Quantification of energy absorption capacity of trees against rockfall using finite element analysis

2007 ◽  
pp. 359-364 ◽  
Author(s):  
M Jonsson ◽  
A Volkwein ◽  
W Ammann
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Energy Absorption ◽  
Absorption Capacity ◽  
Energy Absorption Capacity ◽  
Element Analysis

The equivalent method of double V-wing honeycombs on the in-plane dynamic impact

2021 ◽  
pp. 073168442199086
Author(s):  
Yunfei Qu ◽  
Dian Wang ◽  
Hongye Zhang
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Elastic Modulus ◽  
Energy Absorption ◽  
Width Ratio ◽  
Size Factor ◽  
Dynamic Impact ◽  
Element Analysis ◽  
Equivalent Method

The double V-wing honeycomb can be applied in many fields because of its lower mass and higher performance. In this study, the volume, in-plane elastic modulus and unit cell area of the double V-wing honeycomb were analytically derived, which became parts of the theoretical basis of the novel equivalent method. Based on mass, plateau load, in-plane elastic modulus, compression strain and energy absorption of the double V-wing honeycomb, a novel equivalent method mapping relationship between the thickness–width ratio and the basic parameters was established. The various size factor of the equivalent honeycomb model was denoted as n and constructed by the explicit finite element analysis method. The mechanical properties and energy absorption performance for equivalent honeycombs were investigated and compared with hexagonal honeycombs under dynamic impact. Numerical results showed a well coincidence for each honeycomb under dynamic impact before 0.009 s. Honeycombs with the same thickness–width ratio had similar mechanical properties and energy absorption characteristics. The equivalent method was verified by theoretical analysis, finite element analysis and experimental testing. Equivalent honeycombs exceeded the initial honeycomb in performance efficiency. Improvement of performance and weight loss reached 173.9% and 13.3% to the initial honeycomb. The double V-wing honeycomb possessed stronger impact resistance and better load-bearing capacity than the hexagonal honeycomb under impact in this study. The equivalent method could be applied to select the optimum honeycomb based on requirements and improve the efficiency of the double V-wing honeycomb.

Mechanical Design, Additive Manufacturing, and Performance of Equal Volume Metamaterials

2021 ◽  
Author(s):  
Richárd Horváth ◽  
Vendel Barth ◽  
Viktor Gonda ◽  
Mihály Réger ◽  
Imre Felde
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Energy Absorption ◽  
Mechanical Design ◽  
Area Under The Curve ◽  
Cell Number ◽  
Element Analysis ◽  
Cross Sectional ◽  
Unit Cells ◽  
And Performance

Abstract In this paper, we study the energy absorption of metamaterials composed of unit cells whose special geometry makes the cross-sectional area and the volume of the bodies generated from them constant (for the same enclosing box dimensions). After a parametric description of such special geometries, we analyzed by finite element analysis the deformation of the metamaterials we have designed during compression. We 3D printed the designed metamaterials from plastic to subject them to real compression. The results of the finite element analysis were compared with the real compaction results. Then, for each test specimen, we plotted its compaction curve. By fitting a polynomial to the compaction curves and integrating it (area under the curve), the energy absorption of the samples can be obtained. As a result of these investigations, we drew a conclusion about the relationship between energy absorption and cell number.

Experimental and numerical study on the crashworthiness evaluation of an intercity coach under frontal impact conditions

2020 ◽  
Vol 234 (13) ◽  
pp. 3026-3041 ◽  
Author(s):  
Mehmet Ali Güler ◽  
Muhammed Emin Cerit ◽  
Sinem Kocaoglan Mert ◽  
Erdem Acar
Keyword(s):  
Finite Element ◽  
Energy Absorption ◽  
Numerical Study ◽  
Absorption Capacity ◽  
The Body ◽  
Steering Wheel ◽  
Energy Absorption Capacity ◽  
Bus Structure ◽  
Bus Body ◽  
Absorption Characteristics

In this study, the energy absorption capacity of a front body of a bus during a frontal crash was investigated. The strength of the bus structure was examined by considering the ECE-R29 European regulation requirements. The nonlinear explicit finite element code LS-DYNA was used for the crash analyses. First, the baseline bus structures without any improvements were analyzed and the weak parts of the front end structure of the bus body were examined. Experimental tests are conducted to validate the finite element model. In the second stage, the bus structure was redesigned in order to strengthen the frontal body. Finally, the redesigned bus structure was compared with the baseline model to meet the requirements for ECE-R29. In addition to the redesign performed on the body, energy absorption capacity was increased by additional energy absorbers employed in the front of bus structure. This study experimentally and numerically investigated the energy absorption characteristics of a steering wheel armature in contact with a deformable mannequin during a crash. Variations in the location of impact on the armature, armature orientation, and mannequin were investigated to determine the effects of the energy absorption characteristics of the two contacting entities.

