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Technical Paper

“U” Bolt Torque Influence over Leaf Springs

Abstract ”U” bolts are fixing elements and they are used to clamp an elastic joint. From the past, they still looking as an old design and unfortunately, suspension engineers are not specialists in fasteners and elastic joints. That is why we will show important assumptions and concepts to design and specifications this clamp element “U” bolt and its influence over leaf-springs. Currently, “U” bolt is used to clamp an elastic or elastic-plastic joint of heavy duty suspension, formed by leaf-spring, axle, spring pad, “U” bolt plate. This kind of suspension is typically used to trucks, buses and trailers. We are wondering, which one important assumption that an engineer must be careful when designs a new suspension changing from old designs to an updated technology. We provide a theoretical analysis and a FEA analysis to compare torque efficacy x leaf-spring reactions and what are effects this relationship can cause in a suspension.
Technical Paper

“Sky Hooks” for Automobiles

IN this paper the authors present some experimental results obtained by using the analysis outlined by Prof. James J. Guest before the Institution of Automobile Engineers, in 1926. To make the experimental work more understandable, they present the essential points of Professor Guest's analysis. Professor Guest begins his analysis of the movements of a car body with the simplest set of conditions and presents a graphical as well as an algebraic solution. He then includes one additional factor after another in his analysis until the principal factors in car suspension are included. After all factors are considered, the essential structure of the simple analysis is retained. The authors' efforts at the experimental determination of the moment of inertia of passenger cars were started in January, 1932, on Sir Charles Dennistoun Burney's “tear-drop” design with which he visited leading American manufacturers.
Technical Paper


Buick engineers are well pleased with their '69 Chassis. Benefits of a unique front suspension camber curve are documented. The effects of various suspension parameters on ride and handling are explained. These were varied independently of one another in the course of evaluating over 30 suspension configurations.
Technical Paper

Xtend: a New Concept for Automatic Wear Compensation in Clutches

With the Xtend clutch a new concept for automatic wear compensation, which is suitable for push- and pull-type clutches of all sizes, has been developed. A very high level of accuracy of the adjusting process could be achieved under all operating conditions by the direct mechanical coupling to the wear of the clutch facings. It can be used without any changes to existing interfaces and possesses the same robustness and is as easy to handle as any conventional clutch.
Technical Paper

Windshield Wiper Linkage Analysis

The Kinematic Analysis Methods Computer Program that has been used by Ford Motor Co. to evaluate mechanisms for the past four years has been modified to generate performance curves for windshield wiper linkages directly using a Calcomp Plotter. Problems such as stalling, “jerky” operation, and excessive phase lag between wipers can be detected early in the design stages by careful evaluation of the curves.
Technical Paper

Wind-Tunnel Investigation of a General Aviation Airplane Equipped With a High Aspect-Ratio, Natural-Laminar-Flow Wing

An investigation has been conducted in the Langley 30- by 60-Foot Wind Tunnel to evaluate the performance and stability and control characteristics of a full-scale general aviation airplane equipped with a natural-laminar-flow wing. The study focused on the effects of natural laminar flow and boundary layer transition, and on the effects of several wing leading-edge modifications designed to improve the stall resistance of the configuration. Force and moment data were measured over wide angle-of-attack and sideslip ranges and at Reynolds numbers from 1.4 × 106 to 2.1 × 106 based on the mean aerodynamic chord. Additional measurements were made using hot-film and sublimating-chemical techniques to determine the condition of the wing boundary layer, and wool tufts were used to study the wing stalling characteristics. The investigation showed that large regions of natural laminar flow existed on the wing which would significantly enhance the cruise performance of the configuration.
Technical Paper

Which Spring? Where?

In selecting springs for commercial vehicles, it is essential to consider the fundamental principles of the suspension system as a whole, as well as the specific spring characteristics. This paper discusses the applications of these principles; also, it compares the many types of springs available, including single leaf, multileaf, and two-stage leaf springs, and coil, rubber, and pneumatic springs. Among the considerations stressed are: the relationships of spring static deflections to vehicle pitch frequency and oscillation center location, the questionability of two-stage leaf springs, the disadvantages of single tapered leaf versus multi-leaf springs, the advantages of coil springs in low weight and variable rate, and why pneumatic springs are ideal for large load range, heavy commercial vehicles.
Technical Paper

