Computational simulation of frontal impact of motorcycle telescopic fork

This paper presents modelling aspects of a high fidelity finite element model of a motorcycle telescopic fork. For validation purpose, a series of impact tests of which a frontal impact load imposed on the individual fork by a rigid striker was conducted using factorial experiment approach. The model was then used to simulate all the impacts accordingly. The outcomes were evaluated in terms of permanent deformations of the fork, energy dissipated in the impact, and the velocity and displacement time histories of the striker. The overall performance and sensitivity of the model was also assessed using the factorial analysis. The deviations of time histories data were quantified by mean error, mean absolute error and root mean square error. The key responses of the fork were found to be successfully simulated and compared well to the test results. The computed largest value among the respective metrics over the total errors was 6.2% of which corresponding to the root mean square error of the displacement time histories data, whereas others were less than 3%. It is thus concluded that the fork model has been successfully validated and the modelling methods has been established. Recommendations for improvements were also given in the paper

Heavy Military Land Vehicle Mass Properties Estimation Using Hoisting and Pendulum Motion Method

Mass properties such as the centre of gravity location, moments of inertia, and total mass are of great importance for vehicle stability studies and deployment. Certain parameters are required when these vehicles need to be arranged inside an aircraft for the carrier to achieve proper mass balance and stability during a flight. These parameters are also important for the design and modelling process of vehicle rollover crash studies. In this study, the mass properties of a military armoured vehicle were estimated using hoisting and pendulum method. The gross total weight, longitudinal and vertical measurements were recorded by lifting the vehicle using a mobile crane and the data were used to estimate the centre of gravity. The frequency of vehicle oscillation was measured by applying swing motion with a small angle of the vehicle as it is suspended on air. The centre of gravity and mass moment of inertia were calculated using the vector mechanics approach. The outcomes and limitations of the approach as discussed in details

Enhancement in critical current density and irreversibility field of bulk MgB2 by C and CaCO3 co-addition

Paper ash, a source of C and CaCO3, was used for the first time as a cheap form of sub-micron particles for doping. 0–10 wt% of the ash was added to Mg + 2B and in situ reacted at 850 ◦C for 30 min in flowing Ar atmosphere. The CaCO3 decomposed and reacted with B to form CaB6 as an impurity phase. Also, the Tc and the a-axis lattice parameter decreased with increasing ash content, which suggests that C substitution at boron sites occurred. Enhancement of high-field Jc(H), Hirr(T ) and Hc2(T ) was observed with an optimum level of about 5 wt% ash additio

Drop Weight Testing Rig Analysis and Design

Crashworthiness studies are becoming increasingly important in mechanical design, particularly with the new advancement of the computer simulation codes. These studies generally require material and prototype testing for both modelling and validation. Large percentages of these studies lie on the limits of medium strain rate, which could be achieved by a drop weight test rig. Therefore, the drop weight test rig becomes an essential tool for such research activities besides the universal quasi-static testing machines. This paper is devoted to the analysis and design of the drop weight impact-testing rig. First, the different aspects of the mechanical design such as the propulsion, guidance, and frame layout, foundation and energy aspects are presented and discussed. Then, the basic types of data retrieval and analysis systems applicable for drop weight impact testing machines are presented and discussed. Data retrieval components considered in this study include the sensors for load, acceleration, and velocity measurements, image acquisition including high-speed cameras and PC-based image acquisition system, and data acquisition including oscilloscope or PC-based data acquisition system which utilizes an AID card and application software for visualizing and analyzing of the results. At the end of this article the designed and constructed test machine is presented as a case study

Deformations’ predictions by utilizing load blast enhanced against structural arbitrary langrangian eulerian methodologies : an LS-DYNA numerical simulation study

Numerical simulation study to predict the transient (maximum) deformation of a rolled homogeneous armor plate which was loaded by the explosion of spherical trinitrotoluene bomb by using the ‘load blast enhanced’ and ‘structured arbitrary langragian eulerian’ methodologies in LS-DYNA is reported in this paper. Three numerical simulation models that utilized the ‘load blast enhanced’ and three numerical simulation models that utilized the ‘structured arbitrary langragian eulerian’ methodologies in LS-DYNA were produced and their results were used to predict and validate the deformations of three blast experimental tests of rolled homogeneous armor plates obtained from a published paper. This study showed that the numerical simulation results from the ‘load blast enhanced’ methodology gave better agreement than the ‘structured arbitrary langragian eulerian’ methodology with an average percentage differences of around 17% for all three cases

Experimental study on energy absorption characteristics of motorcycle front wheel—tyre assembly in frontal impact

This article presents a study on the frontal impact properties of the motorcycle front wheel—tyre assembly using squared change of velocity and dissipated impact energy as response variables. The laboratory-scaled impact tests were performed on the wheel—tyre assemblies using pendulum impact test apparatus according to a 25−1 V fractional factorial design with four replicates. Five parameters that are included in the experiment were impact speed (S), impact mass (M), tyre inflation pressure level (P), contact geometry of striker (G) and offset distance of impact location from axle (D). The test specimen used in the study was a spoked wheel of size 1.40 × 17. Minitab has been employed to support the entire experimental process. The collected experimental data were organized, and factorial analysis was performed. The significant factors influencing the impact responses of the wheel—tyre assembly were identified, which are S, M, P, D, SM and SD. The associated empirical models were then established and presented, followed by the factorial plots for the respective significant factors. The curves demonstrating the impact response of the wheel—tyre assembly under various impact conditions were generated from the developed models to illustrate the impact response of the wheel—tyre assembly under various impact conditions within the experimental region. Comparison was made to the values of dissipated energy predicted by the developed model and the values of impact energy from fundamental kinetic energy equation, and it was found that the model is consistent with the physical condition within the experimental region

