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Technical Paper

Injury Potential with Misused Child Restraining Systems

1983-10-17
831604
Although child restraints are an increasingly common fixture in family cars, and even seatbelts are finding their way around children, both types of restraining systems are frequently not being used to their best advantage. Current restraint designs, misused in common ways, were studied using a variety of dummies under FMVSS-213 impact test conditions. Configurations addressed in this series include improperly installed child restraints', misused infant restraints, multiple children in too few belts, and a misused booster. Kinematic data from high-speed films are presented as well as appropriate load and acceleration data. Assessments of injury potential are made based on accepted criteria in combination with extensive laboratory testing and accident investigation experience. Results show that certain misuse configurations can have serious consequences for child occupants, while other variations from commonly accepted restraint practice perform reasonably well.
Technical Paper

A Split Fan Concept for a Medium Speed V/STOL

1983-10-03
831548
A split fan V/STOL concept when designed for short takeoff and landing (STOL) can have a useful load comparable to a conventional takeoff and landing (CTOL) aircraft. The STOL capability includes a deck run of no more than 400 feet, while retaining an excellent vertical takeoff and landing (VTOL) capability. This concept also offers a simple lightweight cross-duct multiengine coupling which is adaptable to either a twin or four engine configuration. The selection of number of engines will depend on the safety of flight requirements in the VTOL mode. An inherent advantage of the split flow concept is the efficient propulsion control system which employs cross duct coupling between engines. Finally, this simple compact thrust vectored split flow system has inherent features for configuring a low-observable signature aircraft.
Technical Paper

HANDLING CHARACTERISTICS OF A SIMULATED TWIN TILT NACELLE V/STOL AIRCRAFT

1983-10-03
831549
The first government-conducted piloted flight simulation of the Grumman-designed twin turbofan-powered tilt-engine V/STOL aircraft (design 698) was conducted at NASA Ames Research Center. The aircraft is discussed with an emphasis on its unique hover characteristics. These characteristics include the adverse nonminimum phase that occurs in lateral and longitudinal translation, and the large attitude control power available. Both of these features are attributes of the control vanes (a Grumman-patented concept) buried in the fan exhaust flow. The simulation used the following NASA Ames Research Center facilities: The Vertical Motion Simulator with the interchangeable cab, the Sigma 8 computer, and the Computer-Generated Image system with a four-window display.
Technical Paper

Computers in the Cockpit: But What About the Pilots?

1983-10-03
831546
Microprocessor development has now made it possible to automate many functions previously performed manually in the cockpit. While the automatic equipment is generally reliable and works well if operated properly, it may also be misused, if designers fail to properly consider human factors in their design. Misuse or underuse may result in accidents, incidents, or sub-optimal system performance. This paper discusses the general problem of human factors in cockpit automation, and reports preliminary findings from a human factors study of the operational experience of airline pilots transitioning from older DC-9 aircraft to the McDonnell-Douglas DC-9-80.
Technical Paper

Vought Ground Effects and Transition Tests of a Tandem Fan Medium Speed V/STOL Configuration

1983-10-03
831547
Vought has participated with the Navy and NASA in studies of various subsonic and supersonic V/STOL aircraft. From these studies, a unique propulsion concept, the Tandem Fan, has been developed. A. 11 scale subsonic V/STOL Tandem Fan model has recently been tested in Vought's large ground effects facility (LGEFF) and Vought's 7 × 10 ft low speed wind tunnel. The Vought large ground effects facility, provides V/STOL testing at hover in the presence of 0 to 30 knots winds in a free circulation environment. The Tandem Fan tests in this facility consisted of over 100 runs to evaluate both attitude and control effects. Individual fan thrust modulation was tested to evaluate pitch and roll control effectiveness, and exhaust nozzle perturbations were tested for yaw control. The model was then installed in the Vought 7 × 10 ft. low speed wind tunnel to evaluate the cruise and upper transition flight regions.
Technical Paper

Commercial Transport Technology Advances

1983-10-03
831556
This paper provides a perspective on commercial aircraft technology developments for the rest of the 20th century. It discusses primarily the airplane but includes observations on other parts of the transportation system. Historical achievements in commercial transport design are reviewed and form the basis for predictions of future progress in contributing aeronautical technical areas. A summary assessment of the positive aspects of current commercial aircraft development is given, along with a listing of issues, which must be considered in maintaining leadership in this field.
Technical Paper

