The Energy-Absorbing Characteristics of Tubular Structures With Geometric and Material Modifications: An Overview

2008 ◽  
Vol 61 (2) ◽  
Author(s):  
S. Chung Kim Yuen ◽  
G. N. Nurick
Keyword(s):  
Kinetic Energy ◽  
Structural Integrity ◽  
Impact Loads ◽  
Tubular Structures ◽  
Axial Impact ◽  
Specific Location ◽  
Crushing Force ◽  
Axial Response ◽  
Tubular Sections ◽  
Energy Absorbing

For better crashworthiness performance, vehicles must protect its occupants by maintaining structural integrity and converting the large amount of kinetic energy into other forms of energy in a controllable and predictable manner in a crash situation. In doing so, lower crushing force would provide better safety for the vehicle occupants. This paper reviews the axial response of “modified” tubular sections with imperfections and fillers subjected to axial impact loads relevant to the field of structural crashworthiness. The use of imperfections sets the mode and initiation of collapse of a tube at a specific location and reduces the maximum crush force, hence improving the energy-absorbing characteristics of tubular structures. The types of imperfections discussed include prebuckle, parallel and dished indentations, cutouts, stiffeners, fillers, and wrapping.

scholarly journals Crashworthiness Characteristics of Multi-Cell Tubular Structures Subjected to Axial Impact

2019 ◽  
Vol 8 (4) ◽  
pp. 3911-3915 ◽  
Keyword(s):  
Impact Energy ◽  
Deformation Behaviour ◽  
Initial Period ◽  
Geometrical Parameters ◽  
Tubular Structures ◽  
Axial Impact ◽  
Thin Walled ◽  
Energy Absorbing ◽  
Impact Simulations ◽  
The Impact

To mitigate the impact forces in crash events, thin-walled tubular elements are employed as an energy absorbing attenuators in frontal part of the automotive vehicles. To develop more progressive deformation modes, at the initial period, and to absorb more impact energy at the final period of crash, it is significant to enhance the crashworthiness performance of the tube by modifying its geometrical parameters. Multi-cell tubular structures have recognized to own superior impact energy absorbing ability and lightweight effect in the modern automotive vehicles. This research article examines the deformation behaviour of thin walled aluminum alloy multi-cell tube with different stiffeners exposed to axial impact loading using numerical simulation. Nonlinear impact simulations were performed on multi-cell tubes using finite element ABAQUS/CAE explicit code. From the overall results obtained, the deformation behaviour of multi-cell tubes was compared. Furthermore, hexagonal tubes with stiffeners were retained as most prominent for better energy dissipation. This type of tube was found to be most efficient type to enhance the crashworthiness performance during axial impact.

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.

Failure Projection of Corroding Bridge Post-Tensioned Tendons Considering Partitioned Attack

CORROSION ◽  
10.5006/3728 ◽  
2021 ◽  
Author(s):  
William Hartt
Keyword(s):  
Corrosion Rate ◽  
Material Properties ◽  
Analytical Modeling ◽  
Structural Integrity ◽  
Free Water ◽  
Reinforced Concrete Structures ◽  
Bridge Structure ◽  
Specific Location ◽  
Corrosion Rates ◽  
Wire Strand

Post-tensioning (PT) has evolved to become an important technology for affecting integrity of large, increasingly sophisticated reinforced concrete structures. In the case of bridges, however, tendon failures resulting from wire/strand corrosion have been reported as early as two years post construction. In response to this, a recent study introduced, evaluated, and employed an analytical modeling approach that projects timing of such failures, given statistics which characterize the distribution of wire corrosion rate. These efforts all considered that corrosion penetration is normally distributed across the entire population of wires comprising all tendons. However, it has been reported that corrosion, resultant wire and strand fractures, and tendon failures can be confined to a specific location on a bridge structure as a result of variations in material properties or construction improprieties (or both). Also, the distribution of corrosion rates can differ within individual tendons because of, first, variations in grout structure and composition and, second, presence of voids and free water. The present research extends these previous efforts and addresses such situations; that is, those where the corrosion rate distribution is spatially variable. The results are discussed within the context of better assuring structural integrity for PT bridges.

Design of a Hybrid Lightweight Energy Absorber

2016 ◽  
Vol 713 ◽  
pp. 321-324
Author(s):  
A. de Luca ◽  
Giuseppe Lamanna ◽  
Raffaele Sepe ◽  
Alessandro Soprano
Keyword(s):  
Kinetic Energy ◽  
Numerical Investigation ◽  
Structural Design ◽  
Carbon Composite ◽  
Energy Absorber ◽  
Load Paths ◽  
Passenger Safety ◽  
Carbon Composite Materials ◽  
Energy Absorbers ◽  
Energy Absorbing

Among several problems which might affect the passenger safety during an accidental crash event, the deceleration pulse is one of the most critical. For this reason vehicles are designed to convert the Kinetic Energy occurring in an impact in plastic deformation and to spread the loads due to such events through designed structural load paths. An important role in the kinetic energy absorbing at high velocities is played by the energy absorbers. The energy absorption capability of a crashworthy element or system is largely affected by material properties and structural design. This work deals with a numerical investigation on the energy absorbing capability of a new concept of energy absorber made out of the combination of metal parts and carbon composite materials. A numerical investigation on the parameters which increase the crash performance as well as decrease the weight of such device has been presented in this paper.