Energy-Based Crashworthiness Optimization for Multiple Vehicle Impacts

2004 ◽  
Author(s):  
H. Fang ◽  
K. Solanki ◽  
M. F. Horstemeyer
Keyword(s):  
Finite Element ◽  
Energy Absorption ◽  
Absorption Capacity ◽  
Full Scale ◽  
Side Impact ◽  
Frontal Impact ◽  
Vehicle Model ◽  
Energy Absorption Capacity ◽  
Side Impacts ◽  
Design Variables

In this paper, we use a full-scale finite element vehicle model of a 1996 Dodge Neon in simulating two types of vehicle crashes, offset-frontal and side impacts. Based on an analysis of the vehicle’s histories of internal energy absorption under both impacts, we select twenty components as design variables in the optimization of the vehicle’s weight without decreasing the vehicle’s energy absorption capacity and energy absorption rate. We use the second-order polynomials in creating the metamodels for the response functions of energy absorption under both impacts. The optimization result shows a significant reduction on the total weight of the selected components. The LS-DYNA MPP v970 and a full-scale finite element vehicle model of 320,872 nodes and 577,524 elements are used in the simulations. A simulation of 100 ms offset-frontal impact takes approximately 17 hours with 36 processors on the IBM Linux SuperCluster, which has a total of 1038 Intel Pentium III 1.266 GHz processors and 607.5 GB RAM. A simulation of 100 ms side impact takes approximately 29 hours with the same condition as the offset-frontal simulation.

Energy Absorption Characteristics of a Carbon Fiber Composite Automobile Lower Rail: A Comparative Study

2015 ◽  
Author(s):  
Muhammad Ali ◽  
Khairul Alam ◽  
Eboreime Ohioma
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Energy Absorption ◽  
Reactive Force ◽  
Element Analysis ◽  
Cross Sectional Dimension ◽  
Force Displacement ◽  
Absorption Characteristics

Composite materials have emerged as promising materials in applications where low weight and high strengths are desired. Aerospace industry has been using composite materials for past several decades exploiting their characteristics of high strength to weight ratio over conventional homogenous materials. To provide a wider selection of materials for design optimization, and to develop lighter and stronger vehicles, automobile industries have been exploring the use of composites for a variety of components, assemblies, and structures. Composite materials offer an attractive alternate to traditional metals as designers have greater flexibility to optimize material and structural shapes according to functional requirements. However, any automotive structure or part constructed from composite materials must meet or exceed crashworthiness standards such as Federal Motor Vehicle Safety Standard (FMVSS) 208. Therefore, for a composite structure designed to support the integrity of the automotive structure and provide impact protection, it is imperative to understand the energy absorption characteristics of the candidate composite structures. In the present study, a detailed finite element analysis is presented to evaluate the energy absorbing characteristics of a carbon fiber reinforced polymer composite lower rail, a critical impact mitigation component in automotive chassis. For purposes of comparison, the analysis is repeated with equivalent aluminum and steel lower rails. The study was conducted using ABAQUS CZone module, finite element analysis software. The rail had a cross-sectional dimension of 62 mm (for each side), length of 457.2 mm, and a wall thickness of 3.016 mm. These values were extracted from automobile chassis manufacturer’s catalog. The rail was impacted by a rigid plate of mass 1 tonne (to mimic a vehicle of 1000 Kg gross weight) with an impact velocity of 35 mph (15646.4 mm/s), which is 5 mph over the FMVSS 208 standard, along its axis. The simulation results show that the composite rail crushes in a continuous manner under impact load (in contrast to a folding collapse deformation mode in aluminum and steel rails) which generates force-displacement curve with invariable crushing reactive force for the most part of the crushing stroke. The energy curves obtained from reactive force-displacement graphs show that the composite rail absorbs 240% and 231% more energy per unit mass as compared to aluminum and steel rails. This shows a significant performance enhancement over equivalent traditional metal (aluminum and steel) structures and suggests that composite materials in conjunction with cellular materials/configurations have a tremendous potential to improve crashworthiness of automobiles while offering opportunities of substantial weight reductions.

scholarly journals Post Tensioned CFRP tubes for improved energy absorption

2021 ◽  
Author(s):  
Venkateswarlu Gattineni ◽  
◽  
Venukumar Nathi ◽  
Keyword(s):  
Energy Absorption ◽  
Impact Energy ◽  
Absorption Capacity ◽  
Energy Absorption Capacity ◽  
Element Analysis ◽  
Simulation Techniques ◽  
Thin Tube ◽  
Post Tensioning ◽  
Cfrp Tubes ◽  
Post Tensioned

Thin-walled tubes made of CFRP (Carbon fiber reinforced Polymer) are being increasingly used as CC (Crush Cans) due to their higher specific energy absorption capacity in the automotive domain for absorbing impact energy during a frontal crash. Finite element analysis (FEA) based computational methods have matured over the years with increased accuracy and acceptable correlation with experimental results. FEA-based computational studies when used appropriately can reduce the number of physical tests and prototypes required besides accelerating the overall cycle design time. The present work proposes an FEA based design validation approach for the evaluation of post-tensioned crush can design that can absorb more impact energy compared to a normal CFRP thin tube. The FEM based method uses a combination of multiple simulation techniques to predict the behavior of a post-tensioned tube. The post-tensioning in the present work has been proposed in the form of internal pressure for the thin tube. It was found that a safe value of pressure, when applied as a post-tensioning load, can improve the energy absorption capacity without increasing the weight of the tube.

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