Crash Box Research Articles

Crashworthiness design of crash box filled with negative Poisson's ratio based on horn structure

In order to improve the crashworthiness of the crash box, the cattle horn is selected as a bionic object. A crash box filled with negative Poisson's ratio honeycomb based on horn structure was designed by extracting its excellent structural characteristics of impact resistance. The axial deformation modes and energy absorption characteristics of bionic crash box are investigated by means of finite element method, and compared with square crash box, diagonal crash box and side-to-side crash box. Under axial impact, the horn-bionic crash box shows significantly better load-carrying and energy-absorbing capacity than the square crash box and the diagonal crash box. On this basis, the thickness parameters, multi-objective optimization design and structure improvement design of horn-bionic crash box are studied successively in this work. The results show that the improved bionic crash box based on horn structure has a typical progressive shrinkage deformation mode. Its SEA reaches 29.9 kJ/kg, which is 2.5 times that of the square crash box, and its PCF is also greatly reduced from 542.4 kN to 391.1 kN. Therefore, the methods of structural improvement such as pre-deformed treatment, constraint beam adjustment and shortening the NPR core can effectively reduce the PCF of the crash box, and improve its energy absorption capacity, so as to obtain better comprehensive crashworthiness. Introducing the key characteristics of the horn structure into the design of the car crash box can effectively improve structural crashworthiness and provide new design guidance for the other energy-absorption components of vehicle.

Influence of Adhesion Properties on the Crash Behavior of Steel/Polymer/Steel Sandwich Crashboxes: An Experimental Study

The energy absorption behavior of crashboxes made of steel/polymer/steel (SPS) sandwich sheets can be influenced by numerous parameters, such as the materials used, their thicknesses and stacking, and the adhesion properties between their layers. Therefore, in the present study, the impact of steel/polymer adhesion quality on the occurring failure modes of the crashboxes and the resulting energy absorptions are experimentally analyzed. For this purpose, axial crushing and three-point bending tests on double-hat and top-hat crash boxes were performed, respectively. Three levels of adhesion quality are investigated: none, weak, and strong adhesion strengths. Additionally, the structural crash properties, such as energy absorption and maximal intrusion, are determined and analyzed at both of the quasi-static and highly dynamic loading rates. The results of these investigations show that the adhesion strengths chosen here significantly influence both the failure modes and the energy absorption values. In particular, the structural parameters, in the case of no adhesion, are at most half of those in the case of strong adhesion. However, it is also shown that, in the case of weak adhesion, the structural characteristics are slightly reduced. Based on these results, the possibility to adjust the adhesion strength—globally and/or locally—could be used in future activities to purposefully tailor the failure behavior of hybrid crashboxes.

Investigation for Crashworthiness Performance of Single-cell and Multi-cell Crash Boxes Designed with Aluminum, Magnesium and Steel Materials

Çarpışma kutuları, olası bir kaza esnasında sürücü ve araç içi yolcularda oluşabilecek yaralanmaları en aza indirmek için kullanılan pasif güvenlik sistemi elemanlarındandır. Araştırmacılar çarpışma kutularının çarpışma performansını iyileştirmek için farklı yapılar ve malzemeler kullanmaktadır. Bu çalışmada alüminyum alaşım AA6061-O, magnezyum alaşım AZ31B ve DP600 çeliğinden tasarlanan kare, altıgen ve dairesel dış duvara sahip tek hücreli ve çok hücreli olmak üzere dokuz farklı çarpışma kutusu sonlu elemanlar analizi ile incelenmiştir. Çalışmada kullanılan sonlu elemanlar modelleri literatürden elde edilen deneysel veriler ile doğrulanmıştır. Farklı malzemelerden tasarlanmış çarpışma kutuları en büyük çarpışma kuvveti, çarpışma kuvveti verimi ve özgül enerji sönümleme kapasiteleri açısından incelenmiştir. İnceleme sonucunda aynı kesite sahip çarpışma kutuları içinde yırtılmalara maruz kalmasına rağmen AZ31B malzemeli modellerin daha yüksek özgül enerji sönümleme kapasitesine sahip olduğu görülmüştür. Ayrıca çok hücreli yapılar tek hücreli yapılara daha iyi çarpışma performansı sergilemiştir.

