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Several polymeric materials were developed and evaluated for possible inclusion in the neck structure of state-of-the-art anthropomorphic dummies. These included three types of foam-polyvinylchloride, polyethylene, and polyurethane, and two flexible polymers-polyurethane and a polyvinylchloride chlorinated polyethylene blend (PVC-CPE). Two materials, the polyurethane elastomer and the PVC-CPE blend, were found to be satisfactory in their dynamic response. Because of the ease of casting, the polyurethane material will be used in the GMR 1 state-of-the-art dummy.

During development of the General Motors rotary engine, the lubricant was recognized as important to its success because certain lubricants produced deposits which tended to stick both side and apex seals. Consequently, it was decided to develop a rotary engine-dynamometer test, using a Mazda engine, which could be used for lubricant evaluation. In an investigation using an SE engine oil with which there was rotary engine experience, engine operating variables and engine modifications were studied until the greatest amount of deposits were obtained in 100 h of testing. The most significant engine modifications were: omission of inner side seals, plugging of half the rotor bearing holes, pinning of oil seals, grinding of end and intermediate housings, and using a separate oil reservoir for the metering pump. Using this 100 h test procedure, three engine oils and five automatic transmission fluids were evaluated.

To compute the tearing energy of nicked rubber strips in extension, one has to solve first the associated stress-deformation involving finite elasticity. In the past, this was a formidable task so that the tearing energy had been determined solely by experiments and only for a few testpieces. With the aid of the finite element method (FEM), it is shown that this may now be done simply through the use of the Rice's J integral. Tearing energy for two testpieces are computed and results compared with existing experimental data. The agreement is good. Because of FEM's ability to treat general geometric and loading conditions, the use of the J integral in combination with FEM to cmpute the tearing energy now allows a wider application of the tearing energy concept to more complex units than hitherto known.

This paper evaluates the tendency of lip seals to fracture in a test apparatus in which dynamic runout is 0.010 in and the temperature is cycled between -30 and 0 F. Seals made of eight different polyacrylate polymers were soap-sulfur cured with various types and amounts of carbon black. Physical tests included room-temperature flexibility defined by Young's modulus at small strains, standard tensile tests at room temperature, flexibility at sub-zero temperatures determined by a Gehman test, and sub-zero starting torques of the seals. Primary determinant of successful fracture resistance is a low starting torque resulting from good low-temperature flexibility. The effect of adding graphite to some of these formulations is described and some current commercially available seals are evaluated.

This paper summarizes an analysis, design, and test project in which a dummy chest structure was developed. The chest consisted of mechanical elements that had been characterized by computer simulations as giving responses to blunt frontal impacts necessary for biofidelity. An analysis of mechanical rib structures indicated that materials having a high ratio of yield stress to modulus of elasticity were required. Only metals having unusually high yield strengths, such as spring steels, qualified. A mechanical system was developed with steel ribs pivoted at each end as a primary spring. A secondary spring was a pair of commercially available die springs acting in parallel with the ribs after 25.4 mm (1.00 in) deflection. A fluid damper was developed to provide the damping. The chest structure was tested under conditions modified from those used by Kroell. The modifications were holding the spine rigidly and reducing the impact masses.

This study explores the application of viscoelastic modeling for characterization of the response of the brain to impulsive loading with the objective of learning whether such models could exhibit the same time dependency of strain or likelihood of injury, as exhibited by the Severity Index, HIC Index, Wayne Tolerance Curve, and other similar representations of tolerance. The mathematical relationships between viscoelastic properties and the corresponding time dependency of tolerance are shown for Newtonian, Bingham plastic, and Pseudo-Bingham, as well as more general behavior. Preliminary static and dynamic tests upon small mammalian material are described with particular attention given to strain in the vicinity of the brainstem as a function of loading profile. Both the theoretical and experimental results show that the falling time dependency of the above indexes can be interpreted in terms of nonlinear viscoelastic response.

Tests were conducted using older model cars with automatic transmissions to determine the effect of fluid composition on leakage past the rotating shaft seals. It was found that seal leakage was reduced or stopped by changing to seal-swelling fluids, and increased with seal-shrinking fluids. Leakage was also reduced by adding aromatic additives to existing fluids in the transmissions. Seal volume and hardness change results from bench tests support the car data.

The Total Immersion Test (ASTM D 471) for seal elastomers, used in evaluating the compatibility of fluids and seals for automatic transmissions, does not, produce hardness and volume change results similar to those found for rotating shaft seals in service. The Tip Cycle Test was devised to provide better agreement with service results. In the test, one side of the seal is exposed to air, and the other alternately to fluid and to air-fluid vapor. Rotating shaft seals were evaluated in both car and dynamometer transmission tests, and in various bench tests. Agreement was poor between transmission tests and both the Total Immersion and the Dip Cycle Tests. Good agreement was found with the Tip Cycle Test.

