J. Cuartero

Advances in the Crash Simulation of Vehicle Frontal Crash Structures Made of Braided Composite Materials

In this paper, new advances in simulation of composite materials under crash loads are applied to the analysis of a car frontal crash structure. Experimental results are used to calibrate constitutive material models and simulation procedures to obtain more accurate representation of material behavior under crash loading. These advanced computational techniques are then applied to crash simulations of components. The front longitudinal beam studied herein is analyzed for 2 load cases: frontal and lateral crash. Qualitative results on specific energy absorption, as well as the absolute energy absorbed by the structure, are especially relevant. Results of simulations of the structure in carbon and glass fibers are presented and compared, focusing on the absolute energy absorbed and specific energy absorption of the structure.

Enhanced Impact Energy Absorption Characteristics of Sandwich Composites through Tufting

Sandwich structures are highly demanded where a high flexural stiffness per weight ratio is needed. The main limiting factor of these materials is the core/skin interface, which tends to delaminate. Tufting is one of the most promising technologies to reinforce this interface along the z-direction. In this article, the energy absorption of tufted sandwich structures under impact loads is evaluated. Six different types of tufted specimens were tested, including both carbon and glass fiber faces with three different tufting densities. The impact behavior of a sandwich panel is proved to be effectively improved by the tufting process.

New Concept of Rollover Resistant Semitrailer for Hydrogen Transport

In this paper a new concept of semitrailer for hydrogen carriers is presented. It has been developed by means of numerical calculations carried out with the finite elements method. This new design of semitrailer incorporates several new functions. The first one is to achieve a rollover resistant vehicle. It has to be taken into account the absence of a specific regulation in Europe for this type of vehicles, so former vehicles were not enough rollover resistant. Nevertheless, in this development process it has been taken into account the European rollover regulation concerning large passenger vehicles “Regulation n° 66 of Geneva”, applied in this case to a vehicle having a much higher mass and a higher centre of gravity than a bus. Therefore a higher kinetic energy will be obtained in case of rollover. The second characteristic inherent to this new design of semitrailer is its lightness. It has achieved a mass reduction of 8500 kg in comparison with former designs, by means of lightening the structure, in charge of supporting the hydrogen cylinders, as well as making lighter these hydrogen cylinders themselves. Numerical models developed have been calculated by explicit integration of the dynamic balance equation. Very complex finite element models have been developed in order to include all geometric details. In these models, the elastic-plastic curves of involved materials have been included as well as its variation due to the strain rate influence. There have also been taken into account non-linear effects from contacts and from large strains that take place.Copyright

A micromechanical composite approach for finite element crashworthiness simulation

ABSTRACT The present article deals with micromechanical composite modeling. Both analytical and computational micromechanics approaches are described as well as micromechanical modeling of damage. Based on micromechanics of failure theory, a user subroutine including a progressive damage algorithm is programmed for finite element analysis. Three theory-experiment correlations of tubes under a three-point bending test have been carried out using the bi-phase material model developed along with this project. These studies include three-ply schedules.

Numerical—experimental analysis of two floor platform designs for auxiliary construction truck

In an auxiliary construction truck, the permanent deformations created by impact of rocks against the floor platform during the daily work generate the premature failure and need for replacement of the platform floor. This article shows the process followed in the analysis of two floor platforms for auxiliary construction trucks. This analysis has been carried out by means of the methodology developed in collaboration with truck manufacturer (ZAMARBU S.L) and the research group “New Technologies Applied on Vehicles and Road Safety” (VEHIVIAL) of the University of Zaragoza. The methodology applied in the floor platform development has been based on the application of numerical techniques by means of the finite element method (FEM) with explicit integration of dynamic equilibrium equation and the validation of the numerical results by means of experimental test. Applied load cases correspond to the impact of a sphere of 50, 150, and 250 kg. These load cases reproduce the impact caused by stones falling on the floor platform, which are the most restrictive for the floor design, because the vehicle’s rigidity and resistance against torsion and bending are provided for the chassis. The results of the analysis served to demonstrate the efficiency of the methodology developed for the optimization of the floor platform for auxiliary construction truck, getting an innovative floor platform design that improves the current models.

Biomechanical Response and Behavior of Users under Emergency Buffer Crash

This paper aims to study the biomechanical effects on elevator users and the injuries sustained should an elevator crash happen. The analysis will focus on buffer impact, signaling that the earlier mentioned buffer is usually located at the bottom of the pit. In order to carry out this analysis, a numerical technique based on finite element method will be used, while elevator users will be simulated by means of automotive dummies. Two crash factors will be studied, namely, location of dummy and fall velocity. The analysis criteria will be damages sustained by the dummy, based on biomechanical index such as HIC, CSI, forces, and accelerations.

Metallic Front Beam Design

In this paper, new advances in simulation of car frontal crash structure are presented. Experimental results have been used to calibrate constitutive material models and simulation procedures to obtain more accurate representation of material behavior under crash loading. These advanced computational techniques are then applied to the crash simulations of components. The front longitudinal beam studied in this paper is analyzed for frontal crash. Qualitative results on specific energy absorption, as well as the absolute energy absorbed by the structure, are especially relevant. Three designs are then proposed as potential solutions for the front side rail design. Through simulation of their impact into a wall the designs are compared on the basis of crush force and specific energy absorption and a preferred design is chosen.© 2007 ASME

Design of a Light Semi-Trailer Rear Bumper for Impact Protection According to 79/490/CEE Directive

In this paper, a new concept of rear bumper for semi trailer has been developed by means of numerical simulation. A semi trailer bumper is a substructure that has a great importance in the whole vehicle. It reduces the effect of a crash impact against another vehicle in the rear part of the semi trailer. Thus, both the vehicle and passengers are protected from impact effects. The design of this kind of structures must show suitable behavior depending upon crash conditions and structure conditions (bumper material, load cases, boundary conditions, impact velocity[[ellipsis]]). In this study case, 79/490/CEE Directive shows the specific conditions that must be complied by a rear protective device to be approved by an official certifying body. The bumper design has been carried out by means of numerical simulation tools based on the Finite Element Method (FEM). This method provides results in terms of strain and stress of the analyzed structures, subjected to several load cases, boundary conditions, and considering several materials. A new light aluminum bumper structure fulfilling the previous directive is obtained. Finally, a light bumper prototype has been developed based on the previous numerical results and it has been tested according to the homologation conditions specified in 79/490/CEE Directive. Nowadays, Lecitrailer S.A., a Spanish semi trailers manufacturer, has incorporated this new bumper structure to their vehicles.Copyright