1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there
2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2011 SAE International All rights reserved. No part of this publication m
3、ay be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-4970 (outside U
4、SA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedbackon this Technical Report, please visit http:/www.sae.org/technical/standards/J2052_201101SURFACEVEHICLEINFORMATIONREPORTJ2052 JAN2011 Issued 1990-03 Revised 2011-01Supersed
5、ing J2052 DEC2005 Test Device Head Contact Duration Analysis A technically equivalent version of SAE J2052 is included in ISO Technical Report 12351. RATIONALE The committee reviewed this information report and determined that no substantial changes were needed. The reference section was reformatted
6、 and updated. FOREWORD A technique has been established for determining head impact contact duration called the “Force Difference Method.“ This technique allows calculation of Head Injury Criterion (HIC) only during head contact. 1. SCOPE This methodology can be used for all calculations of HIC, wit
7、h all test devices having an upper neck triaxial load cell mounted rigidly to the head, and head triaxial accelerometers. 1.1 Purpose The purpose of this SAE Information Report is to describe a computer-adaptable technique for determining head engagement and disengagement times for use in the calcul
8、ation of the HIC without reliance on contact switches or photography. 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this specification to the extent specified herein. Unless otherwise indicated, the latest issue of SAE publications shall apply. Copyright SAE Intern
9、ational Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2052 Revised JAN2011 Page 2 of 62.1.1 SAE Publication Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside U
10、SA and Canada) or 724-776-4970 (outside USA), www.sae.org.SAE J211-1 JUL 2007 Instrumentation for Impact Test 2.1.2 Federal Publication Available from the Superintendent of Documents, U.S. Government Printing Office, Mail Stop: SSOP, Washington, DC 20402-9320. 49 CFR Part 572, Subpart E Occupant Cra
11、sh Protection, revised as of April, 1997 2.1.3 ISO Publication Available from American National Standards Institute, 25 West 43rd Street, New York, NY 10036-8002, Tel: 212-642-4900, www.ansi.org.ISO Technical Report 12351 Determination of head contact and duration in impact testsISO/TC22/SC12/WG3N35
12、5 3. DEFINITIONS 3.1 HIC The HIC is one of the “injury criteria“ prescribed by S6 of the Federal Motor Vehicle Safety Standard (FMVSS) 208. It is the maximum value calculable from the head c.g. resultant acceleration-time profile in accordance with Equation 1: (Eq. 1) where: a is the resultant accel
13、eration expressed as multiples of G (the acceleration of gravity), and t1and t2are any two points in time during the crash. NOTE: Although a HIC window of 36 ms maximum was subsequently mandated by NHTSA, it is not utilized with this document. 3.2 Contact HIC HIC values calculated only during the pe
14、riods of each head contact. 3.3 te, tdThe head engagement and disengagement times, teand tdrespectively, are determined by the method given in Section 5. These are the starting and ending times, i.e., the windows for the iterative HIC calculations for each head contact. NOTE: The maximum contact HIC
15、 for each te, tdinterval will have associated with it times t1, t2which may be equal to, or less than the te, tdinterval. HIC1t2t1() a.dtt1t22.5t2t1()=Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
16、SAE J2052 Revised JAN2011 Page 3 of 63.4 Accelerometers (ax, ay, az)The triaxial accelerometer(s) in the head of the test device will be referred to as an accelerometer, omitting the triaxial classification as defined in SAE J211-1; +axis forward, +ayis to the right, and +azis downward. These orient
17、ations are shown in Figure 1. 3.5 Load Cell The triaxial force load cell (attached rigidly to the base of the skull portion of the test device to which the neck is attached)will be referred to as a load cell, omitting the triaxial and upper neck classification. Load cells with additional outputs can
18、also be used. 3.6 Head Mass (M) The mass of the head including the masses of the head accelerometers and mounting brackets and the mass of the load cell above the gage plane. NOTE: Caution should be exercised to minimize the effect of elements external to the neck, such as neck skins or wires, which
19、 might carry load or modify the head mass. 3.7 Inertial Head Forces (Max, May, Maz)The inertial head forces are calculated from the triaxial accelerometers which are inside the head of the test device. The accelerations are multiplied by the M of the test device to determine the inertial head forces
