A 5 meter range non-planar CMUT array for Automotive Collision Avoidance

A discretized hyperbolic paraboloid geometry capacitive micromachined ultrasonic transducer (CMUT) array has been designed and fabricated for automotive collision avoidance. The array is designed to operate at 40 kHz, beamwidth of 40° with a maximum sidelobe intensity of -10dB. An SOI based fabrication technology has been used for the 5x5 array with 5 sensing surfaces along each x and y axis and 7 elevation levels. An assembly and packaging technique has been developed to realize the non-planar geometry in a PGA-68 package. A highly accurate mathematical method has been presented for analytical characterization of capacitive micromachined ultrasonic transducers (CMUTs) built with square diaphragms. The method uses a new two-dimensional polynomial function to more accurately predict the deflection curve of a multilayer square diaphragm subject to both mechanical and electrostatic pressure and a new capacitance model that takes into account the contribution of the fringing field capacitances

Investigation of an energy absorbing device for passenger safety

Energy absorption by driving an oversized plunger through a longitudinally slit shell has been studied. The characteristics obtained by conducting several runs indicate that such a system could be used for energy absorption and for limiting the force required to drive the plunger through the shell. The characteristics can be readily altered by changing the dimensions of the tube. Details of the experimental set-up have been given. Such an absorber has been adapted for mitigating injury sustained by the occupants in the interior of a colliding vehicle. Full advantage has been taken of the Ride down potential available to the occupant if he comes into contact with the interior of the vehicle before the vehicle comes to a stop. An analysis of the ride down has been made on the assumption of a suitable mathematical expression for the deceleration of the intact portion of the vehicle. A brief study of the existing restraint systems has been made and two passive restraint systems have been proposed which alleviate some of the inherent drawbacks of the existing systems. One of the systems proposed eliminates the need for a sensor currently used to trigger airbags --Abstract, page ii

Impact Biomechanics of the Human Body

The research reported on in this dissertation has been systematically developed through a series of interrelated studies and experiments. The purpose has been to understand and characterize the effects of sever impact loading on the human body that results from accidents involving automobiles, motorcycles, boats, other vehicles, pedestrians, swimmer, et cetera. Previous work in this arena had relied strongly on simulations of human body anatomy, has focused on the microscopic mechanical properties of bone and soft tissue, or has resorted to analytical modeling. Literature regarding mechanical properties of human tissue is plentiful. The experimental results in comparison among researchers are often quite variable, probably due to the complexity and diversity of the hard and soft materials that compose the human body. The majority of the research involves mechanical properties of human and animal bones and rarely is a full intact bone or specimen used for testing purposes. Instead, small cube samples are usually tested under static conditions. One reason for the widespread use of small cubes is their ease of use in material testing. The mechanical properties, however, of a full intact bone and/or intact specimen are much different than those found in a small cube section of bone or a dissected soft tissue part. This is due to the anisotropic and viscoelastic nature of these materials. When bone is combined with the various soft tissue components (muscles, tendons, ligaments, vessels, nerves, fascia, fat, skin, et cetera), a black box complex composite structure is created that needs to be characterized as a material of its own. Hence, more realistic data is needed about impact trauma effect on the human body. This research helps bridge-the-gap to this previous research through the use of various intact cadaveric specimens. The approach has been to develop a unique impact biomechanics laboratory, an air bad research laboratory, and various other testing apparatuses. In addition, existing facilities such as a drop tower, standard structural mechanical test equipment, and, in one instance, a specialized marine research facility were used when appropriate. This research focuses on macroscopic effects of impact loading and includes: comparison of embalmed versus unembalmed specimens, fracture patterns of long bones, impact response of the frontal bone and face, and response of the spine. The study also includes evaluation of the air bad as a protective device and evaluation of a particular cage guard design for boat propellers as a safety device. Reduction or prevention of impact injury through design of protective devices/safer environments requires certain biomechanical information. This includes a characterization of how the body region of interest responds to impact forces in terms of mechanical parameters such as force-time histories of impact, accelerations/decelerations, and deformations in the tissue structures. Also, mechanisms by which the tissues fail, mechanical parameters by which they respond, and the values of the injury criteria are important results in impact biomechanics research. These biomechanical behaviors and injury characterizations are the essence of the different parts of this dissertation

The assessment of older drivers' capabilities: a review of the literature

Notes: For the GM/US DOT project entitled: Improvement of Older Driver Safety Through Self-EvaluationFull Text: http://www.umtri.umich.edu/library/pdf/1998-24.pdfGeneral Motors Corporation, Warren, Mich.http://deepblue.lib.umich.edu/bitstream/2027.42/1245/2/91182.0001.001.pd

