scholarly journals Application of Fractional Calculus to Frontal Crash Modeling

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Miodrag Zigic ◽  
Nenad Grahovac
Keyword(s):  
Dry Friction ◽  
Initial Conditions ◽  
Viscoelastic Model ◽  
Special Treatment ◽  
Fractional Order Systems ◽  
Frontal Impact ◽  
Deformation History ◽  
Frontal Crash ◽  
Frontal Part ◽  
Impact Problem

Fractional derivative viscoelastic model is used in the analysis of a frontal impact of a vehicle against a rigid obstacle. The frontal part of the vehicle is first modeled as a viscoelastic fractional rod and then it is modeled as two different viscoelastic fractional rods with a different length. In the second model also the friction is taken into account. A motion is analyzed during several phases because of both different lengths of the rods and the presence of a dry friction force in the later model. Governing systems of differential equations together with the corresponding initial conditions are derived. Parameter identification is done on the basis of the existing experimental results using the solution of a posed impact problem. What makes the problem more complex, regarding the second model, is the fact that it belongs to the class of nonsmooth fractional order systems, which require special treatment when dealing with deformation history during different motion phases.

Prehistoric Effect of the Stamping Process on the Crash Analysis of an Automobile under Frontal Impact

2013 ◽  
Vol 711 ◽  
pp. 149-154 ◽  
Author(s):  
Se Ho Kim
Keyword(s):  
Impact Load ◽  
Crash Analysis ◽  
Frontal Impact ◽  
Vehicle Model ◽  
Side Member ◽  
Frontal Crash ◽  
Full Vehicle ◽  
Load Carrying ◽  
Crash Characteristics ◽  
The Impact

In this paper, a frontal crash analysis is carried out with a full vehicle model in order to investigate the influence of stamping effects of auto-body members on the crash characteristics of the vehicle. Stamping effects are considered for load carrying members such as the front side member and the rear lower. From the analysis result considering stamping effects, it is conformed that stamping history has to be considered for longitudinal members simultaneously that transfer the impact load under the frontal impact. Comparison of simulation result with experimental one also shows that the prediction accuracy of the crash analysis is remarkably improved.

Analysis of Lower Leg Injury of Occupant in Frontal Crash Tests Based on China NCAP Protocol

2011 ◽  
Vol 279 ◽  
pp. 400-405
Author(s):  
Zhi Xin Liu ◽  
Ren Jun Wan ◽  
Yong Wan Shi
Keyword(s):  
Test Data ◽  
Lower Leg ◽  
Lower Limbs ◽  
Vehicle Safety ◽  
Upper Limbs ◽  
Frontal Impact ◽  
Passenger Vehicle ◽  
Characteristic Parameters ◽  
Frontal Crash ◽  
Crash Tests

With the popularization of passenger vehicle safety devices such as safety belt, airbag and so on, the chance that occupant’s upper limbs were injured seriously was decreased significantly in frontal impact. However, the injury of occupant’s lower limbs became more and more severe, especially on lower leg injury. 37 groups of test data of China NCAP crash tests including full-frontal rigid crash and 40% offset deformable barrier crash were investigated in this paper, and lower leg injury distributing characteristic of drivers and passengers in these two kinds of crash configurations were obtained. Finally the effect rules of characteristic parameters on lower leg injury were summarized.

scholarly journals Fractional Dynamics of Computer Virus Propagation

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Carla M. A. Pinto ◽  
J. A. Tenreiro Machado
Keyword(s):  
Steady State ◽  
Fractional Derivative ◽  
Fractional Order ◽  
Initial Conditions ◽  
Computer Virus ◽  
Fractional Dynamics ◽  
Fractional Order Systems ◽  
Virus Propagation ◽  
Integer Order ◽  
Fast Transients

We propose a fractional model for computer virus propagation. The model includes the interaction between computers and removable devices. We simulate numerically the model for distinct values of the order of the fractional derivative and for two sets of initial conditions adopted in the literature. We conclude that fractional order systems reveal richer dynamics than the classical integer order counterpart. Therefore, fractional dynamics leads to time responses with super-fast transients and super-slow evolutions towards the steady-state, effects not easily captured by the integer order models.

