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SAE MOBILUS Subscription

Medical Devices and Equipment

The Medical Devices and Equipment subscription provides an extensive collection of SAE standards, technical papers, and briefs relating to the materials and processes used in the design and testing of medical devices and equipment. The more than 170 standards and 160 technical papers in this subscription focus primarily on the specialized metals and alloys needed in the competitive medical marketplace, while the 100+ articles from well-respected industry publication Medical Design Briefs give a broader overview of market issues. Sample documents in this subscription include: Automatic Shot Peening Heat Treatment of Low Alloy Steel Parts Titanium and Titanium Alloy Tubing Tolerances Corrosion Resistant Steel Wire Titanium Suspension Springs Understanding Material Properties Splitting Hairs: Measuring Thin Medical Wire

Spotlight on Design Insight: Sensors: Noise Avoidance and Cable Manufacturing

“Spotlight on Design: Insight” features an in-depth look at the latest technology breakthroughs impacting mobility. Viewers are virtually taken to labs and research centers to learn how design engineers are enhancing product performance/reliability, reducing cost, improving quality, safety or environmental impact, and achieving regulatory compliance. Extreme environment sensors require extreme environment cables that can reliably perform in temperatures up to 2300° F, withstand intense vibration, and have extraordinary strength. In the episode “Sensors: Noise Avoidance and Cable Manufacturing” (8:53), an engineer at Meggitt Sensing Systems demonstrates the intricate process of developing cable for sensors used in these situations.

New Solutions for One Shot Hand Held and Robot Drilling of CFRP/Titan and -/Aluminium Stack Drilling in H8 Quality for Aerospace Applications

This article characterizes the special features of drilling of CFRP/Titanium and -Aluminium stacks. Simplified theoretic models will show how CFRP/Titanium stacks should be machined without scratches and burn marks contacting carbon. Low axial forces and smart chip removal technology are the main characteristics of the drilling tool technology, optimized to reach H8 quality in one shot operation. Presenter Peter Mueller-Hummel, Cutting Tools Inc.

High Volume Production of Fiber Reinforced Thermoplastic Parts

With the increased demand for high volume, cost-effective, fiber-reinforced thermoplastic parts, the lack of high throughput systems has become more pronounced. Thermoforming as a method to generate complex shapes from a flat preform is dependable and fast. In order to use readily available, standard unidirectional impregnated thermoplastic tape in this process, a flat perform must be created prior to the thermoforming step. Formerly, creating the preform by hand layup was a time consuming and therefore costly, step. Fiberforge�?s patented RELAY� technology overcomes the challenges of handling thermoplastic prepreg tape and provides a solution through the automated creation of a flat preform, referred to as a Tailored Blank?. Producing a part for thermoforming with accurate ply orientation and scrap minimization is now as simple as loading a material spool followed by a pressing a start button. Presenter Christina McClard, Fiberforge
Technical Paper

Measurement of the Biodynamic Response of the Hand-Arm System and Study of its Influence on the Vibrational Response of the Steering Wheel

Driver’s hands modify the vibrational response of the steering wheel, so that car manufacturers are used to measure vibrations of the free steering wheel to ensure reproducibility. However, levels measured in this condition do not represent those perceived by the driver. The aim of this study is to predict the vibrational response of the hand-wheel coupled system from measurements of the non-held steering wheel, and of the mechanical impedance of the arm. The mechanical impedance of the hand-arm system is measured at three levels of vibration (0.5 2.5 and 5 m/s²) in two directions of excitation (along the arm and in the normal direction of the palm). The position of the arm and the hand grip are controlled to be as close as possible to a driving situation. For each condition, the mechanical impedance is calculated and compared to models of ISO 10068.

Head Injury Biomechanics, Set

Nearly 50,000 Americans die from brain injuries annually, with approximately half of all Traumatic Brain Injuries (TBI) being transportation-related. TBI is a critical and ever-evolving safety topic, with equally important components of injury prevention, consequences, and treatment. This 3-volume set presents a comprehensive look at recent head injury research. Editor Jeffrey A. Pike has selected the most relevant technical papers spanning the early 1990s through the beginning of 2011, including several older papers which provide an essential historical perspective. Each volume in the series also includes a table of references arranged by topic and a new chapter tying together anatomy, injury, and injury mechanism topics. Buy this Set and Save! The three-volume set consists of these individual volumes: Head Injury Biomechanics, Volume 1--The Skull Head Injury Biomechanics, Volume 2--The Brain Head Injury Biomechanics, Volume 3--Mitigation
Technical Paper