Southwest Research Institute assistance to NASA in biomedical areas of the technology utilization program

The activities are reported of the NASA Biomedical Applications Team at Southwest Research Institute between 25 August, 1972 and 15 November, 1973. The program background and methodology are discussed along with the technology applications, and biomedical community impacts

Effet d'une exposition prolongée aux vibrations sur les vertèbres lombaires des chauffeurs

L'imposition de vibrations a I'ensemble du corps humain peut etre une source d'inconfort ou de dommages pour la sante, selon I'amplitude, la frequence, la duree d'exposition, le type d'ossature, la densite osseuse, le poids corporel et la posture. La litterature fait etat de multiples causes pouvant declencher des problemes de maux de dos. De nombreuses etudes font mention que ces problemes sont constates, entre autre, parmi une population exposee, a long terme, a des charges vibratoires dans le transport (tracteurs, camions, autobus, metro, autres vehicules industriels, etc.). Il existe deux courants de pensee non exhaustifs en ce qui a trait aux maux de dos provenant possiblement des vibrations: I'hypothese que ces maux sont dus aux lesions des tissus mous (disque, muscles) et l'hypothese qu'ils sont dus aux dommages des os. La plupart des recherches experimentales ont montre que, sous un chargement dynamique compressif, les dommages apparaissent le plus souvent au niveau du corps vertebral. En effet, I'exposition du rachis lombaire aux vibrations mecaniques, notamment chez les conducteurs, sollicite la partie lombaire a la compression simple; un tel chargement minimise les lesions discales puisque differentes modelisations des effets mecaniques sur le disque intervertebral ont permis de conclure que I'hernie discale se produit principalement sous I'effet d'efforts de torsion ou d'efforts de flexion couples a des efforts d'inclinaison laterale. Les contraintes dynamiques generees peuvent etre a l'origine d'apparition et de cumul de micros-fissures dans I'os spongieux ainsi que dans les plateaux cartilagineux (conduisant au dommage par fatigue des os) et ceci malgre le potentiel de remodelage de l'os. Avec I'hypothese que les maux de dos chez les conducteurs proviennent essentiellement des dommages des os, une recherche a ete effectuee dans le but de determiner les limites d'exposition aux vibrations a long terme. Nous avons developpe deux modeles, l'un statistique et 1'autre parametrique par elements finis pour etudier les effets des vibrations sur les vertebres du rachis lombaire des conducteurs. Une analyse statistique a demontre que, du fait de Tinhomogeneite densimetrique et structurale des vertebres entre les individus et du fait que la resistance osseuse depend de la densite osseuse et de la continuite du reseau trabeculaire qui change avec I'age, on ne peut pas considerer que le comportement en fatigue des vertebres depende uniquement de I'excitation appliquee. Base sur les resultats de tests de fatigue pubhes, un modele statistique reliant la contrainte appliquee, I'age et la densite osseuse au nombre de cycles a la rupture des vertebres a ete developpe. Cette etude a justifie I'hypothese que la densite osseuse et l'age, outre la contrainte appliquee, ont un effet sur la fatigue du rachis. Aussi, ce modele a ameliore la prediction de la duree de vie des vertebres testees dont le coefficient de determination R^ a monte de 20% a 70%. Un modele parametrique par elements finis des vertebres du rachis, developpe dans le cadre de cette these, a permis, dans im premier volet, de calculer les frequences et les modes propres de I'unite vertebrale et du rachis et d'evaluer I'etat de contraintes pour différents niveaux d'accelerations, correspondant a I'excitation de la route. Dans un deuxieme volet, une etude de I'influence des parametres: posture, corpulence, densite apparente de l'os spongieux, aire des vertebres, taux d'amortissement du disque intervertebral, poids des individus et amplitude de I'acceleration du siege a la resonance des vertebres sur un facteur risque de dommage (FRD), developpe par nos soins, a ete realisee, selon la methode des plans d'experiences. L'effet de I'age a ete considere comme representant une diminution de la densite osseuse et du taux d'amortissement des disques intervertebraux. Une limite de 30%o du FRD a ete consideree comme crifique afm de considerer l'effet de fatigue a long terme. L'effet de la densite osseuse, de I'amortissement et du poids des individus a ete mis en evidence. Finalement, un modele de prediction de la duree de vie des vertebres du rachis en a resulte. Une analyse de fatigue a demontre qu'une acceleration de 2 m/s , correspondant a la limite de 30%), pouvait etre consideree comme une limite a ne pas depasser pour eviter le risque de dommage. Par ce travail, nous avons mis en evidence que le risque de fracture par fatigue peut etre observe sur les plateaux cartilagineux et sur I'os spongieux. Le modele de fatigue peut etre utilise comme un outil predictif pour calculer le risque encoum dans les vertebres lorsqu'un chauffeur est soumis a des vibrations verticales en position assise. Cependant, ce modele de fatigue n'a pu etre valide pour les basses amplitudes de vibration (fatigue par endurance) vu le manque de donnees dans la litterature sur la limite d'endurance des vertebres du rachis

