scholarly journals Effects of Geometry, Triggering and Foam-Filling on Crashworthiness Behaviour of a Cylindrical Composite Crash Box

2019 ◽  
Vol 16 (2) ◽  
pp. 6568-6587
Author(s):  
M. Jahani ◽  
H. Beheshti ◽  
M. Heidari-Rarani
Keyword(s):  
Energy Absorption ◽  
Failure Modes ◽  
Maximum Load ◽  
Polymeric Foam ◽  
Damage Initiation ◽  
Finite Element Software ◽  
Complementary Role ◽  
Foam Filling ◽  
Energy Absorbers ◽  
Crash Behaviour

Crash boxes play an important role in different industries as energy absorbers to reduce damage of accidents. An ideal crash box has lower maximum force and higher energy absorption. The aim of this study is to investigate the effect of various parameters such as geometry (diameter and thickness), triggering and filling with polymeric foam on axial crash behaviour of a composite cylindrical cash box. To this end, a composite crash box is modelled in a commercial finite element software, Abaqus, utilising the Hashin failure criterion to predict damage initiation. Linking damage initiation with material degradation rules provides the capability for damage evolution prediction on the basis of fracture energy of different failure modes. A new parameter (β) is defined to study the performance of a crash box with different geometries, triggers and foam-filling. The results show that three different triggering geometries (chamfer, fillet, and tulip) decrease the maximum load about 7-33%, and improved energy absorption about 40-86% compared to the crash box without trigger. Filling a triggered crash box with polymeric foam also improves energy absorption about 20%. Applying both triggering and foam-filling simultaneously on a crash box has a complementary role to receive a better performance.

scholarly journals Bending Response and Energy Absorption of Closed-Hat-Section Beams

2016 ◽  
Vol 10 (11) ◽  
pp. 225
Author(s):  
Hafizan Hashim ◽  
Amir Radzi Ab Ghani ◽  
Wahyu Kuntjoro
Keyword(s):  
Energy Absorption ◽  
Plate Thickness ◽  
Point Of View ◽  
Critical Parameters ◽  
Research Report ◽  
Experimental Point ◽  
Fe Model ◽  
Research Information ◽  
Foam Filling ◽  
Energy Absorbers

Many articles on bending collapse but not limited to closed-hat-section beams have been reported mainly from experimental point of view but less in simulation-based approach. Detailed investigation on critical parameters of closed-hat-section beams to examine their energy absorption capability is also less found in the literature. This paper presents the procedure for development and validation of a finite element (FE) model of a closed-hat-section beam under quasi static three-point bending using an explicit nonlinear FE technique. Developed FE models were validated through comparison with existing and present experiment results. Firstly, the existing models were rebulit via present modeling technique using informations provided in the relevant research report. Simulation results of rebuilt model were compared with existing results for verification and validation. Next, to further validate the present model, actual physical experiment replicating the FE model was set up for comparison of results. Validated models were then used in parametric studies in order to investigate the effect of some critical parameters such as plate thickness, flange and web width, and foam filler. Results show that the wall thickness, web width, and filler have direct effect on bending stiffness. Foam filling indicated significant enhancement on the crush and energy absorption of closed-hat-section beams. This study provides detail procedures and research information which will facilitate improvisation of current design as well as the design of foam filled closed-hat-section beams as energy absorbers in impact applications.

Axial Compression and Energy Absorption Characteristics of Reduction Tubes Using a Die under Impact Load

2013 ◽  
Vol 712-715 ◽  
pp. 1519-1526 ◽  
Author(s):  
He Mao ◽  
Kai He ◽  
Chang Jie Luo ◽  
Ru Xu Du
Keyword(s):  
Energy Absorption ◽  
Axial Compression ◽  
Impact Load ◽  
Numerical Study ◽  
Expansion Tube ◽  
Finite Element Software ◽  
Study Results ◽  
Energy Absorbers ◽  
The Relationship ◽  
Absorption Characteristics

Reduction tube using a die is a kind of deformation tubes which are used on railway train as energy absorbers. In this paper, axial compression behavior and energy absorption characteristics of reduction tubes using a die under impact load are investigated. No-linear finite element software LS-DYNA is used to conduct the numerical study. Results for the expansion tube using a die (another kind of deformation tube) and the reduction tube using a die are compared. Assuming two different structures with the same material and sectional area, an analysis shows that the energy absorption of reduction tube is better than the expansion tube. Hence, the reduction tubes using a die are investigated using a series of numerical analysis. The relationship between displacement and load, average load are obtained. The influences of impact mass and impact velocity are discussed.

