scholarly journals Deformation and energy absorption of additively manufactured functionally graded thickness thin-walled circular tubes under lateral crushing

2021 ◽  
Vol 226 ◽  
pp. 111324 ◽  
Author(s):  
Ahmad Baroutaji ◽  
Arun Arjunan ◽  
Mark Stanford ◽  
John Robinson ◽  
Abdul Ghani Olabi
Keyword(s):  
Energy Absorption ◽  
Functionally Graded ◽  
Circular Tubes ◽  
Thin Walled ◽  
Graded Thickness

Multi-Objective Optimization Design of Functionally Graded Foam-Filled Graded-Thickness Tube Under Lateral Impact

2018 ◽  
Vol 16 (01) ◽  
pp. 1850088 ◽  
Author(s):  
Hanfeng Yin ◽  
Jinle Dai ◽  
Guilin Wen ◽  
Wanyi Tian ◽  
Qiankun Wu
Keyword(s):  
Energy Absorption ◽  
Wall Thickness ◽  
Functionally Graded ◽  
Design Parameters ◽  
Foam Density ◽  
Lateral Impact ◽  
Multi Objective Optimization ◽  
Foam Filled ◽  
Thin Walled ◽  
Graded Thickness

Foam-filled thin-walled structure has been widely used in vehicle engineering due to its highly efficient energy absorption capacity and lightweight. Unlike the existing foam-filled thin-walled structures, a new foam-filled structure, i.e., functionally graded foam-filled graded-thickness tube (FGFGT), which had graded foam density along the transverse direction and graded wall thickness along the longitudinal direction, was first studied in this paper. Two FGFGTs with different gradient distributions subjected to lateral impact were investigated using nonlinear finite element code through LS-DYNA. According to the parametric sensitivity analysis, we found that the two design parameters [Formula: see text] and [Formula: see text], which controlled the gradient distributions of the foam density and the tube wall thickness, significantly affected the crashworthiness of the two FGFGTs. In order to seek for the optimal design parameters, two FGFGTs were both optimized using a meta-model-based multi-objective optimization method which employed the Kriging modeling technique as well as the nondominated sorting genetic algorithm II. In the optimization process, we aimed to improve the specific energy absorption and to reduce the peak crushing force simultaneously. The optimization results showed that the FGFGT had even better crashworthiness than the traditional uniform foam-filled tube with the same weight. Moreover, the graded wall thickness and graded foam density can make the design of the FGFGT flexible. Due to these advantages, the FGFGT was an excellent energy absorber and had potential use as the side impact absorber in vehicle body.

Composite Core Cross Tube Crushing Analysis

2020 ◽  
Author(s):  
Sean Jenson ◽  
Muhammad Ali ◽  
Khairul Alam
Keyword(s):  
Energy Absorption ◽  
Compressive Loading ◽  
Deformation Mode ◽  
High Energy ◽  
Absorption Capacity ◽  
Functionally Graded ◽  
Layer By Layer ◽  
Thin Walled ◽  
The Cross ◽  
Energy Absorbing

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.

Multiple objective crashworthiness optimization of circular tubes with functionally graded thickness via artificial neural networks and genetic algorithms

2016 ◽  
Vol 231 (11) ◽  
pp. 2005-2016 ◽  
Author(s):  
Adil Baykasoğlu ◽  
Cengiz Baykasoğlu
Keyword(s):  
Neural Networks ◽  
Genetic Algorithms ◽  
Artificial Neural Networks ◽  
Functionally Graded ◽  
Design Parameters ◽  
Multiple Objective ◽  
Circular Tubes ◽  
Crashworthiness Optimization ◽  
Artificial Neural ◽  
Graded Thickness

The objective of this paper is to develop a multiple objective optimization procedure for crashworthiness optimization of circular tubes having functionally graded thickness. The proposed optimization approach is based on finite element analyses for construction of sample design space and verification; artificial neural networks for predicting objective functions values (peak crash force and specific energy absorption) for design parameters; and genetic algorithms for generating design parameters alternatives and determining optimal combination of them. The proposed approach seaminglesly integrates artificial neural networks and genetic algorithms. Artificial neural network acts as an objective function evaluator within the multiple objective genetic algorithms. We have shown that the proposed approach is able to generate Pareto optimal designs which are in a very good agreement with the finite element results.

Energy Absorption of Axial Members With the Inclusion of Functionally Graded Cellular Structure

2015 ◽  
Author(s):  
Muhammad Ali ◽  
Khairul Alam ◽  
Eboreime Ohioma
Keyword(s):  
Energy Absorption ◽  
Cellular Structure ◽  
Tube Wall ◽  
Axial Loading ◽  
Hybrid Structure ◽  
Functionally Graded ◽  
Shell Elements ◽  
Thin Walled ◽  
Energy Absorbing ◽  
Deformation Modes

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.

Axially Loaded Pressurized Thin-Walled Circular Tubes Used as Adaptive Energy Absorbers

2008 ◽  
Author(s):  
X. W. Zhang ◽  
T. X. Yu
Keyword(s):  
Internal Pressure ◽  
Energy Absorption ◽  
Applied Pressure ◽  
Deformation Mode ◽  
Mode I ◽  
Mode Ii ◽  
Circular Tubes ◽  
Thin Walled Structures ◽  
Ring Mode ◽  
Thin Walled

By filling compressed air into cellular materials, honeycombs or thin-walled structures, their energy absorption can be greatly enhanced, while this enhancement can be controlled by the applied pressure. This concept shines a light on the possibility of achieving adaptive energy absorption. To investigate the effect of the internal pressure on the response of the structures under impact loadings, the present paper reports our study on the axial crushing behavior of pressurized thin-walled circular tubes. Three groups of thin-walled circular tubes with the radius/thickness ratio between 120 and 200 were employed in the experiments and two working modes were studied: mode-I (with constant internal pressure) and mode-II (closed tubes with finite leakage). In the tests of mode-I, the influences of internal pressure on the deformation mode and energy absorption of the tubes were investigated. The results show that with the increase of internal pressure, the deformation mode switches from diamond mode with sharp corners to that with round corners, and eventually to ring mode. In diamond mode, the mean force of the tubes increases linearly with the internal pressure. The enhancement comes from two mechanisms: direct effect of the pressure and indirect effect due to the interaction between the pressure and the tube wall. After the deformation switches to ring mode, the enhancement resulted from the second mechanism becomes weaker. Based on the results of mode-I, the mode-II was experimentally investigated both quasi-statically and dynamically. The results are compared with the predictions obtained from a semi-empirical formula, showing good agreements.

Sign in / Sign up

Export Citation Format

Share Document