1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationRoad restraint systems Guidelines for computationalmechanics of crash testingagainst vehicle restraint systemPart 3: Test Item Modelling and VerificationPD CEN/TR 16303-3:2012Nat
2、ional forewordThis Published Document is the UK implementation of CEN/TR 16303-3:2012.The UK participation in its preparation was entrusted by Technical CommitteeB/509, Road equipment, to Subcommittee B/509/1, Road restraint systems.A list of organizations represented on this committee can be obtain
3、ed onrequest to its secretary.This publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application. The British Standards Institution 2012Published by BSI Standards Limited 2012ISBN 978 0 580 75312 1ICS 13.200; 93.080.30Compliance
4、with a British Standard cannot confer immunity fromlegal obligations.This Published Document was published under the authority of theStandards Policy and Strategy Committee on 31 March 2012.Amendments issued since publicationAmd. No. Date Text affectedPUBLISHED DOCUMENTPD CEN/TR 16303-3:2012TECHNICA
5、L REPORT RAPPORT TECHNIQUE TECHNISCHER BERICHT CEN/TR 16303-3 January 2012 ICS 13.200; 93.080.30 English Version Road restraint systems - Guidelines for computational mechanics of crash testing against vehicle restraint system - Part 3: Test Item Modelling and Verification Dispositifs de retenue rou
6、tiers - Recommandations pour la simulation numrique dessai de choc sur des dispositifs de retenue des vhicules - Partie 3: Composition et vrification des modles numriques de dispositifs dessaiRckhaltesysteme an Straen - Richtlinien fr Computersimulationen von Anprallprfungen an Fahrzeug-Rckhaltesyst
7、eme - Teil 3: Modellierung des Prfgegenstands und berprfung This Technical Report was approved by CEN on 7 November 2011. It has been drawn up by the Technical Committee CEN/TC 226. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark,
8、 Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMA
9、LISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2012 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. CEN/TR 16303-3:2012: EPD CEN/TR 16303-3:2012CEN/TR 16303-3:2012 (E) 2 Contents Foreword
10、3Introduction . 41 Scope 52 Normative references 53 General considerations on the modelling technique . 54 VRS model 65 Verification of the model . 86 Collection Data . 10Annex A Recommendations for the mesh of Finite Element VRS models addressed to crash simulations . 11Annex B Recommendations for
11、development of Multi-Body VRS models addressed to crash simulations . 14Annex C Phenomena importance ranking table for test Items 15Bibliography 19PD CEN/TR 16303-3:2012CEN/TR 16303-3:2012 (E) 3 Foreword This document (CEN/TR 16303-3:2012) has been prepared by Technical Committee CEN/TC 226 “Road eq
12、uipment”, the secretariat of which is held by AFNOR. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document consists of this do
13、cument divided in five Parts under the general title: Guidelines for Computational Mechanics of Crash Testing against Vehicle Restraint System: Part 1: Common reference information and reporting Part 2: Vehicle Modelling and Verification Part 3: Test Item Modelling and Verification Part 4:Validation
14、 Procedures Part 5: Analyst Qualification11In preparation PD CEN/TR 16303-3:2012CEN/TR 16303-3:2012 (E) 4 Introduction This part of this Technical Report is meant to provide the user with all the information necessary for the development of a complete and efficient numerical model of a test item veh
15、icle in order to properly simulate a crash event. The vehicle restraint system (VRS) models represent the test item in a certification test according EN 1317. The model shall faithfully depict the performance of a VRS so that the performance criteria identified in EN 1317 can be extracted from the s
16、imulation of a vehicle impact with the VRS model. The VRS simulation can only be assessed in combination with a validated vehicle model described in CEN/TR 16303-2. There are different types of VRS and they can incorporate concrete, metal, plastic, and composite materials in their construction. Each
17、 system has different modelling requirements and the following manual describes the guidelines applicable for all VRS. It is important to recognize that the requirements for modelling a deformable VRS are significantly different from a rigid systems and the latter are not covered in this version of
18、the guidelines. This document currently focuses on Finite Element simulation methodologies. Rigid body (or multi-body) dynamic codes are also used in the development of a VRS. The VRS model requirements are not the same as for the Finite Element approach and shall be consistent to the methodology. T