Development of Empirical Model for the Impact of Motorcycle Front Wheel-Tyre Assembly

In engineering terms, the residual deformation on structural component is correlated to the dissipated energy, the change of momentum, or the change of speed during the impact. Many force-deflection models have been successfully developed for automobiles. However, such engineering model is not well developed for two-wheel motor vehicles due to lack of correlation information between the change of velocity and the structural damage, especially the frontal components such as wheel-tyre assembly which encounter the first and direct impact in frontal collision. The present study has thus been conducted which intended to lay out a route for developing the empirical models for motorcycle front wheel-tyre assembly that can be utilized to assess the impact velocities or change of velocities of a motorcycle in frontal collision based on the post-impact residual deformation of the wheel-tyre assembly. An experimental approach has been adopted for the present study. The test specimens used was the original front wheel-tyre assembly of Malaysia national motorcycle, KRISS 110. The impact tests on motorcycle wheel-tyre assembly have been successfully conducted by employing a pendulum impact test apparatus developed in-house in order to better suit to the experiment requirements. High-speed camera has been used to capture the deformation progress of the wheel-tyre assembly during the impact phase at a rate of 500 frame-per-seconds. Statistical computer program, Minitab Version 13, has been adopted to support the entire experimental process. Five out of eight parameters that are predetermined to be important on impact responses of wheel-tyre assembly have been identified as design factors. These factors are impact speed, impact mass, tyre inflation pressure level, contact geometry of striker, and vertical offset distance of impact location from a wheel axle. A fractional factorial design has been incorporated in the experimental design. Four response variables have been selected, which are, maximum residual crush sustained by the wheel-tyre assembly, normalized area of deformation of the wheel, squared change of velocity of the striker and dissipated impact energy of the wheel-tyre assembly. Regression analysis has been performed in order to yield various possible empirical models in relating dissipated energy to either maximum residual crash or normalized area of deformation. The analysis shows good correlation in which the values of and are greater than 96% for all responses, except that in linear regression for the response , which is about 83%. Factorial analysis has also been performed and the significant factors influencing the impact responses of the wheel-tyre assembly have been identified. The corresponding empirical models for predicting the deformation sustained by the wheel within the experimental design region have also been established. Based on the developed models, dynamic impact characteristics of the wheel-tyre assembly under various impact conditions were discussed

Computational modelling of small motorcycle crashes and experimental validation

Researches in motorcycle crash simulations have been largely focused on the large motorcycles that are commonly found on the roads in developed nations, whereas for the small motorcycles that are used as daily transport in developing nations, the development is relatively far lacking. The present study was thus set out to create and validate a finite element model of a small motorcycle with fully deformable capability for simulating frontal crashes, and to establish guidelines for the entire development process. The Malaysian national motorcycle, Modenas Kriss 110, was selected as the reference motorcycle and the model was developed in LS-DYNA environment. The front wheel and fork which often experience severe and highly dynamic deformations in frontal crashes were modelled to be fully deformable for capturing detail deformation mechanisms and also interactions involved. The models of these crucial subassemblies were validated separately against experimental data. The overall validity and sensitivity of the models were also assessed using factorial experiment approach.The validated front subassemblies were then assembled together with other parts to form the full motorcycle model. A specially designed apparatus and the associated measuring technique were developed to determine the location of centre of gravity and mass moment of inertia of the actual motorcycle. These inertial properties were incorporated in the full motorcycle model. The full motorcycle model was validated against an actual laboratory-based full motorcycle impact test. The global behaviour of the motorcycle and the major deformations sustained particularly by the front wheel and fork were compared. Time histories of motorcycle kinematics were validated against the test data using Roadside Safety Verification and Validation Program(RSVVP). The computed values of the metrics Sprague-Geers MPC and ANOVA are all met the acceptance criteria: 17.6%(magnitude), 16.5% (phase), 24.2% (comprehensive), 0.9% (average) and 21.6% (standard deviation) for the horizontal acceleration; -11%, 22.7%, 25.2%, 0.8% and 19.8% for the corresponding metrics for the vertical acceleration. It is thus concluded that the validated motorcycle model was successfully developed. Detail modelling aspects in developing the models including major numerical instabilities encountered and proposed resolutions, and also limitations and discrepancies exhibited by the models were discussed. The robustness of the model was demonstrated by its capability in simulating severe deformations and the geometric failure of the rim. A guideline to effectively and systematically develop a high fidelity finite element model of a small motorcycle for use in simulating frontal collision of a motorcycle was established

Simulation SPH de l’arrêt et propagation de fissure sous impact dans un PMMA résistant au choc

National audienceL’utilisation de PMMA résistant aux chocs (RT-PMMA) comme fenêtre de protection pour les structures en ingénierie nécessite une évaluation de sa capacité d’arrêt de fissure sous chargement par impact. À cette fin, une série d’essais d’impact de type Kalthoff et Winkler (KW) a été réalisée sur plusieurs nuances de RT-PMMA, mettant en évidence le rôle de la concentration de nanoparticules d’élastomères. Sur la base de ces essais, la présente étude vise à reproduire numériquement les conditions d’amorçage et de propagation de fissures fragiles dans le RT-PMMA, et plus particulièrement à étudier les effets de divers critères de rupture pour reproduire l’arrêt de fissure, ce qui est loin d’être trivial et donc rarement abordé dans la littérature

Numerical simulation of crack arrest in impact loaded shock-resistant PMMA using SPH

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