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 theref
2、rom, 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 2010 SAE International All rights reserved. No part of this publication ma
3、y 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: 724-776-4970 (outside USA)
4、Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/J2422_201002SURFACEVEHICLERECOMMENDEDPRACTICEJ2422 FEB2010 Issued 1998-01 Revised 2010-02 Supersed
5、ing J2422 DEC2003 Cab Roof Strength EvaluationQuasi-Static Loading Heavy Trucks RATIONALEAdded the option to use a more readily available manikin when assessing the test cab intrusion into the occupant survival space. The new manikin options are very similar to the current ECE regulation requirement
6、 and will have no signification affect on the result of the assessment. 1. SCOPE This SAE Recommended Practice describes the test procedures for conducting quasi-static cab roof strength tests for heavy-truck applications. Its purpose is to establish recommended test procedures which will standardiz
7、e the procedure for heavy trucks. Descriptions of the test set-up, test instrumentation, photographic/video coverage, and the test fixtures are included. 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this specification to the extent specified herein. Unless otherwi
8、se indicated, the latest issue of SAE publications shall apply. 2.1.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org.SAE J211-1 Instrumentation for Impact TestP
9、art 1Electronic Instrumentation SAE J211-2 Instrumentation for Impact TestPart 2Photographic Instrumentation SAE J826 Devices for Use in Defining and Measuring Vehicle Seating Accommodation SAE J1516 Accommodation Tool Reference Point SAE CRP-9 “Heavy Truck Crashworthiness (Statistics, accident Reco
10、nstruction, Occupant Dynamics Simulation),“ March 1995 SAE CRP-13 “Heavy Truck Crashworthiness (Phase III),“ April 1997 SAE J2422 Revised FEB2010 Page 2 of 82.1.2 Other Publications ECE Regulation 29: Uniform Provisions Concerning the Approval of Vehicles with Regard to the Protection of the Occupan
11、ts of the Cab of a Commercial Vehicle. 3. DEFINITIONS 3.1 Platen A structurally stiff, flat plate. 3.2 Cab Mount The component or components used to connect the cab to the chassis frame rails. 3.3 Static Stability Position The roll position at which a vehicle would be statically balanced on either l
12、eft- or right-side wheels. 4. TEST CONFIGURATION The cab roof strength test is designed to evaluate the resistance of a heavy-truck cab in 180-degrees rollover. The loading is divided into two phases, a dynamic pre-load that simulates the side loading on the upper cab as the vehicle rolls past 90 de
13、grees, and a quasi-static roof loading that simulates the loading on the cab when the vehicle is inverted. Both phases are conducted on a cab attached to actual or simulated frame rails with its standard cab mounts. The loading is applied to the cab with a platen. The energy for the dynamic pre-load
14、ing is generated from the inertia of the plate and the structure carrying it. To assist with the description of the platen orientation and direction of motion, a reference system is defined for the cab and chassis relative to its original orientation on the vehicle. This is illustrated in Figure 1.