Design of an Advanced Composite Outer Duct for the F404 Engine

1983-10-03
831550
The use of advanced composite structures in aircraft gas turbine engines is increasing as weight and cost reductions become more difficult to achieve with conventional and even quite sophisticated metal designs. The present outer duct of the F404 engine is a chemically-milled titanium part. It is the objective of the program described in this paper to reduce the weight and cost of this component through the use of advanced composite materials. Starting in 1979, under Navy and NASA sponsorship, a graphite/PMRl5 version of the F404 outer duct has been going through its design and development phases. Two complete ducts were built under this portion of the program. One duct has accumulated over 1200 hours of ground engine testing while the other duct has been successfully static tested. Based on the design, fabrication, and test effort accomplished to date, a significant cost savings and a 10% weight reduction are projected for the composite duct versus the current titanium duct.
Technical Paper

RESEARCH TECHNOLOGY NEEDS FOR TRANSPORT AIRPLANES

1983-10-03
831554
The transport aircraft industry is important to the United States' economy, but is strongly challenged by current and potential foreign competitors. Its primary technology needs are those aimed at propulsion efficiency improvements, weight reduction, drag reduction, and advanced flight systems that will reduce direct operating costs. The most promising such technologies are briefly reviewed as to their status, potential, needed efforts, and the United States Government's recent and recommended roles.
Technical Paper

Morphological and Biomechanical Study of 146 Human Skulls Used in Experimental Impacts, in Relation with the Observed Injuries

1983-10-17
831619
Biomechanical studies related to the head have been mainly directed towards the determination of cerebral tolerance to impact in the absence of fracture. However, the frequency of skull trauma producing complex fractures and cerebral lesions linked to these fractures should be taken into consideration. On a human being, impacts under similar mechanical conditons can produce either fatal encephalic lesions without fractures or skull fractures with encephalic lesions if the subject has a different skull morphology. A sample of 146 subjects has been studied to determine the relation between the morphological characteristics of the skulls (weight of the skull cap, thickness, weight of the cranial skeleton…), their mineralization. The mechanical tests were performed on bone fragments (bending and shearing tests). Nine accelerometers were used during the experiments of various types of impacts. The results were computerized. The skull fractures observed (a total of 45) are described.
Technical Paper

Head Impacts with Roof-Pillar Support Structures - Problem Identification

1983-10-17
831620
The objective of this study is to assess the safety problem concerning head impacts with roof-pillar support structures and to identify potential remedies for the problem. Also, the study presents an illustration of using accident data, in conjunction with the existing laboratory test data and mathematical simulations, as a tool for the evaluation of motor vehicle safety problems. The study starts with a general discussion on the occupant harm distribution as a function of injury sources and injured body regions, then progresses to head impact problems. The subject head impact problem can be characterized as a typical hard impact problem. Also, hard copy accindent reports were analyzed to better understand the real world head injury mechanisms that when combined with biomechanics data, were used to identify practical approaches for head injury mitigation. The study was based on the NCSS and the NASS accident data, laboratory impact test data, and occupant crash simulations.
Technical Paper

The Role of Impact Location in Reversible Cerebral Concussion

1983-10-17
831618
Mechanical impacts were delivered by an air propelled striker to the front, side, rear and top of rigid protective caps worn by six anesthetized monkeys. These tests were to produce reversible concussion and to determine differences in tolerance to concussion among the four impact sites. Striker force and cap accelerations were measures of the impact severity and animal blood pressure, respiration and ECG changes were measures of the physiological effects. By distributing the blow with a protective cap, allowing free head movement after impact, skull fracture was eliminated and simple reversible concussion could be produced without symptoms of residual neurological deficit. Higher linear and angular accelerations produced longer periods of unconsciousness (more than 3 times) on the side than at any of the other locations.
Technical Paper

Study of “Knee-Thigh-Hip” Protection Criterion

1983-10-17
831629
. A series of fresh human cadaver and Part 572 dummy tests was performed under different conditions which were comparable to those of real-world accidents. A European car model mounted on a sled was used; a pair of knee-targets was fixed directly to the car body in front of the passenger knees. Test conditions are summarized as follows: human-3-pt-belted cadaver with a sled impact velocity of 50 or 65 kph; 2-pt (thoracic)-belted-cadaver with a velocity of 65 kph, the legs being positioned normally or in an oblique manner. Since the knee-thigh-hip tolerance is related to the shape and duration of the impact pulse, these interactions were the subject of a study. The tolerance to fractures depends to a great extent on the subject's bone condition.
Technical Paper

Seated Posture of Vehicle Occupants

1983-10-17
831617
This paper describes the methodology and results from a project involving development of anthropometrically based design specifications for a family of advanced adult anthropomorphic dummies. Selection of family members and anthropometric criteria for subject sample selection were based on expected applications of the devices and on an analysis of U.S. population survey data. This resulted in collection of data for dummy sizes including a small female, a mid-sized male, and a large male. The three phases of data collection included: 1. in-vehicle measurements to determine seat track position and seating posture preferred by the subjects for use in development of laboratory seat bucks; 2. measurement of subject/seat interface contours for fabrication of an average hard seat surface for use in the buck; and 3. measurement of standard anthropometry, seated anthropometry (in the buck), and three-dimensional surface landmark coordinates using standard and photogrammetric techniques.
Technical Paper