Effective performance of functional automotive components requires fluid sealing under compatible conditions. One method of determining this compatibility is through the use of immersion testing under a variety of conditions that simulate those experienced in actual use. By measuring the changes in the physical properties of the seal materials after immersion a judgment can be made regarding seal/fluid compatibility which will be encountered later in actual use. A series of immersion tests using representative seal materials and automotive fluids; namely, gear oils, transmission fluids, and motor oils were conducted within the framework of the Technical Committee on Automotive Rubber, jointly sponsored by SAE-ASTM.

Conventional radial lip oil seals can be made more effective by utilizing helical grooving beneath the contact lip surface. Miniature hydrodynamic pumps so formed aid the radial lip seal in containing the oil by generating fluid forces opposite in direction to the leakage flow forces. This seal-shaft combination has been termed the Hydroseal. Four factorial experiments were conducted to evaluate the effect of helix angle, groove depth, groove width, and number of grooves on sealing performance. The criterion used as a basis for selecting the optimum design were leakage, wear, hardening of the sealing surface, and pumping capacity. These data indicated that the best hydroseal design was one with three grooves, 0.0003 in. deep, 0.014 in. wide, having a helix angle of 45 deg.

The Sealometer is used for evaluating the performance of lip type oil seals and provides a dimensionless number derived from measuring the increase in temperature of a test shaft operating in a lip seal for a given time interval. With the Sealometer it is possible to study parameters that affect seal performance. As a quality control instrument, the machine provides accurate data for design. Sealometer evaluation offers a quick method of determining the life expectancy of a particular design for a particular application and eliminates the need for long life test programs.

Tire nonuniformities are a major source of vibration problems in vehicles. There is considerable disagreement on which tire uniformity parameters are important to vehicle noise and vibration problems, and on how these uniformity parameters should be measured. This paper is concerned primarily with the effects of the nonuniformities of the tire structure which cause contact patch force variations as the tire is rolled in a straight line at constant axle height. Experimental results showing the effects of mean radial load and roll size on these structural, or static, nonuniformities are presented which indicate that these force variations should be measured on a large roll at rated load. Mathematical analyses of certain vehicle vibrations show that radial and lateral force variation are important uniformity parameters. The amplitude of the first harmonic of these force variations contributes to vehicle shake.

The primary forces and moments which affect the directional control properties of wheeled vehicles are those between the road and the rolling tire. These forces and moments are nonlinear functions of a large number of parameters including slip angle, camber angle, vertical load, tire-road friction coefficient, and traction forces, among others. A new apparatus particularly suited to the measurement of the steady state tire properties most significant in handling studies is described. The forces and moments of interest are defined and typical results fora7.60-15 tire are presented to illustrate the effects of slip angle, camber angle, vertical load, inflation pressure, and wheel torque on lateral force and aligning torque.

A brief review of the testing of automatic transmission fluid for compatibility with seals is presented. The total immersion test used in fluid qualification, while apparently effective in predicting the compatibility of fluids and seals in service, does not correlate well with transmission tests with respect to hardness change of piston seals. The Dip-Cycle Test, developed to overcome this limitation, is a procedure for alternately immersing seal specimens in the test fluid and suspending them in the hot air-fluid vapor atmosphere above the fluid. Correlation of the Dip-Cycle Test with transmission piston seal results is much improved over that with the total immersion test. It is the purpose of this paper to review these developments and to present an improved test procedure (dip cycle test) for evaluating the effect of fluids on transmission piston seal materials.

A laboratory test method has been devised to measure the variation in coefficient of friction values of a brake lining as it passes through the various degrees of wetness. The results of tests on two linings are shown: the first one of the most sensitive lining material tested to date; the second an improved material.

EXTENSIVE TESTING by GM Research Laboratories has screened five promising transaxle fluids out of 32 mineral-oil-base fluids, 10 synthetic-base fluids, and numerous additive-base stock combination fluids. This paper discusses the findings of the testing and the continuing program on the five fluids. Transaxle fluids have a number of properties affecting performance, including: High-temperature viscosity. Low-temperature fluidity. Shear resistance. Friction properties. Oxidation resistance. Antifoam quality. Effect on seals. Fluid-clutch plate compatibility. Antiwear quality. Extreme-pressure quality. Antirust and anticorrosion qualities.*

THIS REPORT deals with the major parameters of a seal application which affect its efficiency and life, as determined by controlled laboratory testing in CM Research Laboratories.* A. Shaft 1. Surface Roughness 2. Machining Lead B. Assembly C. Seal 1. Seal Diameter Control Trim Interference Spring Rate 2. Seal Lip Pressure Trim Interference Spring Rate Rubber Hardness Eccentricity 3. Seal Eccentricity Mold Register Assembly Trim