The Indentation Behaviour of Carbon Fibre Composite Tubes-Experiments & Modelling

2010 ◽  
Vol 654-656 ◽  
pp. 2616-2619
Author(s):  
Ranjani Sudharsan ◽  
Bernard F. Rolfe ◽  
Peter D. Hodgson
Keyword(s):  
Finite Element ◽  
Carbon Fibre ◽  
Energy Absorption ◽  
Side Impact ◽  
Cyclic Shear ◽  
Finite Element Software ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Cfrp Tubes ◽  
Crash Behaviour

Metallic tubes have been extensively studied for their crashworthiness as they closely resemble automotive crash rails. Recently, the demand to produce lighter weight, yet safer vehicles has led to the need to understand the crash behaviour of novel materials, such as fibre reinforced polymer composites, metallic foams and sandwich structures. This paper discusses the static indentation response of Carbon Fibre Reinforced Polymer (CFRP) tubes. The side impact on a CFRP tube involves various failure mechanisms. This paper highlights these mechanisms and compares the energy absorption of CFRP tubes with similar Aluminium tubes. The response of the CFRP tubes during bending was modelled using ABAQUS finite element software with a composite fabric material model. The material inputs were given based on standard tension and compression test results and the in-plane damage was defined based on cyclic shear tests. The failure modes and energy absorption observed during the tests were well represented by the finite element model.

scholarly journals Study on delamination damage evolution of composite L-shaped adhesive joint based on cohesive behavior

2021 ◽  
Vol 39 (2) ◽  
pp. 309-316
Author(s):  
Hongliang Tuo ◽  
Zhixian Lu ◽  
Xiaoping Ma ◽  
Hongyu Guo
Keyword(s):  
Adhesive Joint ◽  
Damage Evolution ◽  
Failure Modes ◽  
Numerical Models ◽  
Constitutive Models ◽  
Fatigue Tests ◽  
Adhesive Joints ◽  
Damage Initiation ◽  
Finite Element Software ◽  
Delamination Damage

The adhesive joint of composite materials is one of the typical structures in aircraft structures, and the delamination damage is one of the most important damage modes in composite adhesive joints. In this paper, static and fatigue tests were carried out on L-shaped adhesive joints to analyze the damage evolution and failure modes of delamination damage under static and fatigue loadings. Based on the cohesive constitutive models, the static and high-cycle fatigue delamination constitutive models were developed. The static and fatigue numerical models of composite L-shaped adhesive joints were established by using finite element software. The stress distribution, deformation modes and delamination propagation laws were systematically studied. The simulation results are in good agreement with the experimental results. The delamination damage initiation, evolution and failure mechanism of L-shaped adhesive joints under static and fatigue loads were revealed by combining the experimental and the numerical results, which will provide theoretical and engineering guidance for strength and fatigue analysis of composite adhesive structures.

scholarly journals Evaluation of Energy Absorption Capabilities of Polyethylene Foam under Impact Deformation

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3613
Author(s):  
Baohui Yang ◽  
Yangjie Zuo ◽  
Zhengping Chang
Keyword(s):  
Energy Absorption ◽  
Failure Modes ◽  
High Strain ◽  
Early Stage ◽  
High Energy ◽  
Test Method ◽  
Test Theory ◽  
Strain Rates ◽  
Impact Properties ◽  
The Impact

Foams are widely used in protective applications requiring high energy absorption under impact, and evaluating impact properties of foams is vital. Therefore, a novel test method based on a shock tube was developed to investigate the impact properties of closed-cell polyethylene (PE) foams at strain rates over 6000 s−1, and the test theory is presented. Based on the test method, the failure progress and final failure modes of PE foams are discussed. Moreover, energy absorption capabilities of PE foams were assessed under both quasi-static and high strain rate loading conditions. The results showed that the foam exhibited a nonuniform deformation along the specimen length under high strain rates. The energy absorption rate of PE foam increased with the increasing of strain rates. The specimen energy absorption varied linearly in the early stage and then increased rapidly, corresponding to a uniform compression process. However, in the shock wave deformation process, the energy absorption capacity of the foam maintained a good stability and exhibited the best energy absorption state when the speed was higher than 26 m/s. This stable energy absorption state disappeared until the speed was lower than 1.3 m/s. The loading speed exhibited an obvious influence on energy density.

