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Frequency response methods are applied in developing an understanding of the influence of design parameters on the directional performance of commercial vehicle combinations employing full trailers. Transfer functions are used to describe the contributions of full trailers, trucks, and tractor-semitrailers to the rearward amplification between the lateral accelerations of the towing and last units in truck-full trailers, doubles, and triples combinations. These transfer functions show how forward velocity, distances from pintle hitches to center-of-gravity locations, and cornering coefficients influence rearward amplification.

A class of heavy truck vehicles, characterized primarily by high centers of gravity, was studied using analysis and computer simulation to identify and understand the relationship between directional and roll stability of such vehicles during steady turning maneuvers. Findings of the computer-based study suggest: (1) directional instability (yaw divergence) is possible for such vehicles during steady turning while operating at elevated speeds on horizontal road surfaces, (2) yaw divergence will lead to rollover in the absence of corrective steering action and/or reduced speed, and (3) the primary mechanism responsible for precipitating yaw divergent behavior in such vehicles is the nonlinear sensitivity of truck tire cornering stiffness to vertical load acting in combination with typical heavy truck fore/aft roll stiffness distributions. In addition, the influences of roadway superelevation and driver steering control as contributors to vehicle stabilization are examined and discussed.

The TMC/SAE Type I and Type II tests were developed jointly toy the SAE and the American Trucking Associations' Maintenance Council (TMC) with sponsorship from the Voluntary Truck and Bus Fuel Economy Program. The tests allow truck and bus operators and others to evaluate products and designs for fuel economy using a drive cycle of their own choosing. To encourage the use of this procedure and provide unbiased information to the industry, the Voluntary Program has begun a series of “New Energy Concepts Tests” to evaluate products and ideas.

Speed control concepts are devices, designs, or techniques which, when used separately or in combination, reduce a vehicle 's road speed to a more fuel-efficient level. The study encompassed five general categories of speed control: engine speed governors/power train numerical ratios, road speed governors, tachographs/trip recorders, cruise controls, and driver training and motivation programs. Although fleet operating experience has demonstrated that the proper use of speed control can save fuel and have other beneficial side effects, three factors affect the development of speed control programs: driver resistance, management commitment, and operational difficulties. While speed control programs can vary, companies with successful programs thoroughly investigate the market, train and motivate their drivers, and implement the program slowly with careful monitoring and structured tests.

The demand for improved fuel economy in both cars and trucks has emphasized the need for lighter weight components. The application of high strength steel to wheels, both rim and disc, represents a significant opportunity for the automotive industry. This paper discusses the Ranger HSLA wheel program that achieved a 9.7 lbs. per vehicle weight savings relative to a plain carbon steel wheel of the same design. It describes the Ranger wheel specifications, the material selection, the metallurgical considerations of applying HSLA to wheels, and HSLA arc and flash butt welding. The Ranger wheel design and the development of the manufacturing process is discussed, including design modifications to accommodate the lighter gage. The results demonstrate that wheels can be successfully manufactured from low sulfur 60XK HSLA steel in a conventional high volume process (stamped disc and rolled rim) to meet all wheel performance requirements and achieve a significant weight reduction.

Endurance tests are conducted on heavy duty vehicles to assure maintenance of structural integrity and acceptable levels of performance over the projected service life in the vocation for which the vehicles are intended. This paper reviews current practice in endurance testing as applied to the structural components of heavy duty vehicles, components, and systems. A brief historical perspective is given, describing how endurance testing evolved from an art, based mostly on experience and engineering judgment, to a rather sophisticated technology. A brief treatise is given on fundamentals of fatigue life prediction, followed by a discussion of the technology and methodology involved in proving ground testing, use of road simulators and cab shakers, and laboratory based tests of systems and components.

This paper presents the analytical results of two different computer simulations of the vehicle pedestrian impact; PROMETHEUS 2 and the MacLaughlin/Daniel (MACDAN) models. The results presented illustrate the simularity and differences between the two models and accuracy of both to predict the actual occurrance. Also presented is a discussion relative to the modeling techniques of obtaining data for the pedestrian. This presentation illustrates the scaling techniques and actual data obtained in order to accurately simulate the pedestrian.

This paper presents an interactive computer simulation of the pedestrian/vehicle interface. The simulation presents the results in an easy to analyze format including animation of the whole event. User requests for specific output data is available via a graphic menu. The model employs the use of the MacLaughlin/Daniel Computer Simulation developed by the National Highway Traffic Safety Administration. To illustrate the usefulness of the graphical and pictorial output, the results of a pedestrian/vehicle impact are presented.

A number of service fatigue history summarization statistics are examined for their suitability in regenerating the history in the laboratory. Evaluation criteria applied include: fatigue damage-per-level equivalence, implementation simplicity, waveform similarity, and fatigue life equivalence. The results suggest that a three-dimensional “From-To” matrix that includes sequence information about the original variable amplitude histories, is optimal for service history reconstruction.

