Development of Mathematical Models for Evaluating Child Occupant Impact Dynamics and Intrusions of the Vehicle Structure

2008 ◽  
Author(s):  
Ahmed M. Elmarakbi
Keyword(s):  
Dynamic Response ◽  
Mathematical Models ◽  
Seat Belt ◽  
Vehicle Body ◽  
Design Stage ◽  
Injury Criteria ◽  
Front End ◽  
Vehicle Structure ◽  
Lumped Masses ◽  
Child Occupant

Two mathematical models are developed and analyzed in this paper to predict the dynamic response in vehicle crashes. The first model is developed to capture the front-end intrusion of the vehicle structure in frontal collision. The second model is proposed to define the interaction between the child occupant and vehicle passenger compartment and to predict the acceleration injuries during a sudden impulse load. In these mathematical models, the bumper and vehicle body are defined by lumped masses and longitudinal rails of the front-end structure are defined by plastic springs. Moreover, the child occupants are considered as lumped masses, connected to the child seat and vehicle body masses by means of restraint systems. The occupant restraint characteristics of seat belt are represented by stiffness and damping elements. To obtain the dynamic response of the occupant, the equations of motion of the vehicle impact system in both full and offset scenarios are developed and analytically solved using Incremental Harmonic Balance Method (IHBM). The injury criteria, child’s acceleration and vehicle’s font-end deformation, are used to interpret the results. It is demonstrated from the simulations that the dynamic response and injury criteria are easily captured and analyzed. It is also shown that the mathematical models are flexible, useful in optimization studies and it can be used at initial design stage.

Dynamic Analysis of Tram Vehicles Coupled With the Track System Based on Staggered Iterative Algorithm

2020 ◽  
Vol 15 (6) ◽  
Author(s):  
Yao Shan ◽  
Binglong Wang ◽  
Shunhua Zhou ◽  
Jiawei Zhang ◽  
Aijun Huang
Keyword(s):  
Dynamic Response ◽  
Soft Soil ◽  
Low Frequency ◽  
Vehicle Body ◽  
Frequency Range ◽  
Fe Method ◽  
Coupling System ◽  
Durability Design ◽  
Track System ◽  
Vehicle Structure

Abstract In recent years, a large number of tram–tracks have been constructed in typical soft soil area of China. Infrastructure defects due to the differential foundation settlement are serious issues in this area. To ensure the operation safety of the tram, the influence of different infrastructure defects on the dynamic response of the tram–track system has been investigated in this paper. A dynamic model of a five-module 100% low-floor tram vehicle coupled with a slab track system is developed based on a finite element (FE) method and multibody kinematics. The articulation between different vehicle modules, the wheel–rail nonlinear contact, pad failures, and a cavity in the subgrade have been taken into account in this model. The dynamic response of the vehicle–track coupling system to different operation speeds and infrastructure defects are calculated. Results indicate that the vibration energy of the vehicle body is mainly distributed in the frequency range below 1.5 Hz. This frequency range should be paid special attention in the durability design for the vehicle structure. When the number of the failure pads is larger than 3, the pad failure in tram–track has significant influence on the system dynamic response. A cavity in subgrade has a limited effect on high frequency vibrations (above 100 Hz) of the rail, while the low frequency vibrations (below 75 Hz) of the rail can be obviously increased by cavities in subgrade. The model can be used in the optimization of suspension parameters and the tram vehicle–track coupled vibration analysis.

Vibration Control in Industrial Plant: A Methodological Approach

1987 ◽  
Vol 109 (4) ◽  
pp. 335-342
Author(s):  
D. Miconi
Keyword(s):  
Mathematical Models ◽  
Vibration Control ◽  
Methodological Approach ◽  
Graphic Representation ◽  
Industrial Plant ◽  
Design Stage ◽  
Machine Foundation ◽  
Damping Characteristics ◽  
Effective Instrument

The present paper is a report on the construction of nomograms to ascertain the domain of elastic-inertial-damping characteristics required in vibrating machine-foundation systems, in order to ensure that ergonomic and other technical constraints are complied with. Nomograms, which are the graphic representation of mathematical models in nondimensional form, prove to be an effective instrument for orientation in the design stage.

Characterization of Frontal Crash Pulses

2000 ◽  
Author(s):  
Hikmat F. Mahmood ◽  
Fadhel Aouadi
Keyword(s):  
Pulse Duration ◽  
Test Data ◽  
Frontal Crash ◽  
Design Information ◽  
Injury Criteria ◽  
Front End ◽  
Time Zones

Abstract This paper presents test data of more than 30 vehicles of different manufacturer, weight and front-end length. The relationships between the vehicle frontal NCAP pulse, the dummy response and the vehicle characteristics are shown in many figures. Vehicle frontal pulses were characterized and analyzed by considering different time zones within the pulse duration: bumper effect zone (0 ms. to 5 ms.), engine effect zone (18 ms. to 35 ms.), dummy engagement zone (48 ms. to 68 ms.). Also, ratios and delays between rocker pulse and the dummy chest and head pulses are computed and analyzed. The purpose of this study is not to develop a crash pulse but to generate design information that can assist in the design of front-end structure to meet injury criteria.