Development of Validation Metrics for Vehicle Frontal Impact Simulation

2007 ◽  
Author(s):  
R. J. Yang ◽  
G. Li ◽  
Y. Fu
Keyword(s):  
Step Function ◽  
Evaluation Procedure ◽  
Frontal Impact ◽  
Physical Test ◽  
Frontal Crash ◽  
Validation Metrics ◽  
Impact Simulation ◽  
Commercial Code ◽  
The Difference ◽  
And Mathematics

This research addresses the development of validation metrics for vehicle frontal impact simulation. The model validation metrics provide a quantified measurement of the difference between CAE simulation and physical test. They are useful to develop an objective model evaluation procedure for eventually achieving the goal of zero or near zero prototyping. In this research, full frontal crash pulses are chosen as the key items to be compared in the vehicle frontal impact simulation. Both physics- and mathematics-based metrics are investigated. The physics-based metric include a method of using a simplified step function representation and the mathematics-based metrics include methods of wavelet decomposition, corridor violation plus area, and metrics used in a commercial code ADVISER, respectively. They are all correlated to subject matter experts’ rating through optimal weightings. A new metric, considering variabilities from both experts and metrics for frontal crash pulse, is proposed. One example is used to demonstrate its application.

Structure Improvement of the S Beam Based on the Safety of SUV

2010 ◽  
Vol 34-35 ◽  
pp. 675-680
Author(s):  
Jun Wu ◽  
Li Bo Cao ◽  
Tian Zhi Chen ◽  
Chen Chen Hu ◽  
Bing Hui Jiang ◽  
...  
Keyword(s):  
Rigid Body ◽  
Crash Test ◽  
Fe Model ◽  
Frontal Impact ◽  
Frontal Crash ◽  
Occupant Protection ◽  
Body Model ◽  
Crash Safety ◽  
Rigid Body Model ◽  
Structure Improvement

The S beam of a production SUV appeared instable deformation in frontal crash test, which was not beneficial to occupant protection. So the deformation of S beam should be controlled to improve the crashworthiness. Inner improvement structures were proposed according to the prototype S beam. A frontal crash FE model and a multi-rigid body model were developed and validated to investigate the crash safety of frontal impact. The influences of the improvements to the deformation of S beam and the energy absorption of longitudinal beams were analyzed by the FE model, and the injury risks of head and thoraces were analyzed by the multi-rigid body model. The better improvement structure was adopted in the frame for the crash test to validate the effectiveness of improved scheme, and the result shows better crash performance of frontal impact for prototype vehicle. Meanwhile, simulation study on crash safety of 40% offset crash were also conducted, which indicated that improved scheme was also beneficial for crash safety of 40% offset crash.

The Safety Assessment of Wheelchair Occupants in Road Passenger Vehicles in a Frontal Crash: A Computer Simulation

2007 ◽  
Vol 353-358 ◽  
pp. 2569-2572
Author(s):  
Young Shin Lee ◽  
Ki Du Lee ◽  
Hyun Kyoon Lim
Keyword(s):  
Safety Assessment ◽  
The Elderly ◽  
Upper Body ◽  
Restraint System ◽  
Frontal Impact ◽  
Automobile Accidents ◽  
Wheelchair Users ◽  
Frontal Crash ◽  
Occupant Restraint System ◽  
Passenger Vehicles