Automobile Bodies, from the Abstract Customer's Viewpoint

CONSTRUCTIVE criticism of automobile bodies as now built is given herein, based on experience gained in driving five-passenger sedan cars of many makes a total distance of nearly 10,000,000 miles in one year in tests at the General Motors Proving Ground. The fault finding, although humorously exaggerated, will be valuable if taken seriously, as it gives to all body designers and builders the benefit of testing experience that few companies are in a position to gain at first hand. The author treats his subject from the viewpoint of the abstract customer; that is, the automobile-purchasing public as a whole and as represened by the imaginary average man, who is assumed to have average stature and body structure and to drive all the different makes of car. Thus he is assumed to change from one to another make frequently, instead of becoming used to only one or two cars.
Technical Paper

Measurement of Comfort in Automobile Riding

EXPERIMENTS that have been in progress since the 1929 Semi-Annual Meeting to measure the fatigue caused by an automobile ride, using the human body as a measuring instrument, and to predict there-from the possible effects of various types of spring-suspension, shock-absorber and other comfort-giving components are described. Initially, the problem was approached from the physiological standpoint because fatigue is definitely known to be a physiological phenomenon and, if the physiological changes are sufficiently marked to be measured, physiological tests are definite and quantitative. Changes in the human body are a good index of relative comfort, and, if the normal reactions of an individual or any group of individuals before a test are known, similar measurements at the end of a test or at the end of an automobile ride should show an appreciable difference.
Technical Paper

Practical Experiences with Devices for Damping Torsional Vibrations

EARLY troubles experienced with torsional vibration in the shafting of marine and Diesel engines are mentioned, following which the various types of torsional-vibration damper are listed. Comments on the different ones are presented with particular reference to a damper with hydraulic coupling for a 3000-hp. 10-cylinder Diesel engine. The operation of this damper is described at some length, the text being supplemented by illustrations. Results of tests with this device are presented graphically, and the conclusion is drawn that the damping flywheel with hydrostatic coupling permits (a) damping of vibration of shafting even when running in the most dangerous speed-ranges of the largest engines and (b) running at all speeds without regard to vibration and without resorting to hand operation of the damping device.
Technical Paper

Weight Saving by Structural Efficiency

METHODS employed by the author to reduce the weight of the structural frame without sacrificing strength are described in the paper. To obtain this result the best available cross-section must be selected and the members arranged to transmit the load directly to the final supports which should lie approximately in a plane that is parallel to the load vector; also where a bending moment is caused by the loading, the support attachment should produce a moment of the same amount and of opposite sign. Avoiding secondary bending and utilizing the advantages of full continuity over supports can be secured by a simple arrangement of the frame members. Substitution of power tools for hand tools will effect a reduction in assembly costs. Sections suitable for power assembly include closed hollow-sections, which have a high structural efficiency, as well as angles, channels, I-beams and similar shapes.
Technical Paper


Although the proper timing of the spark is as essential as the spark itself and the electrical and mechanical devices for producing the spark have been many, little attention has been given to the study of spark-advance. An error in timing of ± 20 deg. in a low-compression engine, or of ± 15 deg. in most other engines, has been shown experimentally to cause a loss of 10 per cent from the best power and economy, provided other conditions remained the same. Hand or semi-automatic control can average hardly closer than ± 15 deg. to the correct advance because the speed and the load combinations are constantly changing on the road. Two important phases mark the spark-advance problem.
Technical Paper


In an endeavor to find an engineering justification for the use of the airbrake on automotive vehicles, an investigation was first made as to what actually causes a car to stop when the brakes are applied; and it was ascertained that nothing that can take place within the car itself can directly influence the motion of the automobile as a unit, that its motion can be changed only by some force external to the car itself. Four such forces are normally present, namely, wind resistance, road resistence, gravity, and the adhesion of the road to the wheels. The first two are negligible. Grades have a measurable effect on the stopping distance, but the force that actually stops the car is the last named: the force that is applied from a point external to and in a direction opposite to that of the motion of the automobile.
Technical Paper


Relative ease or difficulty of steering has in the past been largely a matter of psychology, of comparison rather than of measurement. One driver may find a car difficult to steer that another finds easy. Safety is the first essential, then comfort. Because the parts used in steering seldom break, present practice is considered safe, but the steering-ratio is very important. A low ratio that produces fast steering-effects may be entirely safe in the hands of a strong, safe, experienced driver, but absolutely unsafe in those of a weaker driver, even though he may be expert. Fatigue, however, will eventually affect the strong as well as the weak driver, so that comfort enters as well as safety.
Technical Paper