Design by Analysis of Waste Packages at Yucca Mountain for Impact Loads

2009 ◽  
Author(s):  
Randy J. James ◽  
Kenneth Jaquay ◽  
Michael J. Anderson
Keyword(s):  
Nuclear Waste ◽  
Impact Loading ◽  
Structural Integrity ◽  
Structural Response ◽  
Yucca Mountain ◽  
Impact Loads ◽  
Geologic Repository ◽  
Dynamic Simulations ◽  
Nuclear Waste Storage ◽  
Waste Package

The proposed geologic repository under development at Yucca Mountain, Nevada, will employ multiple shell metallic containers (waste packages) for the disposal of nuclear waste. The waste packages represent a primary engineered barrier for protection and containment of the radioactive waste, and the design of these containers must consider a variety of structural conditions to insure structural integrity. Some of the more challenging conditions for structural integrity involve severe impact loading due to hypothesized event sequences, such as drops or collisions during transport and placement. Due to interactions between the various components leading to complex structural response during an impact sequence, nonlinear explicit dynamic simulations and highly refined models are employed to qualify the design for these severe impact loads. This paper summarizes the Design by Analysis methodologies employed for qualification of waste package design under impact loading and provides several illustrative examples using these methods. Example evaluations include a collision of a waste package by the Transport and Emplacement Vehicle (TEV) and two scenarios due to seismic events, including WP impact within the TEV and impact by falling rock. The examples are intended to illustrate the stringent Design by Analysis methods employed and also highlight the scope of structural conditions included in the design basis for waste packages to be used for proposed nuclear waste storage at Yucca Mountain.

Significance of material constitutive model and forming parameters on the crashworthiness performance of capped cylindrical tubular structures

2019 ◽  
Vol 234 (2) ◽  
pp. 320-334
Author(s):  
Praveen Kumar A ◽  
Afdhal Akbar ◽  
Annisa Jusuf ◽  
Leonardo Gunawan
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Performance Indicators ◽  
Thickness Distribution ◽  
Material Constitutive Model ◽  
Numerical Predictions ◽  
Forming Parameters ◽  
Crushing Force ◽  
Cylindrical Tubes ◽  
Energy Absorbing

An accuracy of crushing performance indicators is critical to evaluate in finite element crushing simulations particularly for the press-formed capped tubular energy absorbing structures. It is essential to select the appropriate material constitutive model and to incorporate the forming parameters into the finite element crushing model as a vital input. Hence in the present article, the influence of various material constitutive models and forming (multi-stage deep drawing) parameters on the axial crashworthiness characteristics of thin-walled capped cylindrical tubes were investigated numerically. Both forming and crushing simulations were executed by nonlinear finite element LS-DYNA® code. The forming parameters such as thickness distribution, residual stress, and effective plastic strain were mapped to a finite element crushing model of the tube. The numerical predictions of the thickness distribution and final deformed profiles of the capped cylindrical tubes are correlated with the experiments. The results revealed that the forming parameters have a substantial effect on the crushing performance of the deep drawn capped cylindrical tubes. As a result of these analyses, the thickness and strain predictions strengthens the tube and significantly influenced the crushing performance indicators such as initial peak crushing force, mean crushing force, and the energy absorbing capacity.

Axial crushing force of externally fibre-reinforced metal tubes

2002 ◽  
Vol 216 (9) ◽  
pp. 863-874 ◽  
Author(s):  
X Wang ◽  
G Lu
Keyword(s):  
Theoretical Model ◽  
Impact Load ◽  
Bare Metal ◽  
Axial Impact ◽  
Axial Crushing ◽  
Crushing Force ◽  
Collapse Mode ◽  
The Mean

Based on the classical Alexander solution for the axial collapse of bare metal tubes, a theoretical model is presented to predict the mean crushing force of arbitrarily fibre-reinforced metal tubes with a ring collapse mode. The derived mean crushing force and length of the local folding wave are more reasonable and are in better agreement with the experiments than previously obtained. The effect of wrapping direction of the reinforcing fibres is studied. This model for predicting the static mean crushing force can be extended for the dynamic mean crushing force of fibre-reinforced metal tubes under axial impact load.

Experimental analysis on the axial crushing and energy absorption characteristics of novel hybrid aluminium/composite-capped cylindrical tubular structures

2019 ◽  
Vol 233 (11) ◽  
pp. 2234-2252 ◽  
Author(s):  
A Praveen Kumar
Keyword(s):  
Energy Absorption ◽  
Specific Energy ◽  
Cylindrical Tube ◽  
Tubular Structures ◽  
Aluminium Composite ◽  
Specific Energy Absorption ◽  
Cylindrical Tubes ◽  
Impact Crushing ◽  
Energy Absorbing ◽  
The Impact

In recent years, aluminium-composite hybrid tubular structures, which combine the stable and progressive plastic deformation of the aluminium metal with light-weight composite materials, are obtaining increased consideration for meeting the advanced needs of crashworthiness characteristics. This research article presents the experimental outcomes of novel aluminium/composite-capped cylindrical tubes subjected to quasi-static and impact axial loads. The influence of various capped geometries in the aluminium segment and three different fabrics of the composite segment in the cylindrical tube are investigated experimentally. The outcomes of the impact crushing test are also correlated with the quasi-static results of the proposed aluminium/composite-capped cylindrical tubes. The overall outcomes revealed that the crashworthiness characteristics of crushing force consistency and specific energy absorption of the aluminium-composite hybrid tubes are superior to those of the bare aluminium tubes. When the glass fabric/epoxy composite is wrapped to aluminium cylindrical tubes, the specific energy absorption increases about 23–30%, and the wrapping of hybrid glass/kenaf fabrics increases the specific energy absorption of almost 40–52%. Such a hybrid tubular structures would be of huge prospective to be used as effective energy-absorbing devices in aerospace and automotive applications. A further benefit of the composite-wrapping approach is that the composite might be retro-fitted to aluminium tubes, and the energy absorption capability is shown to be significantly enhanced by such utilization.

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