Composite Core Cross Tube Crushing Analysis

Author(s):  
Sean Jenson ◽  
Muhammad Ali ◽  
Khairul Alam

Abstract Thin walled axial members are typically used in automobiles’ side and front chassis to improve crashworthiness of vehicles. Extensive work has been done in exploring energy absorbing characteristics of thin walled structural members under axial compressive loading. The present study is a continuation of the work presented earlier on evaluating the effects of inclusion of functionally graded cellular structures in thin walled members under axial compressive loading. A compact functionally graded composite cellular core was introduced inside a cross tube with side length and wall thickness of 25.4 mm and 3.048 mm, respectively. The parameters governing the energy absorbing characteristics such as deformation or collapsing modes, crushing/ reactive force, plateau stress level, and energy curves, were evaluated. The results showed that the inclusion of composite graded cellular structure increased the energy absorption capacity of the cross tube significantly. The composite graded structure underwent progressive stepwise, layer by layer, crushing mode and provided lateral stability to the cross tube thus delaying local tube wall collapse and promoting large localized folds on the tube’s periphery as compared to highly localized and compact deformation modes that were observed in the empty cross tube under axial compressive loading. The variation in deformation mode resulted in enhanced stiffness of the composite structure, and therefore, high energy absorption by the structure. This aspect has a potential to be exploited to improve the crashworthiness of automobile structures.

Author(s):  
Muhammad Ali ◽  
Khairul Alam ◽  
Eboreime Ohioma

Thin walled axial members are typically used in vehicles’ side and front chassis to improve crashworthiness. Extensive work has been done in exploring energy absorbing characteristics of thin walled structural members under axial compressive loading. The present study is a continuation of the work presented earlier on evaluating the effects of presence of functionally graded cellular structures in thin walled members. A functionally graded aluminum cellular core in compact form was placed inside a steel square tube. The crushing behavior was modeled using ABAQUS/Explicit module. The variables affecting the energy absorbing characteristics, for example, deformation or collapsing modes, crushing/ reactive force, plateau stress level, and energy curves, were studied. An approximate 35% increase in the energy absorption capacity of steel tube was observed by adding aluminum graded cellular structure to the square tube. The aluminum graded structure crushed systematically in a layered manner and its presence as core supported the steel square tube side walls in transverse direction and postponed the local (tube) wall collapse. This resulted in composite tube undergoing larger localized folds as compared to highly compact localized folds, which appeared in the steel tube without any graded core. The variation in deformation mode resulted in increased stiffness of the composite structure, and therefore, high energy absorption by the structure. Further, a relatively constant crushing force was observed in the composite tube promoting lower impulse. This aspect has a potential to be exploited to improve the crashworthiness of automobile structures.


Author(s):  
Zhichao Li ◽  
Subhash Rakheja ◽  
Wen-Bin Shangguan

Thin-walled structures are widely used as energy absorbers in automotive vehicles due to their lightweight and high-energy absorption efficiency. In order to improve the energy absorption characteristics of thin-walled structures subjected to different loading angles, different types of novel multi-cell structures are proposed in this paper. The numerical method is used to study the crushing behaviors of the proposed multi-cell structures under different loading angles. It is found that the proposed multi-cell structures have considerably small initial peak force under axial load and avoid the appearance of global buckling deformation mode under oblique loads. Moreover, reasonably distributed wall thickness for each square tube in the thin-walled structure can enhance its energy absorption capacity under different loading angles.


Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4304
Author(s):  
Miroslaw Ferdynus ◽  
Patryk Rozylo ◽  
Michal Rogala

The paper presents the results of numerical tests of impact and energy absorption capacity of thin-walled columns, subjected to axial impact loading, made of aluminum alloy, and having a square cross-section and spherical indentations on their lateral surfaces. The numerical models were validated using an experiment that was conducted on the Instron CEAST 9350 High Energy System drop hammer. Material properties of the applied aluminum alloy were determined on the basis of a static tension test. The crushing behavior of the columns and some crashworthiness indicators were investigated. On the basis of the results of the conducted analyses, conclusions were drawn about the most beneficial design/constructional variants in terms of achieved crashworthiness parameters.