Durability, Repeatability and Reproducibility of the NHTSA Side Impact Dummy

1983-10-17
831624
A series of seventy-two pendulum-type impact tests were performed on six NHTSA Side Impact Dummies (SID) to assess dummy repeatability and reproducibility. A quantity called the Normalized Integral Square Error (NISE) is used to quantify the difference between acceleration responses from repeat tests. Limits for the NISE are developed to define acceptable differences in terms of phase shift, amplitude, and shape. Results indicate that the SID is repeatable in all of the test cases considered and fairly reproducible in 90° lateral impacts although this is not shown conclusively. Before the testing could be performed it was necessary to correct several durability problems with the SID that were identified while early production versions of the dummy were being tested. These modifications are described briefly.
Technical Paper

Experimental Study of a Compliant Bumper System

1983-10-17
831623
An ordinary rigid bumper system and a compliant bumper system for pedestrian protection developed by the NHTSA, US Department of Transportation, were compared in an experimental study of leg injuries in car-pedestrian accidents. Human leg specimens were struck in 20 experiments with a production car front using the two bumper types. Impacts were made with an ordinary front configuration with the bumpers at the 45 cm level and a 12.5 cm lower front configuration with the bumpers at the 32.5 cm level. The impact velocity was 30-32 km/h. Serious leg injuries were noted with both front configurations and bumper types. The compliant bumper seemed to cause less serious injuries than the rigid one, and the lower front configuration seemed to cause less serious injuries than the ordinary one. A lower bumper level than today's standard and a compliant bumper type is recommended in combination to reduce the risk of serious leg injuries in car-pedestrian accidents.
Technical Paper

Biomechanical Accident Investigation Methodology Using Analytical Techniques

1983-10-17
831609
The purpose of this paper is to describe a combination of state-of-the-art detailed accident investigation procedures, computerized vehicle crash and occupant modeling, and biomechanical analysis of human injury causation into a method for obtaining enhanced biomechanical data from car crashes. Four accident cases, out of eighteen investigated, were selected for detailed reconstruction. Three were frontal impacts while the fourth was lateral. The CRASH II and MVMA 2-D analytical models were used in the reconstruction process. Occupant motions, force interactions with vehicle components, accelerations on the various body segments, and much other information was produced in the simulation process and is reported in this paper along with scene and injury data from the accidents.
Technical Paper

Biomechanics of Nonpenetrating Aortic Trauma: A Review

1983-10-17
831608
Life threatening chest injury can involve partial or full tears of the aorta. Investigations of fatal injuries in automobile accidents indicate that aortic trauma occurs in 10-20% of the cases. The major sites of aortic trauma include the aortic isthmus, the root, and the aortic insertion at the diaphragm - all of which are points of aortic tethering. The biomechanics of the injury process involve stretching of the vessel from points of tethering and hydrodynamic increases in blood pressure, which stretch the tissue to failure at a strain of about 150%. The non-isotropic stretch response of aortic tissue is discussed with reference to the frequent transverse orientation of the laceration. Congenital and pathophysiological conditions also influence the failure characteristics of the tissue. The significant factors associated with traumatic injury of the aorta are discussed in this review paper which is based on published technical information.
Technical Paper

Cervical Spine Injury Mechanisms

1983-10-17
831616
A test series using eight unembalmed cadavers was conducted to investigate factors affecting the creation of cervical spine damage from impact to the crown of the head. The crown impact was accomplished by a free-fall drop of the test subject onto a load plate. The load plate striking surface was covered with padding to vary the contact force time characteristics. The orientations of the head, cervical spine, and torso were adjusted relative to a laboratory coordinate system to investigate the effects of head and spinal configuration on the damage patterns. Load and acceleration data are presented as a function of time and as a function of frequency in the form of mechanical impedance.
Technical Paper

Experimental Spinal Trauma Studies in the Human and Monkey Cadaver

1983-10-17
831614
Compression studies were conducted on the ligamentous thoracolumbar spines of fresh human male cadavers. For comparison, forces were applied to the posterior upper thoracic region of intact seated cadavers. Since thoracolumbar flexion injury routinely involves ligament failure and vertebral body wedge compression fractures, studies were conducted on single vertebral bodies and isolated ligaments. Similar studies were conducted in isolated monkey ligaments. The intact and ligamentous thoracolumbar spines failed predominantly in the region of the thoracolumbar junction at forces from 1113-5110 N. For both the human and monkey cadavers, the anterior longitudinal ligament was the strongest. The human ligaments were 2-5 times stronger than those of the monkey.
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