Impact Simulation of Hydro-formed Front End Vehicle Structure

2006 ◽  
Author(s):  
Ruth Gao ◽  
Ligong Pan ◽  
Tau Tyan ◽  
Kumar Mahadevan ◽  
Omar Ghouati ◽  
...  
Keyword(s):  
Impact Simulation ◽  
Front End ◽  
Vehicle Structure

Design and Validation of a Component Head Injury Criteria Tester for Aerospace Applications

2005 ◽  
Author(s):  
Hamid M. Lankarani ◽  
C. S. Koshy ◽  
C. K. Thorbole
Keyword(s):  
Head Injury ◽  
Seat Belt ◽  
Impact Angle ◽  
Head Impact ◽  
Aircraft Cabins ◽  
Aerospace Applications ◽  
Injury Criteria ◽  
Test Conditions ◽  
Head Injury Criteria ◽  
Impact Events

The compliance with Head Injury Criteria (HIC) specified in 14 CFR 23.562 [1] and CFR 25.562 [2] poses a significant problem for many segments of the aerospace industry. The airlines and the manufacturers of jet transports have made claims of high costs and significant schedule overruns during the development and certification of 16G seats because of the difficulties encountered in meeting this requirement. The current practice is to conduct Full Scale Sled Tests (FSST) on impact sleds. This approach can be expensive, since a new seat may be needed for each test. Moreover, some consider the HIC sensitive to changes in the test conditions, such as sled pulse, seat belt elongation, etc., resulting in HIC results from FSSTs showing poor repeatability. These difficulties make it desirable to devise a cheaper, faster, and more repeatable alternative to FSSTs. This paper describes an attempt to address these issues by designing a device, the National Institute for Aviation Research (NIAR) HIC Component Tester (NHCT) using various multibody tools. This device was then fabricated and its performance evaluated against FSSTs conducted under similar test conditions for some typical impact events that occur in an aircraft cabins e.g. impact with bulkheads. The factors compared for this evaluation are the head impact angle, head impact velocity, HIC, HIC window, peak head C.G. resultant acceleration, average head C.G. resultant acceleration, and head C.G. resultant acceleration profiles. The results of these evaluations show that the NHCT already produces test results that correlate significantly with FSST results for impact targets such as bulkheads and its target envelope is expected eventually to include objects such as seat backs.

Use of Stochastic Analysis for FMVSS210 Simulation Readiness for Correlation to Hardware Testing

2002 ◽  
Author(s):  
Amit Sharma ◽  
Ashok Deshpande ◽  
Raviraj Nayak
Keyword(s):  
Seat Belt ◽  
Design Sensitivity ◽  
Response Model ◽  
Latin Hypercube Design ◽  
Static Test ◽  
Analytical Simulation ◽  
Vehicle Structure ◽  
Input Parameters ◽  
Explicit Dynamic ◽  
Hardware Test

The FMVSS210 regulation establishes requirements for seat belt assembly anchorages to be strong enough for effective occupant restraint. The belt separation from the vehicle structure in crash tests needs to be avoided. Federal government mandate requires use of Pelvic and Torso Body Blocks for testing belt anchor strengths for lap and shoulder belts respectively. The belt anchorages are expected to withstand loads of 13.34 kN if both lap and shoulder belts are used and 22.24 kN if only lap belts are used. The analytical simulation of the hardware test is done using explicit dynamic code LS-DYNA. Hardware testing is of quasi-static nature while the simulation uses the dynamic code. However the analysis could be made to approach the quasi-static test by adjusting some input parameters in the simulation. In addition some input parameters need adjustment for making the model robust and to make it correlate to the hardware test. This study involves the use of Optimal Symmetnc Latin Hypercube Design to explore the design space, and to develop a fast surface response model. This response model can be viewed as a surrogate model to the actual LS-DYNA simulation and is used in this work to rank the input parameters by the percent contdbution they make towards the variation of the desired output responses. After determining the fit of the response model, it is used to perform the stochastic simulation. The confidence interval for test correlation prediction can then be estimated. This technique can further be used to do design sensitivity studies and for optimizing the vehicle structure with respect to FMVSS210 regulation.