Author(s):  
Sean Jenson ◽  
Eboreime Ohioma ◽  
Muhammad Ali ◽  
Khairul Alam

Abstract Thin wall structures are primarily deployed in automotive chassis to increase the energy absorption capacity of the automobiles in the event of an accident. Researchers have delved into developing lighter structures for improving automobiles’ fuel efficiency with a challenge of maintaining or preferably exceeding the energy absorption properties of the structure. In this study, the work presented is a continuation of research conducted on exploring the effects of the introduction of cellular core in tubular structures under axial compressive loading. The crushing response of cellular core cross tube was numerically studied using ABAQUS/Explicit module. The characteristics such as deformation or collapsing modes, crushing/ reactive force, locking strain, energy curves, and specific energy absorbed were studied. The cellular core cross tube shows significant potential for reducing the weight of automobile structure while giving positive indication towards enhancing the specific energy absorption capacity.


2013 ◽  
Vol 437 ◽  
pp. 158-163
Author(s):  
Wei Liang Dai ◽  
Xu Guang Li ◽  
Qing Chun Wang

Energy absorbing characteristics of the non-stiffened and stiffened single hat sections subjected to quasi-static axial crushing were experimentally investigated. First non-stiffened hat sections were axially crushed, then structures with different stiffened methods (stiffened in hat and stiffened in the plate) were tested, finally energy absorption capacities of these structures were compared. Test results showed that, for the appropriate designed stiffened tube, the mean crush force and mass specific energy absorption were increased significantly compared to the non-stiffened. Stiffened in hat section showed a little more energy absorption capacity than that stiffened in the plate, but the structure may sustain a global bending.


2019 ◽  
Vol 11 (1) ◽  
pp. 41-68 ◽  
Author(s):  
Chukwuemeke William Isaac

The dynamic oblique crushing of circular thin-walled tubes with the presence of non-propagating crack was investigated numerically. The material considered was strain rate sensitive with crack located at the distal end of the tube. Major crashworthiness parameters were obtained and the analysis of the structural response for idealized and finite element crushed thin-walled tubes was also carried out. The study shows that crack initiation on energy absorbing tubes increase their crushing force efficiency under oblique impact, decrease their crushing force efficiency under axial impact and reduce their crashworthiness performance such as the energy absorption capacity and specific energy absorption under axial and oblique impact. Results of the crashworthiness parameters, deformation modes, damage morphology, stress–strain relations, absorption energy characteristics and crushing force-displacement history were obtained. Furthermore, the numerical study reveals both the desirable and undesirable consequence of crack on the overall crashworthiness performance of energy absorbing circular thin-walled tubes.


Author(s):  
Muhammad Ali ◽  
Eboreime Ohioma ◽  
Khairul Alam

Square tubes are primarily used in automotive structures to absorb energy in the event of an accident. The energy absorption capacity of these structural members depends on several parameters such as tube material, wall thickness, axial length, deformation modes, locking strain, crushing stress, etc. In this paper, the work presented is a continuation of research conducted on exploring the effects of the introduction of cellular core in tubular structures under axial compressive loading. Here, the crushing response of composite cellular core tube was numerically studied using ABAQUS/Explicit module. The energy absorbing characteristics such as deformation or collapsing modes, crushing/ reactive force, crushing stroke, and energy curves were discussed. The composite cellular core tube shows promise for improving the crashworthiness of automobiles.


