rectangular panels. Normalized radiated sound power of the treated panels are calculated to assess the effect of varying percentage of perforation on structural-acoustic coupling.