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Showing 13 results for Crashworthiness

M. Abbasi, R. Kazemi, A. Ghafari Nazari,
Volume 1, Issue 3 (5-2011)
Abstract

Parametric design optimization of an automotive body crashworthiness improvement is presented. The thicknesses of parts are employed as design variables for optimization whose objective is to increase the maximum deceleration value of the vehicle center of gravity during an impact. Using the Taguchi method, this study analyzes the optimum conditions for design objectives and the impact factors and their optimal levels are obtained by a range analysis of the experiment results. A full frontal impact is implemented for the crashworthiness simulation in the nonlinear dynamic code, LS-DYNA. The controllable factors used in this study consist of the six inside foreheads structural parts, while design parameters are relevant thicknesses. The most interestingly the maximum deceleration of the vehicle center of gravity is reduced by 20% during a full frontal impact while several parts experience mass reduction.
N. Tavassoli, A. Darvizeh, M. Darvizeh,
Volume 2, Issue 1 (1-2012)
Abstract

Car body lightening and crashworthiness are two important objectives of car design. Due to their excellent performance, composite materials are extensively used in the car industries. In addition, reducing the weight of vehicle is effective in decreasing the fuel consumption. Hat shape energy absorber is used in car’s doors for side impact protection. The aim of these numerical models and experimental tests is to unveil some important fact about using composite materials in hat shape energy absorber and also show the effect of orientation angles on the amount of energy absorption. The effects of different orientation angles on crushing behavior of hat shape structure are presented.
R. Mirzaamiri, M. Esfahanian, S. Ziaei-Rad,
Volume 2, Issue 3 (7-2012)
Abstract

During the design and development of truck cabins, the safety of the driver and the front seat passenger in an accident is an important task and should be considered. The cab must be designed in such a way that in an accident a sufficient survival space is guaranteed. The aim of this study is to investigate the behavior of Iran Khodro (IKCO) 2624 truck subjected to a complex crash test according to regulation ECE-R29. This regulation is a comprehensive European regulation consisting of three tests: 1-Front impact test (Test A), 2- Roof strength test (Test B), 3-Rear wall strength test (Test C). These tests do not consider the safety of the occupant directly however, a III-50th% dummy was used to assess the cab’s deformations relative to the driver survival space. A 3D finite element model of the cab and chassis was developed and subjected to tests by using LS-DYNA software. The results indicate that the cab complied with Test A and C successfully while it passed Test B marginally. Finally, two solutions are suggested and implemented to improve the cab’s response for Test B.
A. Khalkhali, S. Samareh Mousavi,
Volume 2, Issue 3 (7-2012)
Abstract

In order to reduce both the weight of vehicles and the damage of occupants in a crash event simultaneously, it is necessary to perform a multi-objective optimization of the automotive energy absorbing components. In this paper, axial impact crushing behavior of the aluminum foam-filled thin-walled tubes are studied by the finite element method using commercial software ABAQUS. Comparison of the present simulation results with the results of the experiments reported in the previous works indicated the validity of the numerical analyses. A meta-model based on the feed-forward artificial neural networks are then obtained for modeling of both the absorbed energy (E) and the peak crushing force (Fmax) with respect to design variables using those data obtained from the finite element modeling. Using such obtained neural network models, a modified multi-objective GA is used for the Pareto-based optimization of the aluminum foam-filled thinwalled tubes considering three conflicting objectives such as energy absorption, weight of structure, and peak crushing force.


S.a. Yousefsani, J. Rezaeepazhand, S.a. Maghami,
Volume 3, Issue 1 (3-2013)
Abstract

Material properties and geometry are two important design parameters which their effects should be considered in a crashworthiness analysis. In this paper, the axial impact of metallic and hybrid energy absorbing thin-walled tubes with poly-gonal cross-section is simulated using LS-DYNA software. The combined effects of changing the geometry and material properties on the mass specific energy absorption (MSEA) as well as the mean and maximum crush forces are investigated. To compare the results, all metallic tubes have identical thickness, length, and circumference. The hybrid tubes are made of the same metallic tubes which are reinforced with special composite overlays. These materials are intentionally selected in such a way that the effects of yield strength and Young’s modulus can be separately investigated. The results show that, in contrast with the current belief, there are some metallic and hybrid tubes with non- circular cross-section shapes, which have better mass specific energy absorption capabilities than the circular ones during the impact.
A. Khalkhali, M. Afroosheh, M.r. Seyedi,
Volume 4, Issue 1 (3-2014)
Abstract