Crashworthiness Optimization of Thin Walled Cylindrical Tubes with Annular Grooves under Axial Compression

2012 ◽  
Vol 463-464 ◽  
pp. 30-35 ◽  
Author(s):  
Reza Emami ◽  
Elahe Sadat Alavi Moghadam ◽  
Mostafa Sohrabi
Keyword(s):  
Maximum Load ◽  
Absorbed Energy ◽  
Optimal Point ◽  
Composite Function ◽  
Explicit Finite Element ◽  
Cylindrical Tubes ◽  
Allowable Load ◽  
Design Requirements ◽  
Energy Absorbers ◽  
Crushing Behavior

In this paper explicit finite element codes of LS DYNA are applied to simulate the crushing behavior of cylindrical metallic impact energy absorbers with annular machined grooves and the validation of the simulation results are done by comparing with experimental and theoretical findings from the literature. Some efforts are made to find the optimum groove geometry of the tubes by considering two criteria such as the maximum absorbed energy per unit mass (SEA) and maximum ratio of average load to maximum load during crushing (CFE). Maximum allowable load during crushing and the geometrical limits that should not exceed some specified boundaries are considered as design constrains. Based on design of experiment technique (DOE) the conditions that the results should be taken are determined and consequently, response surface (RS) models are created to build a composite objective function that considers both CFE and SEA. Genetic algorithm is applied to find the optimal point for the composite function that meets the design requirements.

Integrally-Stiffened Composite Damage Tolerance Evaluated by Computational Simulation

2001 ◽  
Author(s):  
Christos C. Chamis ◽  
Levon Minnetyan
Keyword(s):  
Material Properties ◽  
Composite Structures ◽  
Failure Modes ◽  
Damage Tolerance ◽  
Epoxy Composite ◽  
Computational Simulation ◽  
Computer Code ◽  
Simulation Design ◽  
Damage Initiation ◽  
Composite Damage

Abstract An integrally stiffened graphite/epoxy composite rotorcraft structure is evaluated via computational simulation. A computer code that scales up constituent micromechanics level material properties to the structure level and accounts for all possible failure modes is used for the simulation of composite degradation under loading. Damage initiation, growth, accumulation, and propagation to fracture are included in the simulation. Design implications with regard to defect and damage tolerance of integrally stiffened composite structures are examined. A procedure is outlined regarding the use of this type of information for setting quality acceptance criteria, design allowables, damage tolerance, and retirement-for-cause criteria.

scholarly journals Energy Absorption Characteristics of Foam Filled Tri Circular Tube under Bending Loads

2021 ◽  
Vol 15 ◽  
pp. 159-164
Author(s):  
Fauzan Djamaluddin
Keyword(s):  
Energy Absorption ◽  
Failure Modes ◽  
Circular Tube ◽  
Comparative Investigation ◽  
Tubular Structures ◽  
Vehicle Engineering ◽  
Bending Resistance ◽  
Bending Loads ◽  
Foam Filled ◽  
Energy Absorbing

In this study, the researcher carried out a comparative investigation of the crashworthy features of different tubular structures with a quasi-static three bending point, like the foam-filled two and tri circular tube structures. Energy absorption capacities and failure modes of different structures are also studied. Furthermore, the general characteristics are investigated and compared for instance the energy absorption, specific energy absorption and energy-absorbing effectiveness for determining the potential structural components that can be used in the field of vehicle engineering. Experimental results indicated that under the bending conditions, the tri foam-filled structures were higher crashworthiness behaviour than the two foam-filled circular structures. Therefore, this study recommended the use of crashworthy structures, such as foam-filled tri circular tubes due to the increased bending resistance and energy-absorbing effectiveness.

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