15、FIGURE 1 - REFERENCE FRAME 5. DYNAMIC PRE-LOAD In the dynamic pre-load, the platen impacts one side of the cab, with the cab mounted at an angle so that the platen initially contacts the upper portion of the cab. The platen is oriented vertically, and aligned parallel to the chassiss longitudinal ax
16、is. Either side of the cab may be loaded, depending on whether a driver side or passenger side leading rollover is to be simulated. The chassis of the test cab shall be affixed to the ground at a roll angle of 20 degrees. The longitudinal axis of the chassis shall be perpendicular to the direction o
17、f travel of the platen. The pre-load configuration isshown in Figure 2. The target speed of the platen and its supporting structure is computed as described in the following sections. SAE J2422 Revised FEB2010 Page 3 of 8FIGURE 2 - DYNAMIC PRE-LOAD CONFIGURATION If the cab or its mounting is not sym
18、metric, such that it may result in a strong or weak side, the weak side of the assembly should be evaluated. 5.1 Pre-Load Energy Computation The energy to pre-load the cab comes from the kinetic energy of the platen and its supporting structure. For the pre-load phase of the test, the target energy
19、level is 1.6 times a reference energy level up to a maximum recommended target level of 17 625.6 J (13 000 ft-lb). The recommended maximum is based upon the limited testing performed to evaluate this test procedure and to produce cab damage consistent with rollover accidents. Manufacturers can, at t
20、heir discretion, exceed this maximum. The reference energy level is an approximation of the kinetic energy developed when a vehicle is tipped from its static stability position to a rest position on its side. Both positions are illustrated in Figures 3 and 4. Thecalculation assumes that all the pote
21、ntial energy at the static stability position is converted to kinetic energy at the groundcontact point. Basic dimensions, weight, and the center of gravity (cg) height of the vehicle are needed for this calculation. This computed energy level shall be used in the following sections in determining t
22、he platen impact speed. TWcTWFTWR+()2-hNTWc2-2hcg2+hFTWctw+()2-KE mghNhF()=(Eq. 1) where:TWF= Trackwidth of front wheels TWR= Trackwidth of the rear wheels, in the case of dual wheels, use the outermost wheels TWc= Trackwidth representation at the cg location tw = Tire tread width hcg= Center of gra
23、vity height of level vehicle hN= Height of the cg at the static stability position hF= Height of the cg at the ground contact position KE = Reference kinetic energy level TE = Target impact energy mg = Weight of vehicle SAE J2422 Revised FEB2010 Page 4 of 8FIGURE 3 - STATIC STABILITY POSITION FIGURE
24、 4 - 90-DEGREE ROLL POSITION 5.2 Platen A rigid platen shall be used to simulate ground contacting the side of the cab. The platen shall be sufficiently large and positioned such that the cab will only be in contact with the interior of the platen, not the outer edge. The face of the platen is to be
25、 covered with a 19 mm (3/4 in) thick layer of plywood. For the dynamic pre-load phase of the test, the platen and structure that carries it shall have a mass of 2268 to 6803.9 kg (5000 to 15 000 lb). Two recommended methods for supporting the platen are described in the following sections. 5.3 Carri
26、age Option With this option, the platen is attached to the front of a carriage. The carriage is then towed to a target impact speed and released to roll into the cab. Ballast shall be added as necessary to the rear of the carriage to stabilize it and obtain the target mass. The platen impact speed t
27、o obtain the desired pre-load energy level is computed with Equation 2. VPL2CKEM-=(Eq. 2) where:M = Mass of the platen and carriage C = Multiplication factor, 1.6 VPL= Target speed for the pre-load test SAE J2422 Revised FEB2010 Page 5 of 85.4 Pendulum Option With this option, the platen is attached
28、 to a pendulum. The pendulum is then pulled back to a height determined to obtain the target impact speed and released to swing into the cab. Ballast shall be added as necessary to the pendulum to reach the target mass. The pendulum should be positioned relative to the cab so that the platen is vert
29、ical at impact. The distance from the bottom of the platen to the pivot point should be at least 610 cm (20 ft) to ensure that there is relatively little vertical motion of the platen during the crush phase of the test. This will also ensure that the platens orientation remains nearly vertical throu
30、ghout the impact. The platen impact speed to obtain the desired pre-load energy level is computed from the following equations. With a simple pendulum, the system has rotational as well as linear kinetic energy. All of the kinetic energy can be accounted for with a simple computation if the moment o