19、he CM/E group does not yet have guidelines for the use of rigid body codes and their application for certification requirement cannot be recommended until they are similarly defined. PD CEN/TR 16303-3:2012CEN/TR 16303-3:2012 (E) 5 1 Scope The aim of this Technical Report is to provide a step-by-step
20、 description of the development process of a reliable VRS model for the simulations of full-scale crash tests. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated reference
21、s, the latest edition of the referenced document (including any amendments) applies. EN 1317-1, Road restraint systems Part 1: Terminology and general criteria for test methods EN 1317-2, Road restraint systems Part 2: Performance classes, impact test acceptance criteria and test methods for safety
22、barriers including vehicle parapets EN 1317-3, Road restraint systems Part 3: Performance classes, impact test acceptance criteria and test methods for crash cushions ENV 1317-4, Road restraint systems Part 4: Performance classes, impact test acceptance criteria and test methods for terminals and tr
23、ansitions of safety barriers EN 1317-5, Road restraint systems Part 5: Product requirements and evaluation of conformity for vehicle restraint systems prCEN/TR 1317-6, Road restraint systems Part 6: Pedestrian restraint system, pedestrian Parapets (under preparation) prEN 1317-8, Road restraint syst
24、ems Part 8: Motorcycle road restraint systems which reduce the impact severity of motorcyclist collisions with safety barriers CEN/TR 16303-2:2011, Road restraint systems Guidelines for computational mechanics of crash testing against vehicle restraint system Part 2: Vehicle Modelling and Verificati
25、on CEN/TR 16303-4:2011, Road restraint systems Guidelines for computational mechanics of crash testing against vehicle restraint system Part 4: Validation Procedures 3 General considerations on the modelling technique 3.1 General Particular attention shall be paid on the geometrical description of t
26、he contact areas of the VRS model. Proper geometry and material properties shall be used. The fixation of the VRS to the roadbed shall correspond to the test conditions reflected by the standard and the application of the VRS. Modelling of any soil, asphalt, concrete, etc. element should be document
27、ed. Simplifications as well as rigid soil conditions shall be justified through empirical or engineering analyses independent of the computer model. The model shall include all significant parts, the connections between the parts, and appropriate boundary conditions. PD CEN/TR 16303-3:2012CEN/TR 163
28、03-3:2012 (E) 6 3.2 Finite Element and Multi-body approaches 3.2.1 General Two main modelling approaches can be considered, using two different analysis tools: the Finite Element Method (FEM) and the Multi-Body (MB) approach. Both methods are widely known and broadly used in many fields of engineeri
29、ng, including the Automotive Industry. The first method allows the user to build a very detailed vehicle model and to assess global results such as the barrier or vehicle performance in a crash test as well as the stress data in a local area of the vehicle. As a counterpart, a FEM analysis requires
30、significant computational costs, thus proving less valid for parametric studies where a large number of simulations may be required. Once the VRS model has been built, it shall be validated with simple tests, such as component tests and then full-scale dynamic tests. Validation procedures are listed
31、 in a separate document (CEN/TR 16303-4). These validation tests ensure the global response of the model is appropriate and any simplifications of the model still reproduce the functionality of the system. Numerical stability of the model can be assessed during the validation process. Subsequently,
32、the model can be used to simulate full-scale crash tests within the application areas accepted in EN 1317. Furthermore Computation mechanics when validated can provide support in real life situations that are not described within EN 1317. 3.2.2 Finite Element guidelines Crash tests finite element (F
33、E) simulations are usually run with a dynamic, non-linear and explicit finite element code. Computer runtime is usually significant, with the order of 30-40 hours on a 2,4 GHz personal computer for the simulation of a full-scale crash test with an effective simulated time of 0,25 second. In fact, th
34、e model shall include not only the vehicle model, but also several meters of roadside barriers (depending on the barrier type, up to 80 meters of barrier) to faithfully reproduce the interaction between the vehicle and the barrier and the boundary conditions. The integration time step is controlled