Application of an inventive problem solving approach for developing new generation vehicle crash boxes

Abstract In frontal crashes, the most important parts that absorb the kinetic energy of the vehicle by plastic deformation are impact absorbers. Efforts are underway to develop innovative impact absorbers to keep the impact of the accident on drivers and passengers to a minimum. The TRIZ (theory of inventive problem solving) approach was used in the product development process of an impact absorber. TRIZ is a creative and systematic problem-solving method that can be used for the development of the next generation of products and systems. TRIZ tools such as ideality, technical contradictions formulation, inventive principles, s-field analysis, and scientific effects were used to achieve ideal final results (IFR). The solutions obtained are evaluated in terms of applicability/ manufacturing, cost, lightweight and patentability. This study generated a new standardized solution in Turkey.

Crashworthiness design and multi-objective optimization of a novel auxetic hierarchical honeycomb crash box

Crashworthiness design and multi-objective optimization of a novel auxetic hierarchical honeycomb crash box

Crash Data Collection System

The increase in the number of fatalities in road accidents, it has become important to know the reasons for the crash and use the retrieved information for further study. The purpose of the project is to develop a crash box that can be installed for diagnosis into the vehicle. It will act as an independent system, which in case of a crash; will record speed, time of accident, and location of the vehicle, for some references. This recorded data will provide valuable information during the post-crash analysis. The device will make use of components like the ATMEGA328P, a GSM module, a rotary encoder, a NEO 6M GPS module & an EEPROM. The data obtained by the device can be used by the vehicle manufacturers to analyze the reason for the crash and to find proper solutions to prevent the same in the future.

The Behavior of Square Crash Box in Various Cross-Section Subjected yy High-Velocity Impact

The application of thin-walled tubes as energy-absorbing equipment has been recognized in various structural systems. The structure absorbs energy by converting kinetic energy to plastic deformation energy. This study will investigate the crash box with several square cross-section ratios about the ability to absorb impact energy.The specimens are made of thin aluminum tubes, 2 mm of thick, 150 mm of length, and the cross-section is a square with 50 mm x 50 mm of size. The size of the square cross-sections is varied by maintaining a fixed circumference. The steel impactor crash into the axial direction specimen by 80 m / s of velocity. The elastic deformation, plastic deformation, and the reaction force occurred due to the collision. The simulation is completed by ANSYS WORKBENCH based on the finite element method.The experiments obtained the maximum deformation, the reaction force, and plastic deformation energy. The square cross-section 50 mm × 50 mm (ratio = 1) the deformation is 49,442 mm. The greater the ratio, the greater the deformation occurs. The reaction force is also getting larger with a larger ratio. On the other hand, the energy absorbed from plastic deformation is getting smaller. It has been agreed that the cross-section ratio = 1 is the best performance of the impact energy absorption.

An experimental and numerical analysis on influence of triggering for composite automotive crash boxes under compressive impact loads

In automobiles there is large scope for composite materials to be used for manufacture of structural parts. The development of electric vehicles has caused for a gain in utilization of composites in automotive applications. In the event of a collision composites afford for an electrical insulation aimed at safety in contradiction of electric shock along with higher strength to weight ratios, which helps in making light weight automobile structures. But composite materials have peculiar as well as complex deformation patterns under compressive impact loading, which is common in vehicle collisions. The deformation pattern of the composites depends on the type of materials used for reinforcement as well as matrix and their layout. Triggers which are accommodated in the design of an element so that deformation initiates at the specific region and has a high impact on the attribute with reference to energy absorption the component as they modify the deformation modes. Therefore before using composite materials for structural parts in automobiles, it is essential to characterize their behaviour when subjected to impacts. For the parts under compressive impact loadings the common method employed for studying the behavior under such conditions is Drop weight impact testing. In this study a GFRP (glass fiber reinforced plastic) composites crash boxes with four different cross sections (square, cylindrical, hexagonal and decagonal) provided with two different triggering patterns (slot trigger and front end trigger) are subjected to drop weight impact testing. In this study, influence of triggering on composite crash box is investigated using experimental drop weight testing along with correlation of numerical simulation. The prime motive of this study is to illustrate the influence of triggers on the deformation pattern along with the force and energy absorption level for a GFRP crash boxes under drop weight axial impacts.