With the increasing needs of the more convenient transportation, wheelchairs are often used by people with mobility disabilities and the elderly people. However, as wheelchairs are primarily designed for the mobility assistive devices, not for the vehicle seats, wheelchair users are exposed to risk factors for neck and upper body injury caused by automobile accidents. In this paper, in accordance with the ANSI/RESNA WC-19, a fixed vehicle mounted wheelchair occupant restraint system (FWORS), wheelchair integrated restraint system (WIRS), and wheelchair integrated x-bend restraint system (WIXRS) are evaluated using computer simulations for the case when a wheelchair is subjected to the frontal impact (20 g, 48 km/h).

scholarly journals Dynamics of Coupled Oscillators Excited by Dry Friction

2008 ◽  
Vol 3 (3) ◽  
Author(s):  
Madeleine Pascal
Keyword(s):  
Dry Friction ◽  
Initial Conditions ◽  
Analytical Form ◽  
Contact Forces ◽  
Time Duration ◽  
Stick Slip ◽  
Coulomb’S Friction ◽  
The Masses ◽  
Stick Slip Motion ◽  
Two Degree Of Freedom

In this paper, we present an analytical method to investigate the behavior of a two-degree-of-freedom oscillator excited by dry friction. The system consists of two masses connected by linear springs. These two masses are in contact with a driving belt moving at a constant velocity. The contact forces between the masses and the belt are obtained assuming Coulomb’s friction law. Two families of periodic motions are found in closed form. The first one includes stick-slip oscillations with two switches per period, the second one is also composed of stick-slip motion, but includes three switches per period. In both cases, the initial conditions and the time duration of each kind of motions (stick or slip phases) are obtained in analytical form.

Initial Conditions and Initialization of Fractional Systems

2016 ◽  
Vol 11 (4) ◽  
Author(s):  
Massinissa Tari ◽  
Nezha Maamri ◽  
Jean-Claude Trigeassou
Keyword(s):  
Initial Conditions ◽  
Fractional Order Systems ◽  
Fractional Systems ◽  
Infinite Dimensional ◽  
State Variable ◽  
Future Behavior ◽  
Fractional Integrator ◽  
True State ◽  
Fractional System ◽  
Dimensional Variable

In this paper, the initialization of fractional order systems is analyzed. The objective is to prove that the usual pseudostate variable x(t) is unable to predict the future behavior of the system, whereas the infinite dimensional variable z(ω, t) fulfills the requirements of a true state variable. Two fractional systems, a fractional integrator and a one-derivative fractional system, are analyzed with the help of elementary tests and numerical simulations. It is proved that the dynamic behaviors of these two fractional systems differ completely from that of their integer order counterparts. More specifically, initialization of these systems requires knowledge of z(ω,t0) initial condition.

scholarly journals SIMULATION OF VEHICULAR FRONTAL CRASH-TEST

2012 ◽  
pp. 262-267
Author(s):  
TEJASAGAR AMBATI ◽  
K.V.N.S. SRIKANTH ◽  
P. VEERARAJU
Keyword(s):  
Automotive Industry ◽  
Development Time ◽  
Crash Test ◽  
Test Results ◽  
Crash Analysis ◽  
Frontal Impact ◽  
Frontal Crash ◽  
Huge Impact ◽  
Analysis Center ◽  
Crash Characteristics

This paper “SIMULATION OF FRONTAL CRASH-TEST” The simulation of vehicle crashes by using computer softwares has become an indispensible tool for shortening automobile development time and lowering costs. It also has huge impact on the crashworthiness of an automobile. This work reports on the simulated crash test of an automobile. The objective of this work is to simulate a frontal impact crash of an automobile and validate the results. The aim is also to alter some of the materials of the components with a view to reduce the forces experienced during the crash. Computer models were used to test the crash characteristics of the vehicle in the crash. The model used here was that of a Chevrolet C1500 pick-up truck. The software used for the simulation is LS-DYNA. It is widely used by the automotive industry to analyze vehicle designs. It accurately predicts a car's behavior in a collision. The results obtained by the simulation were then validated by comparing it with the test results of the same test performed by the NCAC (National Crash Analysis Center).

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