This paper is confined to a discussion of machine-shop operations, and is intended to indicate by a few examples certain important economies that might be introduced in the shops of the automotive industry. It deals chiefly with the economies that can be effected without much capital outlay, though others are also mentioned. Calling attention particularly to the fact that, in the past, improvements of methods and of equipment have been confined largely to the more important operations on the more important parts and that relatively little study has been made of the smaller pieces and the less important operations, emphasis is placed on the necessity for carefully determining which tools and which makes of tool will best serve the purposes for which they are intended and for carefully sharpening the tools and providing means of setting them accurately.
Technical Paper


Public thoroughfares have invariably been laid out to meet the requirements of age-old horse-and-buggy equipment and little thought has been given to the needs of the future. Until the middle of the last century, man was dependent for transportation upon his own strength or upon that of the animals that he could domesticate. Caesar could have traveled from Rome to Paris as quickly as could Napoleon 17 centuries later. Now, the humblest American farmer could make the round-trip with his whole family in less time than either emperor could travel one way. Within the last century have been developed in rapid succession the railroad train, the steamship, the electric trolley-car, the automobile, the motor truck, the tractor and the airplane. The most permanent thing we have is land; the very slowness and regularity with which buildings are replaced tend to make a route and the width in which it is established almost as permanent as the land of which it is a part.
Technical Paper


Always prominent in the thoughts of automotive engineers, the lubrication of an internal-combustion engine presents continuous interest in that characteristic and elusive lubrication difficulties exist which largely baffle correction. Many of these difficulties are still existent because, according to the authors, more energy has been expended in correcting diseases of the lubricating system than has been spent in preventing the diseases by original design. When analysis is made of what has been done in the last few years of study on lubrication, it is irksome to realize that we still have to contend with all the former troubles such as oil-pumping or over-lubrication, fuel dilution of the oil supply, lubrication failures under certain conditions of engine operation, excessive wear on engine parts, and high maintenance-costs.
Technical Paper


The efficiency of the automobile engine, as operated on the Otto cycle, is thought by the author to be too low, and he therefore suggests a method of improving it. He considers the various losses by which heat is dissipated in internal-combustion engines and finds that the best opportunity for increasing thermal efficiency is by an increased expansion of the charge. The author suggests that this expansion be carried 50 per cent further than is ordinarily done. In order to obtain higher efficiency at part load, the suggestion is made that instead of throttling the mixture, the admission valves be closed earlier. In case the expansion is 50 per cent longer than the induction stroke and the cut-off takes place earlier as the load becomes lighter, it will be necessary to vary the fuel opening inversely with the air induced. It is suggested that the fuel valve and cut-off lever be connected together and operated by the accelerator pedal or hand lever on the steering wheel.
Technical Paper


The author points out the diversity of opinion on what constitutes desirable car performance in the minds of engineers and of the public generally. He believes this is largely due to the great diversity of claims which have been made in advertising literature and decries the sort of tests which have been made the basis of this publicity, pointing out that a majority of them are conducted under such conditions as make it practically impossible for the car owner ever to duplicate or confirm them. The kind of an expression or test which will inform the buying public most is one which will tell what the car will do in the hands of the average owner, and define the conditions under which a demonstration of this ability can be made, such conditions to be relatively simple and easy of fulfillment.
Technical Paper

Continuation of the 1922 Report on Brake-Lining Tests1

A REPORT on the investigation of brake-lining materials by the Bureau of Standards was made by the author in 1922. The present paper gives information on work done in this field since that time. It places on record a summary and discussion of various test-methods and equipment at present employed by brake-lining manufacturers and others in the automotive industry. The difficulties connected with this work, resulting from the varying characteristics of brake-lining materials, are brought out. It is shown that some of the test methods in use do not furnish a basis for ready or fair comparison of different brake-linings. Other test procedures are so limited as to give only an incomplete picture of the characteristics of the brake-linings under conditions met in service; therefore, the test schedules generally require readjustment and amplification because a full and satisfactory knowledge of these materials can be obtained in this manner only.
Technical Paper

Development of the Silent Timing-Gear

ACCORDING to the author, gear clatter and clash caused by metal-to-metal contact develops into an annoying whir or howl at high gear-speeds, and a material was sought that is flexible and resilient enough to absorb the vibrations or change their frequency to a pitch inaudible to the average human ear. Since vibrations in the crank, the cam and the generator shafts are transmitted to the timing-gears, which run at high speeds, a material was needed that would silence the consequent noise and provide a noiseless timing-gear train. A great variety of materials was investigated and the development of laminated, phenolic, condensation products resulted; these have proved mainly suitable for timing-gear-blank stock and stock for other gears such as those suitable for crankshafts and generator shafts. A further development was that of the flexible-web cam-gear made of the composition material.