Design optimization of heavy motor vehicle chassis

A vehicle chassis is one of the most vital components of an automobile. It supports various components like the vehicle body, engine, and suspension and transmission system. The purpose of heavy-duty motor vehicles (HMV) is to carry large loads, and this is often in harsh conditions. Therefore, the chassis design should withstand undesired static and dynamic loads experienced by the vehicle when in operation. Identifying and improving the properties of the chassis that affect the field performance of these vehicles is the key challenge faced by HMV designers. In this work, the chassis considered for improvement is the steel (St52E) TATA 1612 truck. The main measures identified for a compliant chassis are; satisfactory equivalent stresses, deformation, strain energy, safety factor and weight reduction. The chassis properties identified for improvement are the geometry (dimensions and cross-sections) and chassis material. In terms of geometry, different chassis member cross-sections (square, C, I and T) were studied under static loading. The above geometry studies are then adopted on a number of proposed metal matrix composite (MMC) materials. These are Graphite Al GA 7-230, P100/6061 and Al 6092/SiC/17.5P. In order to systematically improve these chassis variable properties, finite element model (FEM), modal analysis and Taguchi response surface methods (RSM) are used. Utilizing Taguchi design of experiments (DOE), the optimization design points are generated. The methods used are the central composite design (CCD), optimal space fill (OSF), Behnken-Box (B-B), Sparse Grid Initialization (SGI) and the Latin Hypercube (LH) design schemes. The I and T cross sections are found not to be compliant with acceptable industry requirements for application on HMV chassis. The Graphite Al GA 7-230 material, using the square profile, shows the lowest deformation of 78.33 mm and Al 6092/SiC/17.5p shows a maximum deformation of 694.83 mm under static loading. The optimization results show that the percentage of weight reduction obtained is 5.37% for the St52E material using the CCD scheme. By using P100/6061 Al and Al 6092/SiC/17.5P materials, the chassis weight reduction is 68.15% and 64.3% lower respectively over the standard St52E.Engineering, Science and TechnologyPh.D. (Engineering

Vibration, Control and Stability of Dynamical Systems

From Preface: This is the fourteenth time when the conference “Dynamical Systems: Theory and Applications” gathers a numerous group of outstanding scientists and engineers, who deal with widely understood problems of theoretical and applied dynamics. Organization of the conference would not have been possible without a great effort of the staff of the Department of Automation, Biomechanics and Mechatronics. The patronage over the conference has been taken by the Committee of Mechanics of the Polish Academy of Sciences and Ministry of Science and Higher Education of Poland. It is a great pleasure that our invitation has been accepted by recording in the history of our conference number of people, including good colleagues and friends as well as a large group of researchers and scientists, who decided to participate in the conference for the first time. With proud and satisfaction we welcomed over 180 persons from 31 countries all over the world. They decided to share the results of their research and many years experiences in a discipline of dynamical systems by submitting many very interesting papers. This year, the DSTA Conference Proceedings were split into three volumes entitled “Dynamical Systems” with respective subtitles: Vibration, Control and Stability of Dynamical Systems; Mathematical and Numerical Aspects of Dynamical System Analysis and Engineering Dynamics and Life Sciences. Additionally, there will be also published two volumes of Springer Proceedings in Mathematics and Statistics entitled “Dynamical Systems in Theoretical Perspective” and “Dynamical Systems in Applications”

Should we have a new engine? An automobile power systems evaluation. Volume 2: Technical reports

Alternative automotive powerplants were examined for possible introduction during the 1980-1990 time period. Technical analyses were made of the Stratified-Charge Otto, Diesel, Rankine (steam), Brayton (gas turbine), Stirling, Electric, and Hybrid powerplants as alternatives to the conventional Otto-cycle engine with its likely improvements. These alternatives were evaluated from a societal point of view in terms of energy consumption, urban air quality, cost to the consumer, materials availability, safety, and industry impact. The results show that goals for emission reduction and energy conservation for the automobile over the next 5-10 years can be met by improvements to the Otto-cycle engine and to the vehicle. This provides time for the necessary development work on the Brayton and Stirling engines, which offer the promise of eliminating the automobile as a significant source of urban air pollution, dramatically reducing fuel consumption, and being saleable at a price differential which can be recovered in fuel savings by the first owner. Specifically, the Brayton and Stirling engines require intensive component, system, and manufacturing process development at a funding level considerably higher than at present