Responses of Hybrid-III 50th and Thor-NT 50th in Sled Tests With Different Seat Belt Pretensioner Configurations

2006 ◽  
Author(s):  
Chang In Paek ◽  
Greg Shaw ◽  
Jeff Crandall ◽  
Yoon Ho Baek ◽  
Ol Suk Ko
Keyword(s):  
Head Injury ◽  
Seat Belt ◽  
Relative Sensitivity ◽  
Forward Movement ◽  
Similar Test ◽  
Injury Criteria ◽  
Hybrid Iii ◽  
Head Injury Criteria ◽  
Test Repeatability

This study quantifies the effectiveness of the various seat belt pretensioner configurations relative to the no pretensioner condition and defines the relative sensitivity of the Hybrid-III 50th and THOR-NT 50th percentile male anthropomorphic test devices to pretensioner effects. The results of this study indicate that pretensioners reduced the chest accelerations and Head Injury Criteria (HIC) of both Hybrid-III and THOR-NT dummies. In addition, the pretensioners reduced the chest forward movement by providing restraint earlier in the event. The dual pretensioners and the retractor pretensioners were more effective than the buckle pretensioner and the no pretensioner conditions. Although the Hybrid-III and THOR-NT were different in construction and sitting depth, the Hybrid-III and THOR-NT's responses to the pretensioner conditions were similar. Test-to-test repeatability was acceptable for both dummies.

RESEARCH OF RELIABILITY AT THE DESIGN STAGE OF COMPLEX TECHNICAL SYSTEMS

2020 ◽  
pp. 1-20
Author(s):  
V. M. Trukhanov ◽  
S. S. Basova ◽  
G. V. Trukhanov ◽  
G. I. Kuprovskiy
Keyword(s):  
Mathematical Models ◽  
Present Article ◽  
Design Stage ◽  
Calculation Methods ◽  
Reliability Indices ◽  
Design Reliability ◽  
Complex Technical Systems ◽  
Technical Systems

The issues of nomenclature choice of reliability indices and methods of reliability distribution between components of product have been considered in the present article. Calculation methods of design reliability of expensive nondiscarding objects like movable mountings and also mathematical models of design reliability, which taking into account random and nonrandom failures. The technique of calculation and achievement of required level reliability has been represented.

Application of Optimal Control Theory to the Synthesis of High-Speed Cam-Follower Systems. Part 1: Optimality Criterion

1983 ◽  
Vol 105 (3) ◽  
pp. 576-584 ◽  
Author(s):  
M. Chew ◽  
F. Freudenstein ◽  
R. W. Longman
Keyword(s):  
Optimal Control ◽  
Control Theory ◽  
Dynamic Response ◽  
Optimal Control Theory ◽  
High Speed ◽  
Integrated Approach ◽  
Optimization Criterion ◽  
Design Stage ◽  
Trade Offs ◽  
Cam Follower

The synthesis of the parameters governing the dynamic response of high-speed cam-follower systems ideally involves an integrated approach capable of carrying out the tradeoffs necessary to achieve optimum dynamic response in the design stage. These trade-offs involve a balance between the system characteristics at the output and at the cam-follower interface. In this investigation optimal-control theory has been demonstrated to be a useful tool in developing such a tradeoff. Part 1 describes the development of an optimization criterion while Part 2 describes the application of optimal-control theory to the evaluation of system parameters satisfying the optimization criterion.

scholarly journals Modelling and Dynamic Response Characteristics Study of a PAM Bionic Kangaroo Leg Suspension

2020 ◽  
Vol 25 (2) ◽  
pp. 254-265
Author(s):  
Yong Song ◽  
Jiahao Shi ◽  
Zhanlong Li ◽  
Jinyi Lian ◽  
Qinglu Shi ◽  
...  
Keyword(s):  
Fuzzy Control ◽  
Dynamic Response ◽  
Pid Control ◽  
High Performance ◽  
Artificial Muscle ◽  
Vehicle Body ◽  
Passive Mode ◽  
Response Characteristics ◽  
Dynamic Response Characteristics ◽  
Vehicle Suspension System

A PAM (pneumatic artificial muscle) bionic kangaroo leg suspension is proposed on the basis of a kangaroo leg structure evolved from long-term hopping; the modelling and characteristics research are conducted to pursue a high-performance vehicle suspension system. Based on the PAM and kangaroo leg bone proportions, the bionic suspension structure is constructed by analysing and refining the kangaroo leg structure and functions. The dynamic equations are derived by the Lagrange's Equations considering the rods system features and an Adams simulation model is built up to study the damping performance and parameter characteristics of the suspension. Moreover, a co-simulation of Adams and Matlab is performed under fuzzy control and PID control. The dynamic response characteristics of the suspension is simulated and analysed under the passive and active modes in the time and frequency domains. The result indicates that the vibration and shock of the vehicle body can be reduced effectively by the proposed suspension in passive, fuzzy control and PID control modes; compared with the passive mode, the damping performance of the suspension is better under the active control. The fuzzy control and the PID control are effective to reduce the suspension transmissibility, especially in the medium frequency ranges, and the two control effects are better than that of the passive mode in most frequency bands. The study result of this paper can provide a reference for the research and development of high-performance bionic suspension.

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