Conversion of Aluminum Front Bumper System to Magnesium Material by Using Design of Experiment Method

Bumper and crash boxes are vehicle structural elements that convert the collision (kinetic) energy at the collision into deformation energy. Failure of the bumper system to sufficiently absorb the collision energy in the event of a collision will result in the resulting forces being transferred directly to the driver and passenger area. It will result in deaths or injuries to people in the vehicle and further damage to the vehicle. In this study, the collision performance of an existing aluminum crash bumper system produced by the extrusion method with a 40% offset collision analysis is examined. A magnesium crash bumper with improved collision performance is designed by this reference. In this design process, the design of experiment method is used. With the combinations created with the Taguchi method, the long design and analysis process is completed in a shorter time. Taguchi experiment design process; four different design variables and three-level combinations of these variables are used. With the table's help created at the L9 level, models corresponding to the variables are prepared, crash analyzes are performed with finite element analysis, and crash performances are examined. After revealing the results, optimization is carried out with Minitab software; the optimum design is achieved in crash performance and lightness.

Multi-Segment Crash Box Energy Absorption Ability Using Computer Simulation

Crash box is one of the passive safety components in vehicles, especially cars that are designed to reduce the occurrence of injuries to drivers and passengers due to collisions. This study aims to determine the energy absorption of the crash box with a multi-segment circular cross section. The research method used is quasi-experimental, namely by computer simulation using Finite Element Method-based software. The independent variable in this study is the location of the segment connection, including: 1/4, 1/3, and 1/2 of the total length of the crash box. While the dependent variables that are sought include: energy absorption, force reaction, and deformation patterns that occur in the crash box. The crash box will be hit by an impactor with a mass of 103 kg and a speed of 7.67 m/s. From the simulation results, the maximum energy absorption and force reaction values are found in the crash box at connection 1/2 of 1689.7 J and 67718 N, followed by connection 1/3 with values of 1221.2 J and 56127 N, and the last is at 1/4 connection is 1119.8 J and 55443 N. Judging from the deformation pattern, the connection at 1/4 and 1/3 is buckling so that the energy absorption is lower than the crash box at the 1/2 connection. It is concluded that the most optimal design of the crash box with a multi-segment circular cross section is the model at the 1/2 connection because it has the highest energy absorption value of the other 2 models and the deformation tends to be more stable.

Multi-objective optimization of crash box filled with three-dimensional cellular structure under multi-angle impact loading

Oblique impact loading conditions are common in automobile collision accidents, which strongly influence the energy absorption performance of thin-walled structures. In this paper, a novel three-dimensional (3-D) hexagonal structure-filled crash box with better comprehensive crashworthiness under multiple working conditions is proposed. First, the finite element models of four 3-D typical cellular structures (hexagon structure, re-entrant hexagon structure, star-shape structure, double arrow structure) are established. The dynamic responses of four structures under different impact angles (from 0° to 30°) and impact velocities (from 5 to 15 m/s) are discussed. The results reveal that the 3-D hexagonal structure has great advantages in terms of the energy absorption at varying inclination angles. Second, the 3-D hexagonal structure is filled in the crash box in the form of gradient distribution. The multi-island genetic algorithm (MIGA) based on the response surface model (RSM) is utilized to explore the optimal design of crash box. Compared with the traditional crash box, the optimal 3-D hexagonal structure-filled crash box increases 18.9% in specific energy absorption and decreases 21.7% in maximum peak force, which demonstrates great potential for applications in impact engineering.