This paper describes the operational testing of three quieted heavy-duty diesel trucks. The noise control treatments installed on the trucks included partial engine enclosures, improved exhaust systems, and 2-stage engine mounts on one of the trucks. The trucks accumulated 229,844 miles and the treatments were found to have negligible quantifiable impacts. Their operation was comparable to comparison untreated vehicles and there was no evidence of payload displacement because of the treatment weight. Predicted and observed fuel economy impacts were virtually immeasurable. Maintenance costs increased by 0.69% because of the impact of the enclosures on regular maintenance.

An extensive test program has been accomplished for commercial trucks and tracked military vehicles utilizing the Garrett GT601 gas turbine engine. The on-going program provides a development history of the GT601 truck engine as well as the installation and operating experience gained during the military mechanized infantry combat vehicle (MICV) test program. Problem areas and design improvements initiated to solve them are presented in considerable detail. Sufficient charts, graphs, and photographs are provided to clarify detailed technical material.

This paper describes a procedure using fatigue analysis methodology to interpret light truck rough road durability testing in terms of customer usage. The resulting correlation can be used in conjunction with optimization methods to provide a rough road durability procedure that insures adequate durability test objectives while decreasing the degree of over-test. The following procedure can be adopted to any durability test where the relationship between durability test severity and “customer” severity can be quantified. This method may create new durability testing procedures that result in less time and cost while improving durability test accuracy.

Diesel engines of the future will be the designer’s response to government regulation, economic restrictions and technological advances. This optimization process will demand adaptability and responsiveness to accelerating change in the business environment. Success will be determined by the degree of understanding of the various interactions.

Recently a demand for maintenance-free is increaing for mechanical components. We have already developed spherical plain bearings fitted with liners for railroad vehicles, which are now used in such places as anti-rolling equipments or longitudinal dampers in the vehicles for The New Tokaido Line. On the other hand, in construction machines or the like, development of a spherical bearing with high impact strength, resistance to high contact pressure and high resistance against muddy water is demanded. Investigations into anti-wear performance as well as creep resistance of various liner materials were made. It was found that polyimide resin with some fillers is the most superior.

Rolling bearings of standardized dimensions have proven to be reliable, long-lived structural components in all types of industry. Improved production methods and progressing knowledge in the fields of steel melting and heat treatment of rolling bearing steel resulted in a steady increase of the capacity of rolling bearings. This development is also reflected by the higher load ratings published recently. The new and advanced development of entire bearing series as well as the development of special bearings made to specifications are of equal importance. Such specially designed bearings opened up many modern and advanced fields of application, for example in space exploration and offshore technology. It can be said that, to date, the rolling bearing technology has fulfilled all requirements. In many cases the use of rolling bearings has resulted in economical overall designs and constructions.

Bearing damage mechanisms resulting from non-fatigue modes such as contamination, lack of lubrication, misalignment and improper handling are discussed. Included is also a discussion of fatigue modes of bearing damage. Tapered, cylindrical and ball bearings are incorporated into the discussion.

Since 1975 GLI Corporation has designed and supplied microprocessor based remote control systems for underground coal and hard rock mining equipment. Earth moving vehicles can use this technology as it exists today so long as the vehicle does not require more than six proportional, and 15 on/off controls.

The introduction of microcomputer technology into the industrial and consumer marketplaces has contributed to a significant growth in product efficiency, utility, reliability, and performance. Combining the intelligence of the microcomputer with the muscle of hydraulics has now greatly enhanced the creativeness of mobile equipment design. Significant strides have already been made with hydraulic excavator applications. Additional excavator advancements are in progress with a number of lattice boom and hydraulic crane developments soon to be accomplished. These current and proposed applications provide the basis for the topic of discussion.

Chromium and chromium-molybdenum carburizing steels are widely used for small- and medium- sized rolling bearings or gears, in Japan. Using a cylinder-to-ball type rolling contact fatigue rig, influence of various material factors such as chemical compositions, oxygen content, retained austenite and grain size in 1 % chromium carburizing steel was investigated. Life level of 1 % chromium steel has been increased gradually since 1968 when the test began. The increase in life level is mainly due to reduction in oxygen content by the improvement of steel-making technique. Manganese content increases the life and 1 % Cr steel with 1 % Mn has high reliable life. Prior austenite grain size does not seem to influence the rolling contact fatigue life.

A method for the analysis of a damaged bearing is described. An emphasis is placed on obtaining complete and accurate application information; conducting a thorough visual examination; making physical measurements as necessary; and conducting metallurgical tests. The method has been used for tapered roller bearings as well as a variety of other components of various steel types and processing histories.