Search Results

The automotive industry has a strong need for lightweight materials capable of withstanding large mechanical loads. Advanced high-strength steels (AHSS), which have high tensile strength and formability, show great promise for automotive applications, yet if they are to be more widely used, it's important to understand their deformation behavior; this is particularly important for the development of forming limit diagrams (FLD) used in stamping processes. The goal of the present study was to determine the extent to which anisotropy introduced by the rolling direction affects the local fracture strain. Three grades of dual-phase AHSS and one high-strength low-alloy (HSL A) 50ksi grade steel were tested under plane strain conditions. Half of the samples were loaded along their rolling direction and the other half transverse to it. In order to achieve plane strain conditions, non-standard dogbone samples were loaded on a wide-grip MTS tensile test machine.

The objective of this research is to understand the crashworthiness performance of composite inserts in vehicle structure and to improve the numerical model of steel-composite combined structure for providing better prediction in the design process of composite inserts. A simplified steel-composite combined beam structure is used for three-point bending tests. Epoxy-based structural foam and 33% short glass fiber reinforced nylon composite insert are considered as composite fillers in empty sections of double hat-type steel beam structure. Four cases based on the different combination of composite materials are considered. In the series of physical three-point bending tests, the force-displacement (F-D) curves and material behaviors are investigated. The test results show that the composite insert greatly contributes to improve the crashworthiness of beam structure as well as to reduce the vehicle weight.

To date, anthropomorphic test devices (ATDs) have not been designed with consideration for human motion in far-side impacts. Previous tests with a cadaver and a BioSID dummy at the Medical College of Wisconsin confirmed that the dummy does not suitably model the human motion. To further evaluate different ATDs in far-side crashes, MAthematical DYnamic MOdeling (MADYMO) was employed. The modeling showed that the motion of a Hybrid III, BioSID, EuroSid1, EuroSID2, or SID2s did not accurately reflect the motion of a human cadaver under the same impact configurations as the cadaver test. The MADYMO human facet model was found to closely reproduce the kinematics of the cadaver test. The effect of varying console designs on occupant kinematics is presented in this paper. The human facet model appears to be a good interim tool for the evaluation of countermeasures in far-side crashes.

According to National Highway Traffic Safety Administration (NHTSA) speed-related traffic fatalities accounted for 31% of total fatalities on U.S. roadways in 2003. Traditional speed control methods suffer from significant shortcomings. Adaptation (ISA) systems hold the promise of safer roadways through improving driver compliance with speed limits. This paper describes the development of a new multi-modal speed adaptation system to be tested in the CISR car-driving simulator. The system is capable of adapting to the driver's driving style and provides appropriate warning for over speeding based on the vehicle speed, speed limit, driver individual preferences, and risk factor. A hierarchical manager module determines the warning strategy. The adequate warning strategy is specific to driving situations and individual characteristics. Modes of warnings being considered include VISUAL, and HAPTIC.

Vehicle stiffness is one of the three major factors in vehicle to vehicle compatibility in a frontal crash; the other two factors are vehicle mass and frontal geometry. Vehicle to vehicle compatibility in turn is an increasingly important topic due to the rapid change in the size and characteristics of the automotive fleet, particularly the increase of the percentage of trucks and SUVs. Due to the non-linear nature of the mechanics of vehicle structure, frontal stiffness is not a properly defined metric. This research is aimed at developing a well defined method to quantify frontal stiffness for vehicle-to-vehicle crash compatibility. The method to be developed should predict crash outcome and controlling the defined metric should improve the crash outcome. The criterion that is used to judge the aggressivity of a vehicle in this method is the amount of deformation caused to the vulnerable vehicles when crashed with the subject vehicle.

An active torque control steering system is developed and implemented in a car simulator. The simulator has a comprehensive and accurate full vehicle dynamics and road/environment models. A simple model of the driving simulator’s vehicle was developed and a PID controller, which uses the vehicle’s yaw angle, and position, was designed to control vehicle steering torque. The controller is then integrated with the driving simulator program, emulating the real world conditions. The developed system was tested in various obstacle avoidance and lane change scenarios in the car simulator, and the vehicle was able to avoid the stationary obstacles autonomously.

The SPA-10 project, sponsored by U.S. National Science Foundation, is to acquire and qualify a replacement for the retired T-28 “storm penetration” aircraft previously used to acquire meteorological data to enable understanding and modelling of mid-continent thunderstorms. The National Science Foundation selected the Fairchild A-10 (bailed from the U.S. Air Force) as the platform to be adapted to perform the storm penetration mission to altitudes of eleven kilometers, and funded Naval Postgraduate School’s Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) as prime contractor. An expert panel conducted a review of the SPA-10 project in 2014 and recommended a risk analysis addressing hazards to the aircraft and pilots, such as icing, hail, turbulence and lightning. This paper presents the results of the risk analysis performed in response to this need, including recommended mitigations.

This paper investigates the crashworthiness of structural composite components in frontal and side crash tests. In addition, the safety benefits of composites applications in future lighter vehicles are studied. The methodology of the research includes two steps: (1) developing a light-weight vehicle based on a current finite element (FE) vehicle using advanced plastics and composites, and (2) evaluating the crashworthiness of the light-weighted vehicle by frontal and side New Car Assessment Program (NCAP) test simulations. An FE model of a 2007 Chevrolet Silverado, which is a body-on-frame pickup truck, was selected as the baseline vehicle for light-weighting. By light-weighting components in the Silverado, the vehicle weight was reduced 19%. As a result, the content of plastics and composite in the light-weighted vehicle was 23.6% of the total weight of the light-weight vehicle.