A basic design for automotive crash boxes using an efficient corrugated conical tube

Frontal vehicle structure is of high importance through crash energy managements and crash boxes are the fundamental structural component for vehicle safety as well as after sales issues. Similar to many other vehicle components, the detail design of crash box is usually part of manufacture knowhow. However, some guide lines are always available. In this article a general procedure is introduced for designing of crash box with the aid of novel thin walled structures and according to conventional crash scenarios. The problem is followed through some basic steps. Firstly, the crash box idea is selected through a wide range of previous investigated elements and is packaged in a real bench vehicle. Then thanks to the protection provided by the new crash box on the other more expensive components (e.g. headlamp, cooling pack, etc.), the effectiveness of this element are acknowledged through the low speed offset crash. Further on the robustness of new proposed crash box is approved by high speed crash simulations. The quasi-static simulations implemented during the analyses are carried out by finite element explicit code (Abaqus) and the FE modeling and dynamic simulation through the next steps are also performed in ANSA and PAM CRASH respectively. Finally in addition to the general crash box design proposed procedure, the achieved results demonstrated that the corrugated conical thin walled tubes deforms in regular and rather stable shape under both axial and oblique loadings. They also produced a reasonable reaction force versus deformations which leads to stiff and crashworthy energy absorber in comparison to traditional rectangular and even some special models like as origami shapes, and so they could be a valuable selection for crash box implementations in passenger cars.

Deformation pattern and energy absorption of polylactic acid (PLA) carbon crash box under quasi static loading

The purpose of this study is to investigate the deformation pattern and of energy absorption (EA) in Polylactic Acid Carbon Crash Box. The crash box specimen was produced by using 3D printer machine. The quasi static testing method is performed to compress the specimen with a speed of 2 mm min−1 using universal testing machine. It was pressed until it reaches deformation of 80 mm from its original length of 120 mm. The deformation was analyzed in three different variations of wall thickness (Wt), 1.6 mm; 1.8 mm; and 2 mm. The deformation pattern and the maximum EA are analyzed to determine the best design specifications. The results show that the highest EA occurs on Wt 2 mm (357.986 J), whereas the lowest EA occurs on Wt 1.6 mm (224.012 J). The local buckling and discontinue folding consist on three model of crash box. In addition, the fragmentation is also formed on Wt 2 mm of crash box but it is not looked on remain models.

Study of modal properties and crashworthiness performance of crash box numerical model with different joining modelling strategies

It is important to understand the natural frequencies and the mode shapes for automotive structure such as crash box as it will be subjected to the dynamic loading in its real application. In addition, it is also important to study other dynamic behaviour such as crash and buckling as crash box is one of energy absorbing member that is intended for car safety during collision. In this study, modal properties of three different crash box models joint by three different joint modelling strategies and also their crash and buckling behaviour was analysed and investigated. Computational frequency analysis, dynamic crash analysis and nonlinear buckling analysis was performed on all of crash box models. the crash box modelled with node equivalent method to represent the welded joint shows higher stiffness at the joining area and therefore shows higher value of natural frequencies that the model with CBEAM and CBAR elements as their joining elements. In term of crash behaviour, the model with CBEAM element shows higher reaction force compared to the CBEAM. This proves that different type of joint modelling strategies behaves differently.

Energy absorption and deformation pattern analysis of carbon fibre reinforced composite crash box under frontal load model

Crash boxes as a passive safety system in vehicles had been developed to produce high energy absorption performance. This study investigates the influence of cross-section geometry and fibre orientation angle on the composite crash box design to determine deformation pattern and energy absorption performance. The cross sections studied are circles and squares with variations in fibre orientation angles 0°, 15°, 30°, 45°, 60° and 75°. Carbon Fibre Epoxy CFS003 / LTM25 Prepegs with the type of plain woven fibre used to model crashbox structures. The computer simulation test model was carried out using a frontal load model with velocity of 7.76 m s−1. The results showed a circle cross-section at each variation of the orientation angle has a higher energy absorption than a square cross-section. Deformation patterns in each model show different characteristics including fragmentation mode, lamina bending, brittle fracturing, and local buckling as well as a combination of several patterns. The highest energy absorption obtained in the C60 model was 3.664 kJ with Specific Energy Absorption (SEA) of 36.799 kJ kg−1 and a CFE value of 0.59. While the lowest energy absorption occurs in the S45 model with 1.287 kJ which has a SEA value of 12.667 kJ kg−1with a CFE of 0.49. The CFE value indicates that the model with a circular cross section has better crushing stability than a squarecross section.