In this paper, numerical simulation of FRP composite cylinder tubes progressive crushing processes is conducted using LS-Dyna. Details on the numerical modeling strategy are given and discussed. It is found that triggers introduced in the numerical simulation can effectively model the bevel trigger at the end of the tubular specimens. It is also found that two-layer finite element model based on the TsaiWu failure criteria is effective in representing the crushing failure mode of the tubular composite specimens and energy absorption characteristics. Employing GEvoM software, two meta-models are then obtained for modeling of both the absorbed energy (E) and the peak crushing force (Fmax) with respect to geometrical design variables using input output data obtained from the finite element modeling. Comparison between obtained meta-models and numerical results in both of training and testing sets show good approximation by using obtained polynomial models.


H. R. Zarei,
Volume 5, Issue 3 (9-2015)
Abstract

This research deals with axial and oblique impact crash tests on simple and hybrid composite tubes. Axial and oblique impact tests have been generated on simple and hybrid composite tubes with one, two and three layers. A drop test rig was used to conduct the experiments. Furthermore, in order to gain more detailed knowledge about the crash process, finite element simulations of the experiments have been performed. The explicit finite element code LS-DYNA was used. The simple tube and the composite hybrid tubes are modeled with thin layer shell elements. The elastic-plastic material model was used for the aluminum tube and the Chang-Chang failure model was implemented for the composite layers. In terms of finding more efficient (higher energy absorption) and lighter crash absorbers particularly, the absorbed energy and specific energy absorption are considered in this research. E SAE


A. Khalkhali, M. Sarmadi, A. Bodaghi,
Volume 6, Issue 1 (3-2016)
Abstract

This study aims to numerically investigate on the crashworthiness of thin-walled square tubes by consideration of 3-D oblique loading. In this type of loading, direction of loading is defined by using two spatial angles relative to the position of the tube. To this aim, finite element (FE) analysis is employed to simulate the loading for 8 different numerical models with different loading orientation. Subsequently, load-displacement diagrams as well as deformation shapes during the loading are derived for each model. Moreover, a study is done on the tube collapse mode for each case. Effect of loading orientation and tube thickness on the maximum crushing load and energy absorption are also studied via a parametric study on the FE simulations. Results indicated a different trend for all cases of 3D oblique loading compared to axial loading. This study highlights the significance of consideration of a 3D orientation in analysis of crushing behavior of thin-walled tubes.


A. Balaei Sahzabi, M. Esfahanian,
Volume 7, Issue 2 (6-2017)
Abstract

This article investigates the effects of using a thin-walled structure in the chassis front rails in the automotive industry. In frontal accidents, the front rails of the vehicle chassis, increases vehicle crash-worthiness and occupants’ safety by plastic deformation, energy absorption, increasing the crash duration and reducing the load and injuries to the occupants. The objective is to optimize the thin-walled structure of the bumper and the direct beams in the front chassis rails. An explicit FEM full vehicle model with a dummy, safety belts, and air bags are used for the modeling and analysis of the applied loads on the vehicle and the occupants. The FMVSS No. 208 and ECE No. 94 standards are considered for the simulation of a vehicle accident. Finally, the proper model will be selected based on the results.
 
F. Djamaluddin, S. Abdullah, A.k. Arrifin, Z.m. Nopiah,
Volume 7, Issue 2 (6-2017)
Abstract

In automotive industry, foam-filled structures have aroused increasing interest because of lightweight and capacity of energy absorption. Two types of foam filled thin walled structures such as the uniform foam filled (UF) and the functionally graded foam (FGF). To improve crashworthiness performance, FGF are used to fill structures, unlike existing uniform foam materials. In addition, by seeking for an optimal design systematically, some computational optimization signifies a more effective tool to find the best crashworthiness design of structures,. This paper will an exhaustive review of the previous studies of simulation-based optimization such as metamodels, objective functions, design variables, design of experiments, optimization techniques of crashworthiness of tubes.
K. Annamalai, G. Balaji,
Volume 7, Issue 4 (12-2017)
Abstract