Author(s):  
Muhammad Ali ◽  
Khairul Alam ◽  
Eboreime Ohioma

Axial members are commonly used in automotive structures and are responsible for absorbing significant portion of impact energy in the event of an accident. This study was conducted to investigate the effects of inclusion of functionally graded cellular structures in thin walled members under compressive axial loading. A compact functionally graded cellular structure was introduced inside a 352 mm long square tube with side length and wall thickness of 74 mm and 3.048 mm, respectively. The tube wall material was aluminum. The cellular structure’s geometry was observed in the cross-section of a banana peel that has a specific graded cellular packing in a confined space. This packing enables the peel to protect the internal soft core from external impacts. The same cellular pattern was used to construct the structure in present study. The study was conducted using non-linear finite element analysis in ABAQUS. The hybrid structure (tube and graded cellular structure) was fixed on one side and on the other (free end) side, was struck by a rigid mass of 300 Kg travelling at a velocity of 35 mph (15.64 m/s) along the axis of the square tube and perpendicular to the in-plane direction of the graded cellular structure. The tube and cell walls were discretized using reduced integration, hourglass control, 4 nodes, and hexahedral shell elements. The impact plate was modeled with 4 node rigid shell elements. General contact conditions were applied to define surface interaction among graded structure, square tube, and rigid plate. The parameters governing the energy absorbing characteristics such as deformation or collapsing modes, crushing/ reactive force, and energy curves, were evaluated. The results showed that the inclusion of graded cellular structure increased the energy absorption capacity of the square tube by 41.06%. The graded structure underwent progressive stepwise, layer by layer, crushing mode and provided lateral stability to the square tube thus delaying local tube wall collapse and promoting outward convex localized folds on the tube’s periphery as compared to highly localized and compact deformation modes that are typically observed in an empty square tube under axial compressive loading. The variation in deformation mode, large contact areas, presence of graded cellular structure resulted in enhanced stiffness of the hybrid structure, and therefore, high energy absorption by the structure. The results of this preliminary study show a potential of functionally graded cellular materials to significantly improve the energy absorbing capacities of thin walled members under axial loading by altering member’s crushing deformation modes.


The aim of this study is to examine the effect of fiber mat’s density and deformation mechanism of tubes with and without die compression. In this study a new mode of deformation mechanism of density graded GFRP circular tube is examined when they are subjected to axial compression on to a die and without die to examine its energy absorbing capacity. Theoretical calculations were made to predict the crushing stress of different specimens. It is observed that increasing density of fiber increases energy absorption value but decreases the specific energy absorption and the die could trigger progressive crushing additionally decreasing peak load. Here the compressed tube wall is compelled to be deformed towards the end of compression die with a little range of bending curvature which was forced by the radius of the die at high crushing stress and the major part of the deformation takes place at a nearly constant load, which leads to high energy absorption capacity. Comparison between theoretical prediction values by derived equations and the experimental results shows good correlation.


Author(s):  
D. Tankara ◽  
R. Moradi ◽  
Y. Y. Tay ◽  
H. M. Lankarani

Over the past few decades, much research work has been conducted on the development of advance crashworthy structures to increase the energy absorption of mechanical systems. Thin-walled tubes are primarily used as structural reinforcements and as energy absorbing components. The high-energy absorption characteristics of cellular foams have attracted great attention to further enhance this superior capability. In particular, nanotechnology has been utilized in the development of advanced cellular materials for the automotive and aerospace industry. The primary objective of this study is to conduct a parametric study using experimental and finite element methods to examine and quantify the performances of thin-walled tube when filled with carbon nano particulates. To accomplish this study, compression tests are carried out to obtain the load-deflection curves of the nano-foams when subjected to different weight percentages of carbon nano fibers. Next, the specific energy absorbed and the collapse mechanism of nano foam filled thin-walled tubes are analyzed and compared with the empty ones. Finally, an illustrative study on the use of nano foams for vehicular applications is presented by using a vehicle bumper numerical model. The carbon nano foam is installed into the cavity of the bumper model and a full-frontal crash simulation is performed. Overall, this study has shown that the energy absorption capacity of thin-walled structures can be significantly enhanced with the use of carbon nano foams.


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