scholarly journals Application of smart honeycomb structures for automotive passive safety

2017 ◽  
Vol 232 (6) ◽  
pp. 797-811 ◽  
Author(s):  
Olga A Ganilova ◽  
Jia J Low
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Permanent Deformation ◽  
Element Model ◽  
Negative Stiffness ◽  
Passive Safety ◽  
Bumper Beam ◽  
Energy Absorbers ◽  
Energy Absorbing ◽  
Comprehensive Study

Nowadays, most energy-absorbing devices used in industry absorb energy through permanent deformation. In some cases, consumers have to repair or even replace energy absorbers even after a mild collision. The work presented in this paper proposes a novel reusable solution in the form of a hybrid bumper–crush can design where a recoverable structure is integrated into the bumper beam and crush can for a mild-collision situation in addition to the traditional energy absorbers recommended for more severe collisions. The main investigation is focused around the performance and optimisation of a negative-stiffness honeycomb, the recoverable structure and the honeycomb-filled elements. A comprehensive study was carried out to investigate numerically the behaviour of these energy-absorbing structures in crash conditions, corresponding to real scenarios and simulated using a specially developed finite element model.

Finite-Element Modelling of Ballistic Impact of Plain-Woven Aramid Fabric

2014 ◽  
Vol 553 ◽  
pp. 769-773 ◽  
Author(s):  
E.A. Flores-Johnson ◽  
J.G. Carrillo ◽  
R.A. Gamboa ◽  
Lu Ming Shen
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Finite Element Modelling ◽  
Permanent Deformation ◽  
Element Model ◽  
Ballistic Impact ◽  
Elastic Model ◽  
Numerical Predictions ◽  
Aramid Fabric ◽  
The Finite Element Model

In this work, a 3D finite-element model of the ballistic impact of a multi-layered plain-woven aramid fabric style 720 (Kevlar®129 fibre, 1420 denier, 20×20 yarns per inch) impacted by a 6.7-mm spherical projectile was built at the mesoscale in Abaqus/Explicit by modelling individual crimped yarns. Material properties and yarn geometry for the model were obtained from reported experimental observations. An orthotropic elastic model with a failure criterion based on the tensile strength of the yarns was used. Numerical predictions were compared with available experimental data. It was found that the finite-element model can reproduce the physical experimental observations, such as the straining of primary yarns and pyramidal-shaped deformation after perforation. The permanent deformation of fabric targets predicted by the numerical simulations was compared with available experimental results. It was found that the model fairly predicted the permanent deformation with a difference of about 21% when compared with experiments.

scholarly journals Helmet Design Based on the Optimization of Biocomposite Energy-Absorbing Liners under Multi-Impact Loading

2019 ◽  
Vol 9 (4) ◽  
pp. 735 ◽  
Author(s):  
Fábio Fernandes ◽  
Ricardo Alves de Sousa ◽  
Mariusz Ptak ◽  
Gonçalo Migueis
Keyword(s):  
Finite Element ◽  
Injury Risk ◽  
Permanent Deformation ◽  
Viscoelastic Behavior ◽  
Element Model ◽  
Expanded Polystyrene ◽  
Head Model ◽  
Protective Gear ◽  
Motorcycle Helmet ◽  
Energy Absorbing

Cellular materials have been used in many applications such as insulation, packaging, and protective gear. Expanded polystyrene has been widely used as energy-absorbing liner in helmets due to its excellent cost-benefit relation. This synthetic material can absorb reasonable amounts of energy via permanent deformation. However, in real-world accidents, helmets may be subjected to multi-impact scenarios. Additionally, oil-derived plastic is presently a major source of societal concern regarding pollution and waste. As a sustainable alternative, cork is a natural cellular material with great crashworthiness properties and it has the remarkable capacity to recover after compression, due to its viscoelastic behavior, which is a desired characteristic in multi-impact applications. Therefore, the main goal is to analyze the applicability of agglomerated cork as padding material in safety helmets. First, a finite element model of a motorcycle helmet available on the market was developed to assess its safety performance and to establish a direct comparison between expanded polystyrene and cork agglomerates as liners. Secondly, a new helmet model with a generic geometry was developed to assess the applicability of agglomerated cork as liner for different types of helmets, based on the head injury risk predictions by the finite element head model, YEt Another Head Model (YEAHM), developed by the authors. Several versions of helmet liners were created by varying its thickness and removing sections of material. In other words, this generic helmet was optimized by carrying out a parametric study, and by comparing its performance under double impacts. The results from these tests indicate that agglomerated cork liners are an excellent alternative to the synthetic ones. Thus, agglomerated cork can be employed in protective gear, improving its overall performance and capacity to withstand multi-impacts.

Validation of a Computer Model for Flexible Pipe Crushing Resistance Calculations

2008 ◽  
Author(s):  
Aline Malcorps ◽  
Antoine Felix-Henry
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Plastic Material ◽  
Load Capacity ◽  
Permanent Deformation ◽  
Element Model ◽  
Design Criterion ◽  
Internal Diameter ◽  
Flexible Pipe ◽  
Offshore Field

Several types of laying equipments are used to install flexible pipelines for offshore field developments. These pipelines installation tools apply generally compressive radial forces to hold the pipe suspended weight. The deeper the pipeline has to be laid, the higher is its suspended weight and therefore the higher these radial loads need to be. As each flexible pipe construction is optimized for each field application, a design methodology is necessary to be able to evaluate the radial load acceptable by the flexible pipe. The failure mode associated with this type of loads is an instability thought to be similar to the hydrostatic collapse mode. Therefore an adequate design safety factor has to be considered. The water depth of offshore field developments becoming ever deeper, the resistance of the flexible pipe to installation loads becomes often a driving design criterion. A finite element model to address this type of loading has been developed and improved over the past years. To avoid over-sizing the flexible pipe with current design approach, this finite element model needed to be improved for the latest materials used and for higher crushing loads. To this effect, a new powerful test bench with a crushing load capacity of 1200 tons over one meter has been designed, procured and is now operational. It can handle pipes from 4" to 19" internal diameter. Many types of flexible pipe samples have been tested up to permanent deformation using bi-, tri- and quadri-caterpillar tensioners. The results of these tests have been used to validate a new finite element model using in particular non-linear elasto-plastic material laws. In this paper, several test results will be presented and compared with the calculations. The relevance of different possible design criteria depending on the type of loading regime, the slenderness of the pipe and the number of radially resistant layers, will also be discussed. This new model is operational and allows to optimize the flexible pipe design in particular for ultra-deep water applications down to 2500m or more.

Simulation of Vehicles Frontal Crash with Dummy Inside

2013 ◽  
Vol 760-762 ◽  
pp. 1244-1249
Author(s):  
Yuan Peng Liu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Energy Absorption ◽  
Element Model ◽  
Structure Deformation ◽  
Frontal Crash ◽  
Occupant Injury ◽  
Energy Absorbing

The complete Finite Element Model of vehicle with dummy inside is established. Through analyzing structure deformation and acceleration of the vehicle, the rule of energy absorption and dissipation is obtained, the dummys respond and the collision capability criteria of the head, chest and thigh are achieved. A comprehensive and credible appraisement about the frontal crash process and crashworthiness is proposed by analyzing the effect of the main energy-absorbing components, the transmitted route of the energy and the safety of the vehicle and occupant injury criterions.

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