Wheel Suspension for an Advanced Flying Automobile

Abstract Principles and important parameters for design of landing gears for general aviation airplanes and suspensions for automobiles are described. A comparison between automobile, aircraft and Advanced Flying Automobile (AFA) design requirement reveals that a new generation of suspension has to be developed to gain the flexibility, efficiency and high kinetic energy absorption capability needed for an AFA suspension system. AFA design concepts and advantages were described and explained in previous SAE-papers e.g. “Design concepts and market opportunities for Flying Automobiles” and “Design Methodology and Infrastructures for Flying Automobiles”.
Technical Paper

Weight Optimized Design of a Front Suspension Component for Commercial Heavy Trucks

Design of suspension systems for Heavy Trucks is always challenging due to the heavy loads the system is exposed to and the long life requirements for the total system. Historical solutions were over designed structures to get the needed life and reliability. This always meant heavier parts. In today's economy, the vehicle weight of commercial heavy trucks is a very important feature for our customers and the end user. Lighter, well-designed suspension components provide better ride quality to the drivers through lower un-sprung weight, lower initial costs and greater payloads. The latest available structural optimization techniques are a business requirement for tomorrow's products. This paper describes the developed methodology used by DANA Engineers to design a weight optimized upper control arm for Commercial Heavy Trucks in step by step fashion. The method starts with determining the loads on the component part.
Technical Paper

Volvo 760 GLE Rear Axle Suspension

The main objective of the design has been to combine the suspension elements of a live axle in such a way that low frequency (50 - 200 Hz) engine torque fluctuations will be adequately insulated from the body and in this way diminish any tendency to body boom even when driving at low speed with a 4 cylinder car. The goal should be met without infringing upon other desirable characteristics of the rear axle suspension. The importance of wind-up compliance, and properly positioned attachment points on the rear axle housing is stressed. Results from sound and vibration measurement and computation are given.
Technical Paper

Volvo 760 GLE Multi-Link Rear Axle Suspension

Based on the property requirements for the complete car, an analysis was done of the relevant parameters for each property. These parameter values were then used for guidance when the suspension principle was selected, and later on in the design of the sub-systems, their elastokinematics, and finally in the design of the actual components. By applying the principle of one component per function, it is possible to avoid compromising between various sub-properties. The Multilink rear suspension, with its multiple degrees of freedom, follows this principle.
Technical Paper

Volute Spring Bumper System

There are numerous engineering solutions to the energy management problem in low-speed vehicle bumper impact situations. This paper covers a North American Rockwell volute spring energy storage assembly. Selection of a system involves price, performance, installation, weatherability, reliability, etc. Extensive tests-pendulum corner impact, barrier, and pendulum-were carried out and showed that the volute spring assembly on a test vehicle withstood more than 100 impacts without evidence of failure.
Technical Paper

Volume Morphing to Compensate Stamping Springback

A common occurrence in computer aided design is the need to make changes to an existing CAD model to compensate for shape changes which occur during a manufacturing process. For instance, finite element analysis of die forming or die tryout results may indicate that a stamped panel springs back after the press line operation so that the final shape is different from nominal shape. Springback may be corrected by redesigning the die face so that the stamped panel springs back to the nominal shape. When done manually, this redesign process is often time consuming and expensive. This article presents a computer program, FESHAPE, that reshapes the CAD or finite element mesh models automatically. The method is based on the technique of volume morphing pioneered by Sederberg and Parry [Sederberg 1986] and refined in [Sarraga 2004]. Volume morphing reshapes regions of surfaces or meshes by reshaping volumes containing those regions.
Journal Article

Virtual Tool to Predict Trunk Spring Movement Including Tolerance Variation

Abstract A 3D-and-Excel-based predictive tool was developed to determine trunk spring movement for preventing recurrence of a noise problem. While effective, the tool could not completely explain measured results on the completed body unit (CBU). Since design data is used as the input, it was hypothesized that the difference between predicted and actual results was related to tolerance variation on the actual vehicle. Using Siemens® Variation Analysis software, the CBU was built and simulated virtually with tolerances using a Monte Carlo model. The study found that the hypothesis was correct; tolerance variation was fully responsible for the differences. In addition, the study also allowed accurate prediction of failure rates.
Technical Paper

Virtual Simulation Research on Vehicle Ride Comfort

In this paper, a computer model of a multi-purpose vehicle (MPV) is built to study vehicle ride comfort by multi-body system dynamic theory. Virtual test rigs are developed to perform natural body frequency tests and random road input tests on the complete vehicle multi-body dynamic model. By comparing simulation results with field test results, the accuracy of the model is validated and the feasibility of virtual test rigs is established.