Fillers can be employed as reinforcement in the design of automobile crash boxes to improve its performance in terms of energy absorption, expected crushing fashion and initial peak force magnitude. The current research focuses on the investigation of crashworthiness of the high-strength steel (HSS) columns filled with reinforced aluminium honeycomb fillers. The crashworthiness of HSS steel crash boxes embedded with aluminium honeycomb of varying thickness and  cell sizes are investigated. Five variants of honeycomb thickness, namely; Thickness-1, Thickness-2, Thickness-3,Thickness-4, Thickness-5 and six variants of honeycomb cell size, namely; CellSize-1, CellSize-2, CellSize-3, CellSize4, CellSize-5 and CellSize-6 are considered for the crash box analysis. Numerical crash analysis is performed for the novel reinforced sandwich honeycomb separated by steel plates in HSS crash box. A further study is also performed by inducing V-Notch triggers in the honeycomb to evaluate the effect of crashworthiness parameters. A comparative numerical investigation is performed to realize the effect of geometric parameters on the crashworthiness variables of crash boxes for low-velocity impact. The force versus displacement curves were derived and analyzed for each parameter variations and detailed comprehension of deformation pattern and energy absorption are provided. The objectives of the present work is to showcase the effect of honeycomb geometric parameters like thickness and cell size on crashworthiness parameters for low-velocity impact and also to represent the effect of sandwich honeycomb and honeycomb with V-Notch triggers methodology on the crashworthiness parameters like initial peak force (IPF), energy absorption (EA), specific energy absorption (SEA) and crush force efficiency (CFE)
 
K. Annamalai, G. Balaji,
Volume 8, Issue 1 (3-2018)
Abstract

Fillers can be employed as reinforcement in the design of automobile crash boxes to improve its performance in terms of energy absorption, expected crushing fashion and initial peak force magnitude. The current research focuses on the investigation of crashworthiness of the high-strength steel (HSS) columns filled with reinforced aluminium honeycomb fillers. The crashworthiness of HSS steel crash boxes embedded with aluminium honeycomb of varying thickness and cell sizes are investigated. Five variants of honeycomb thickness, namely; Thickness-1, Thickness-2, Thickness-3, Thickness-4, Thickness-5 and six variants of honeycomb cell size, namely; CellSize-1, CellSize-2, CellSize-3, CellSize4, CellSize-5 and CellSize-6 are considered for the crash box analysis. Numerical crash analysis is performed for the novel reinforced sandwich honeycomb separated by steel plates in HSS crash box. A further study is also performed by inducing V-Notch triggers in the honeycomb to evaluate the effect of crashworthiness parameters. A comparative numerical investigation is performed to realize the effect of geometric parameters on the crashworthiness variables of crash boxes for low-velocity impact. The force versus displacement curves were derived and analyzed for each parameter variations and detailed comprehension of deformation pattern and energy absorption are provided. The objectives of the present work is to showcase the effect of honeycomb geometric parameters like thickness and cell size on crashworthiness parameters for low-velocity impact and also to represent the effect of sandwich honeycomb and honeycomb with V-Notch triggers methodology on the crashworthiness parameters like initial peak force (IPF), energy absorption (EA), specific energy absorption (SEA) and crush force efficiency (CFE).


Masoud Afrousheh, Javad Marzbanrad, Sanaz Abdollahzadeh,
Volume 9, Issue 4 (12-2019)
Abstract

Thin-walled structures play an important role in absorbing the energy in a low impact crash of vehicles up to saving lives from high impact Injury. In this paper, the thin-walled columns by using a hybrid Design of Experiments (DOE) and Ant Colony Algorithm (ACO) has been optimized. The analysis of the behavior of the nonlinear models under bending load is done using finite-element software Abaqus. The objective is to study the performance geometrically parameters of the columns using DOE-ACO approach.
DOE method is being applied to determine the effects of cross-sections, material, and thickness on the energy absorption; and the ACO method is used for finding more accurate thickness on energy absorption. Four types of thin-walled cross-sections, i.e., circle, ellipse, hexagon, and square are used in this study. The optimized results of DOE method show that aluminum alloy (Al-6061) and high strength low alloy steel (HSLA) square columns have a higher energy absorption in comparison with the other cross-sections. However, the amount of absorbed energy in two types of columns is equal but, 50 percent weight reduction may be seen in Al-6061 columns. The columns are re-optimized by ACO to find the best thickness in the last step.
In the following, by topology optimization participation, a new plan is proposed by the same thickness and 50% less weight, that has a higher crashworthiness efficiency by increasing SAE more than 70%. As a result of this plan is bridging the gap between standard topological design and multi-criteria optimization.
 

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