35、by the minimum dimension of the smallest element of the FE mesh, therefore, the mesh size shall be a trade-off between the need for geometrical and numerical accuracy and computational cost: large elements guarantee a high time step but poor accuracy of the model and possible instabilities, while sm
36、all elements give a better accuracy but a smaller time step. General criteria for Finite Element modelling techniques are identified in Annex A. The most significant parts of the VRS shall be modelled explicitly with a detailed mesh. Simplifications of certain structures (bolts, slots, etc.) are acc
37、eptable if the appropriate functionality is incorporated. For example, bolted connections can be replaced by beam elements if the appropriate failure characteristics of the beam elements are incorporated. 3.2.3 Multi-body guidelines The MB approach consists in modelling the VRS with a number of rigi
38、d bodies connected by means of joints with specified stiffness characteristics. When reliable and validated data are available, the MB approach is very useful to perform parametric studies or big test scenario, since the computational cost of the analysis can be dramatically less than that of the co
39、rresponding FEM analysis. 4 VRS model 4.1 Component to be modelled The majority of elements in a road restraint system lend themselves to direct geometric digitisation in a FE or MB model. These elements are (but not limited to): 1) posts; 2) horizontal elements; a. metal beams; PD CEN/TR 16303-3:20
40、12CEN/TR 16303-3:2012 (E) 7 b. cables; 3) block-out beams / spacers; 4) bolted connections; 5) concrete elements; 6) soil. General mesh specifications for FE method are listed in Annex A. These specifications are based on the date of publication (March 2006) level of simulation activities in researc
41、h and product development. As general practice, the mesh size and arrangements shall permit the observed (or expected) deformed shape of the parts. Once a mesh specification has been determined, it becomes a practical issue to determine to which extent this mesh shall be applied to the entire test o
42、bject. The level of detail required in the deformed parts may not need to be applied to all structures that are not subject to local buckling phenomena or other high stress gradients. Recommendations for the development of Multi-Body VRS models, addressed to crash simulations method, are listed in A
43、nnex B. 4.2 Coordinate system The model of the test article should be defined with a consistent coordinate system. The origin of the coordinate system may differ for the analysts or system modelling requirements, but the orientation of the axis should follow the following principles: X axis oriented
44、 along the traffic face of the system for redirective features. Symmetrical structures (crash cushions) may use the axis of symmetry. The positive direction is in the direction of traffic flow. Y axis oriented normal to the X axis, parallel to the plane of the road with the positive direction orient
45、ed towards the traffic face of the structure. Z axis oriented normal to the X-Y plane with the positive direction such that the X-Y-Z triad follows the right hand rule. An example of the coordinate system for a safety barrier is shown in Figure 1. Note that that the origin of the coordinate system i
46、s moved away from the VRS for clarity. a) Plan View b) View a-a Figure 1 Vehicle Restraint System Coordinate Systems The preferred units for the models are millimetres, newton, tons and seconds. These units guarantee consistency of results and are consistent with the vehicle modelling guidelines in
47、CEN/TR 16303-2. Nodal coordinates should be defined in the test articles reference frame. PD CEN/TR 16303-3:2012CEN/TR 16303-3:2012 (E) 8 In case of FE models the fibre direction for all the shell elements should be coherent (same orientation, except in case of contact definition regions). 4.3 Mater
48、ial models 4.3.1 General The types of materials used in the test article will define the type of material model definitions used in the simulation models. The material properties should reflect the properties of the actual part after manufacture. Thus representative specimen tests should be used as
49、much as possible to represent the current state of the material properties. 4.3.2 Material modelling for dynamic finite elements simulations The most common materials for test articles are steel and these materials lend themselves to commonly used material models. For example in LS-DYNA: *MAT_ELASTIC, *MAT_PIECEWISE_LINEAR_PLASTICITY, *MAT_PLASTIC_KINEMATIC Each material model has its own input requirements that should be obtained from laboratory tests of coupons or simila