20、. The directions of these inertial forces are the same as the directions of their corresponding acceleration vectors. 3.8 Neck Forces (Fx, Fy, Fz)The neck forces are determined directly from the load cell, per 3.5, which reads the forces acting on the neck at the location of the load cell (the base
21、of the skull in this case). Fxis longitudinal shear, Fyis lateral shear, and Fzis axial force. Forces (Fx, Fy, Fz) are applied to the neck in this paper (see Figure 1). A positive Fxoutput from the load cell means head rearward motion relative to neck; positive Fyoutput is head left motion relative
22、to neck; and positive Fzoutput is tensile force or head upward motion relative to the neck. Conventions are per SAE J211-1. 3.9 Test Device Any full, partial, or simulated anthropomorphic dummy equipped with head accelerometers and load cell per 3.4 and 3.5 is defined as the test device. For example
23、, the 50th percentile male Hybrid III dummy specified in 49 CFR Part 572, Subpart E, can be used, as can any derivative of that dummy with proper instrumentation. 4. DATA ACQUISITION AND PROCESSING SYSTEM The data acquisition and processing system must be capable of supplying transducer data per SAE
24、 J211-1 which recommends that both head acceleration and neck force utilize channel class 1000, and that any multiple recording devices are time-referenced per 4.4.2 of SAE J211-1. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted
25、 without license from IHS-,-,-SAE J2052 Revised JAN2011 Page 4 of 6FIGURE 1 - HEAD CONTACT DURATION ANALYSIS - ACCELERATION AND FORCE 5. PROCEDURE FOR DETERMINING HEAD CONTACT DURATION (te, td)The subject method uses Equation 2: (Eq. 2) The acceleration components (ax, ay, az) of the head are multip
26、lied by the M to produce the components of inertial head force. Each neck force component (Fx, Fy, Fz) is subtracted from the corresponding calculated inertial head force component. The aforementioned subtractions produce three force-differences. The external resultant head force (F) is calculated b
27、y taking the root sum square of the force-differences, and is plotted as a function of time. This plot represents the resultant contact force acting on the head. In order to establish consistent engagement (te) and disengagement (td) times for each contact, the following method is established: A con
28、tact is assumed to have occurred when the force level has reached 500 N. The tefor this contact is obtained by tracing backwards in time from the 500 N point on the force versus time curve until 200 N is first reached. The tdfor this contact is determined by tracking forward in time until the curve
29、crosses the 200 N force level. A subsequent contact is assumed to have occurred when the force level again has reached 500 N after the first time td.The teand tdfor this second contact are determined in the same manner used for determining teand tdin the previous contact. This process is repeated fo
30、r each subsequent contact, and is illustrated in Figure 2. FMaxFx()2MayFy()2MazFz()2+=Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2052 Revised JAN2011 Page 5 of 6FIGURE 2 - DETERMINATION OF
31、CONTACT DURATIONS FROM CONTACT FORCE-TIME CURVE 6. OTHER INFORMATION 6.1 Maximum Contact HIC The HIC is calculated for each contact interval determined in Section 5. The HIC t1and t2values for each contact interval may be equal to, or within the corresponding te, tdinterval. The maximum contact HIC
32、is the largest HIC value from all the contacts. 6.2 Resultant External Contact Force, F, and Its Direction (x, y, z)The procedure in Section 5 allows the calculation of the actual contact force (which is the peak force shown in Figure 2). The direction of that force can be obtained by Equations 3 th
33、rough 5: (Eq. 3) (Eq. 4) (Eq. 5) where: x, y, and zare the direction cosine angles of the resultant external contact force, F. x1MaxFxFcos=y1MayFyFcos=z1MazFzFcos=Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license f
34、rom IHS-,-,-SAE J2052 Revised JAN2011 Page 6 of 67. NOTES 7.1 Marginal Indicia A change bar (l) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editorial changes, have been made to the previous issue of this document. An (R) symbol to th
35、e left of the document title indicates a complete revision of the document, including technical revisions. Change bars and (R) are not used in original publications, nor in documents that contain editorial changes only. PREPARED BY THE SAE SAFETY TEST INSTRUMENTATION STANDARDS COMMITTEE Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