Energy Absorption Characteristics of Crash Box of New Honeycomb Core Structure with Foam-Filled

By combining honeycomb core with the traditional crash box, an innovative foam-filled honeycomb core structure crash box is proposed to improve safety performances. Three kinds of honeycomb core crash boxes were obtained by filling the inside of the traditional crash box with the quasi-honeycomb core, the quasi-square honeycomb core and hexagonal honeycomb core. It is deduced that the energy absorption of the quasi-honeycomb core crash box increased by 42.2 %, the peak of the collision force reduced by 8.9 %. The hexagonal honeycomb core crash box and the quasi-square honeycomb core crash box also enhance the energy absorption characteristics, but the peak impact force increased by 5.6 % and 9.6 %. After filling of the Expanded Polypropylene (EPP) foam, the peak collision force of the EPP hexagonal honeycomb core crash box and the EPP quasi-square honeycomb core crash box increased by 10 %, while Fmax of the EPP quasi-honeycomb core crash box reduced by 2.3 % and the energy absorption increased by 54.6 %. Six structures were compared to highlight the energy absorption characteristics of the filling the inside of the traditional crash box with the light in weight honeycomb core and EPP foam. The research results provide a new idea for the design of crash box.

Material Model Development of Magnesium Alloy and Its Strength Evaluation.

A new material model of magnesium alloys, combining both Hill’48 yield function and Cazacu’06 yield function, was developed and programmed into LS-DYNA using user subroutine, in which both slip dominant and twinning/untwinning dominant hardening phenomena were included. First, a cyclic load test was performed, and its finite element analysis was carried out to verify the new material model. Then, the deformation behaviors of the magnesium crash box subjected to the compressive impact loading were investigated using the developed material model. Compared with the experimental results, the new material model accurately predicted the deformation characteristics of magnesium alloy parts. Additionally, the effect of the thickness distribution, initial deflection and contact friction coefficient in simulation models on deformation behaviors were investigated using this validated material model.

Dynamic Buckling of Crash Boxes Under Impact Load

Buckling stress is an important design factor in crash box (CB) design. However due to the dynamic nature of the impact defining the exact buckling point is a challenge. In this research experimental drop tower test has been performed on CBes. Finite element (FE) simulation of the CB is performed using Abaqus and the FE model is validated by experimental test results. Some hints for simulating and validating the FE model are provided. The Structural behavior of the CB under impact load has been investigated. In order to define buckling initiation point on the FE model a new approach, named integration points criterion, has been introduced.

Examination for Improving Energy Absorption Performance of Crash Box Consisting Cells with Hole

Examination for Improving Energy Absorption Performance of Crash Box Consisting Cells with Hole

Design optimization of passenger SUV’s crash box and bumper beam by using finite element method

The accident cases with front crash type occupy the largest data statistics with 7,372 cases. Theoretically, the accident cases which involve passenger cars, kinetic energy is absorbed by the complex system. Some components which are included in the system are crash box and bumper beam. The main purpose of this research is to obtain the absorption of kinetic energy when the accident happened, types of deformation, and optimization in the existing designs of crash box and bumper beam from vehicle unit. Finite element method combines with analytical value are used in the simulation. Whereas, the software used in solid modelling is SolidWork and the numerical analysis used in this research is Abaqus / Explicit. The average reaction force through simulation is obtained by averaging the results of curve plotting, while the average reaction force is obtained through formula analysis by taking material property and dimension data and then inputting it in the calculation. From the simulation, energy absorbed is 9,912 Joule from the whole original structure. The energy absorbed is less than the crash box work which is 14,066 Joule within an error value of 22 %. This is caused by the bending moment which is emerged by bumper beam. Then, optimization is done by increasing lateral lengths of bumper beam with 20 mm, 15 mm and 10 mm, therefore energy absorption increased with 20,362 Joule, 31,886 Joule and 16,348 Joule, respectively.