Vehicles, crashworthiness

We can classify vehicle crashworthiness analysis into two categories vehicle structural analysis, and occupant injury analysis. The structural analysis studies how the vehicle structure absorbs the energy of the crash to bring the vehicle from motion to rest. The result of the structural analysis is an acceleration history of the occupant compartment. Contrariwise occupant injury analysis quantifies how the occupant interacts with the restraint system when exposed to specified acceleration history. Then the acceleration history (the crash pulse) coimects the structural analysis to the occupant injmy analysis. 

Crashworthiness and integrity of passenger compartments permit race car drivers to survive crashes at very high speeds. Special restraint features in race cars, including helmet restraints that protect the neck, have added to race driver safety. Many of the features tested in racing vehicles find their way into commercial vehicles. Crashworthiness has improved in most cars over the years. Improved design features have contributed to the reduction in crash injuries and occupant deaths. 

Newstead, S, Cameron, MH Le, CM (2000) Vehicle Crashworthiness and Agressivity Ratings and Crashworthiness by Year of Vehicle Manufacture Victoria and NSW Crashes During 1987-98, Queensland Crashes During 1991-98. Monash University Accident Research Centre, Report No. 171, Melbourne. 

Witteman WJ. Improved vehicle crashworthiness design by control of the energy absorption for different collision situations. Eindhoven Eindhoven University of Technology 1999. 

The sensitivity analysis and optimization techniques are used in many fields of engineering, but very little work as been applied directly to the vehicle crashworthiness design. However, some studies are reported in the literature where optimization techniques have been applied in crashworthiness design using simplified lumped mass models [3-5]. 

Considering the candidate materials for vehicle crashworthiness, pristine and 5 wt% GB-modilied laminates showed better absorbed energy and a minimum peak reaction force, which would improve occupant safety in the event of a vehicle crash. However, with further comparison between pristine and 5 wt% GB-modified laminates, the 5 wt% GB-modified laminates showed minimum intrusion and less strain sensitivity, which suggests that such laminates/composites are the best candidates for low-velocity impact applications. 

From a vehicle crashworthiness point of view, pristine and 1 wt% GB showed the highest absorbed energy and minimum peak reaction force, which would improve occupant safety in the event of a vehicle crash. 

The remainder of this book will examine the traffic safety policy of the last twenty years, evaluating especially the contribution of federal standards for vehicle crashworthiness—the new approach which regulates the design and construction of automobiles. 

Peltzman s pessimistic conclusion is explained by his finding two divergent effects of vehicle safety standards—a reduction in the occupant fatality rate and an increase in the fatality rate of those other than occupants of regulated vehicles—non-occupants. Peltzman finds that the occupant fatality rate is lower than projected for the regulatory period. Vehicle crashworthiness increased. However, the nonoccupant fatality rate is substantially higher than projected, and the increase in nonoccupant fatalities more than offsets the decrease in occupant fatalities. For 1972 the occupant fatality rate is 7 percent lower than the projected rate, but it is not as much lower (20 percent) as a technological approach would predict. For 1972 the nonoccupant fatality rate is 43 percent hiWr than projected and the total fatality rate is 5 percent higher than projected. ... 

Composite vehicle structural crashworthiness — A status of design methodology and numerical simulation techniques by C.M. Kindervater, D. Kohlgriiber, and A.F. Johnson, Int. J. Crashworthiness, 4, 213—230, 1999. 

The wavelets proposed by (Cemd Finek 2008 Cema Finek 2009) constitutes a successful application of filtering and smoothing for crash pulse extraction especially in the cases when pulse signatures become submerged by the noise and vibrations. The extracted pulse is described with only a few wavelet coefficients. The resulting simplified representation of a crash signal can be used in assessing the crashworthiness of the vehicle structure and also as an input to occupant injury models. 

Huston, R. L. 2008. Vehicle/occupant movement in moderate speed in-line collisions. International Journal of Crashworthiness J3(l), 41 8. 

Index of national crashworthiness (vehicle crash performance) Low Acceptable Objective... 

The vehicle safety dimension is currently based on the percentage of the vehicles (not motorcycles) in the total vehicle fleet. Additional indicators that may be added in the long term include percentage of vehicles by age of car, and index of national crashworthiness (percentage of vehicles by crash performance and the protection give to... 

Crashworthiness refers to the ability of a vehicle to withstand an accident without intrusion of or reduction in the integrity of the passenger compartment. When a crash occurs, not only is it important to minimize the second crash, it is also important to ensure that the passenger compartment stays closed and retains its shape. The idea is to keep occupants inside a protected zone during a crash. Passengers thrown from a vehicle face a high risk of injury and death compared to those who stay inside. 

Table 15.2 shows that the optimum design based on crashworthiness requirements alone reduces the overall vehicle stifBness as indicated by the frequency reduction of 6.4 % in the first mode, 5.7 % in second mode and 3.9 % in third mode. Frequencies of the current optimised design are the same as those in the baseline design. Out of 15 DV in the crash-vibration vehicle optimum, nine have increased and six have decreased relative to the respective baseline values with design variable five reaching its lower bound. 

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