Evaluation of the passive safety in cars adapted with steering control devices for disabled drivers

The purpose of this research is to analyse the influence of steering control devices for disabled people on passive safety. It is based on the advances made in the modelling and simulation of the driver position and in the suit verification test. The influence of these devices is studied through airbag deployment and/or its influence on driver safety. We characterise the different adaptations that are used in adapted cars that can be found mounted in vehicles in order to generate models that are verified by experimental test. A three-dimensional design software package was used to develop the model. The simulations were generated using a dynamic simulation program employing LS-DYNA finite elements. This program plots the geometry and assigns materials. The airbag is shaped, meshed and folded just as it is mounted in current vehicles. The thermodynamic model of expansion of gases is assigned, and the contact interfaces are defined. Static tests were carried out on the deployment of the airbag to contrast with and to validate the computational models and to measure the behaviour of the airbag when there are steering adaptations mounted in the vehicle. © 2011 Taylor & Francis.Masiá Vañó, J.; Eixerés Tomás, B.; Dols Ruiz, JF. (2011). Evaluation of the passive safety in cars adapted with steering control devices for disabled drivers. International Journal of Crashworthiness. 16(1):75-83. doi:10.1080/13588265.2010.514772S7583161Bedewi, N. E., Marzougui, D., & Motevalli, V. (1996). Evaluation of parameters affecting simulation of airbag deployment and interaction with occupants. International Journal of Crashworthiness, 1(4), 339-354. doi:10.1533/cras.1996.0025Chawla, A., Mukherjee, S., & Sharma, A. (2005). Development of FE meshes for folded airbags. International Journal of Crashworthiness, 10(3), 259-266. doi:10.1533/ijcr.2005.0343Cheng, Z., Rizer, A. L., & Pellettiere, J. A. (2003). Modeling and Simulation of OOP Occupant-Airbag Interaction. SAE Technical Paper Series. doi:10.4271/2003-01-0510Crandall, J. R., Bass, C. R., Pikey, W. D., Miller, H. J., Sikorski, J., & Wilkins, M. (1996). Thoracic response and injury with belt, driver side airbag, and force limited belt restraint systems. International Journal of Crashworthiness, 2(1), 119-132. doi:10.1533/cras.1997.0039Dalrymple, G. (1996). Effects of Assistive Steering Devices on Air Bag Deployment. SAE Technical Paper Series. doi:10.4271/960223Khan, M. U., & Moatamedi, M. (2008). A review of airbag test and analysis. International Journal of Crashworthiness, 13(1), 67-76. doi:10.1080/13588260701731674Khan, M. U., Moatamedi, M., Souli, M., & Zeguer, T. (2008). Multiphysics out of position airbag simulation. International Journal of Crashworthiness, 13(2), 159-166. doi:10.1080/13588260701788385Richert, J., Coutellier, D., Götz, C., & Eberle, W. (2007). Advanced smart airbags: The solution for real-life safety? International Journal of Crashworthiness, 12(2), 159-171. doi:10.1080/13588260701433461Ruff, C., Jost, T., & Eichberger, A. (2007). Simulation of an airbag deployment in out-of-position situations. Vehicle System Dynamics, 45(10), 953-967. doi:10.1080/0042311070153830

Finite Dynamic Elements and Modal Analysis

A general modal analysis scheme is derived for forced response that makes use of high accuracy modes computed by the dynamic element method. The new procedure differs from the usual modal analysis in that the modes are obtained from a power series expansion for the dynamic stiffness matrix that includes an extra dynamic correction term in addition to the static stiffness matrix and the consistent mass matrix based on static displacement. A cantilevered beam example is used to demonstrate the relative accuracies of the dynamic element and the traditional finite element methods

On the Optimal Shock Isolation of a System with One and a Half Degrees of Freedom

The limiting performance of shock isolation of a system with one and a half degrees of freedom is studied. The possibility of using a single-degree-of-freedom model for this analysis is investigated. The error of such an approximation is estimated. Numerical examples are presented

Wave Dispersion and Attenuation in Viscoelastic Split Hopkinson Pressure Bar

A viscoelastic split Hopkinson pressure bar intended for testing soft materials with low acoustic impedance is studied. Using one-dimensional linear viscoelastic wave propagation theory, the basic equations have been established for the determination of the stress—strain—strain rate relationship for the tested material. A method, based on the spectral analysis of wave motion and using measured wave signals along the split Hopkinson pressure bar, is developed for the correction of the dispersion and attenuation of viscoelastic waves. Computational simulations are performed to show the feasibility of the method

Capabilities of Helmets for Preventing Head Injuries Induced by Ballistic Impacts

The limiting performance of ballistically loaded helmets designed to reduce head injuries is studied analytically. The projectile does not penetrate the helmet. This analysis evaluates the absolute minimum of the peak displacement of the helmet shell relative to the head, provided that criteria measuring the severity of head injuries lie within prescribed limits. Rather than optimize a specific design configuration, e.g. a viscoelastic foam liner, characteristics of a time-dependent force representing the helmet liner are calculated. The formulation reduces the limiting performance analysis to an optimal control problem

Pre-Acting Control for Shock and Impact Isolation Systems

Pre-acting control in shock/impact isolation systems is studied. With pre-acting control, the isolation system begins to respond to an impact before this impact has been applied to the base. The limiting performance of the isolator with pre-acting control is investigated for a single-degree-of-freedom system subject to an instantaneous impact. The isolation performance index is defined as the maximum of the absolute value of the displacement of the object to be isolated relative to the base, provided that the magnitude of the control force transmitted to the object does not exceed a prescribed value. It is shown that there is a substantial advantage in the use of pre-acting isolators over isolators without pre-action. Particular attention is given to a pre-acting isolator based on a passive elastic element (a spring) separating the object to be protected from the base. An example illustrates the calculation of the design parameters of such an isolator

Review: Optimal Shock and Vibration Isolation

This is a review of the investigations into the field of optimum shock and vibration isolation, including the mathematical foundations of both optimal open-loop and optimal feedback isolation systems. This survey covers the literature from the initial studies to the present

Sensitivity of Occupant Response Subject to Prescribed Corridors for Impact Testing

A technology to study the sensitivity of impact responses to prescribed test conditions is presented. Motor vehicle impacts are used to illustrate the principles of this sensitivity technology. Impact conditions are regulated by specifying either a corridor for the acceleration time history or other test parameters such as velocity change, static crush distance, and pulse duration. By combining a time domain constrained optimization method and a multirigid body dynamics simulator, the upper and lower bounds of occupant responses subject to the regulated corridors were obtained. It was found that these prescribed corridors may be either so wide as to allow extreme variations in occupant response or so narrow that they are physically unrealizable in the laboratory test environment. A new corridor based on specifications for the test parameters of acceleration, velocity. crush distance, and duration for frontal vehicle impacts is given

Development of a dynamic multibody model to analyze human lower extremity impact response and injury

A dynamic multibody model of the 50th percentile male lower extremity is developed to examine internal loading plantar impact. The foot and leg, represented by five and seven rigid bodies respectively, are provided with degrees of freedom and stiffness values from cadaveric and volunteer data. Soft tissue structures, including the heel pad, ankle ligaments, and triceps surae muscles are represented with nonlinear viscoelastic elements. Validation involved subjecting the model to two different plantar impact scenarios and comparing the time histories of tibia compression. Achilles tendon tension, and ankle motion with those from the cadaveric test data. Injuries are predicted in the model by comparing force within the model elements with experimentally determined and published failure criteria for the respective structures. This model provides a tool for predicting soft tissue and hard tissue lower extremity injuries associated with a variety of foot and ankle loading environments