31、f inertia is calculated at the pivot axis. PL2CKEJPIVOT-=(Eq. 3) where:JPIVOT= Moment of inertia of pendulum and platen about the pivot axis C = Multiplication factor, 1.6 PL= Target rotational speed for the pre-load test For comparison purposes, the impact speed should be computed as the pendulum s
32、peed at the mid-height of the cab side window. VPLRPL=(Eq. 4) where:R = Vertical distance from the pivot axis to the mid-height of the side window VPL= Target speed for the pre-load test A bifilar pendulum design may be used to constrain the platen in a vertical orientation. For a bifilar pendulum,
33、the arms of the pendulum have rotational kinetic energy, but the mass at the end of the pendulum, including the platen, only has linear kinetic energy. VPL2CKEMnJARML2+-=(Eq. 5) where:M = Mass at the end of the bifilar pendulum, including the platen, ballast, and supporting structure JARM= Moment of
34、 inertia of pendulum arms about the pivot axis L = Length of each arm from the upper to the lower pivot n = Number of pendulum arms C = Multiplication factor, 1.6 VPL= Target speed for the pre-load test SAE J2422 Revised FEB2010 Page 6 of 86. QUASI-STATIC ROOF LOAD In this phase, a platen that is pa
35、rallel to the xy plane of the chassis is loaded into the roof of the cab. The platen moves parallel to the vertical axis of the chassis. This can be implemented by affixing the chassis to ground, with it rotated so that the longitudinal axis of the chassis is horizontal and the lateral axis is verti
36、cal. With the side of the cab that was impacted in the pre-load phase oriented downward, a vertical platen would then travel horizontally into the roof. This roof loading configuration is shown in Figure 5. Another possible implementation is with the chassis mounted with its longitudinal and lateral
37、 axes horizontal, with the platen traveling in the vertical direction. 6.1 Platen A rigid platen shall be used to simulate ground contacting the roof of the cab. The platen must be sufficiently large and positioned such that the cab will contact only the interior of the platen, not the edges. A line
38、ar bearing system shall be included between the platen and its supporting structure to allow for lateral motion of the cab roof away from the side that was impacted in the pre-load phase. In the recommended configuration described previously, the platen weight would tend to oppose this motion, thus
39、the weight must be less than 25% of the chassis cab vehicle.FIGURE 5 - QUASI-STATIC ROOF LOAD CONFIGURATION 7. CAB MOUNTING The cab shall be evaluated with its standard cab mounts. The cab mounts shall either be mounted to the vehicles stock frame rails or to a simulated chassis that locate the cab
40、mounts in their standard location and orientation. If testing is conducted using actual frame rails, the frame rails shall be rigidly attached to the ground. If a simulated chassis is used, itshall not deform during the test. Hardware used to attach the cab mounts to the simulated chassis shall be t
41、he same type and strength as the standard hardware used to attach the cab mounts to the standard chassis. Cab mounts employing pneumatic ride control should be pressurized to produce the manufacturer recommended ride height.If the vehicle always includes a body or other structural member that will i
42、nfluence the cabs motion, the body or structure may be included on the simulated chassis. Care should be taken to insure that only the structural members always on the vehicle provide the load path to ground. Unless specifically identified, such as the vertical roof load platen conditions, the test
43、fixtures should not influence the motion of the vehicles standard equipment. SAE J2422 Revised FEB2010 Page 7 of 88. INSTRUMENTATION To record the load applied to the cab structure, load cells shall be installed between the platen and its supporting structure. For the dynamic pre-load phase, the mea
44、sured load must be scaled to obtain the load applied to the cab as follows: FCABFMEASUREDWTOTALWSUPPORT-=(Eq. 6) where:FCAB= Load applied to the cab FMEASURED= Measured load WTOTAL= Combined weight of the platen and supporting structure WSUPPORT= Total weight minus the platen weight The displacement
45、 of the platen shall also be measured and recorded. For the dynamic pre-load phase, one method for measuring platen motion is to attach accelerometers to the platen or supporting structure. Displacement of the platen during the crush phase of the test is determined by twice integrating the accelerat
46、ion data. All measurements should be recorded and filtered according to the most recent version of SAE J211-1 and SAE J211-2. To quantify the amount of intrusion of the roof into the occupant compartment during the quasi-static roof loading phase, displacement of the roof perpendicular to the cab fl
47、oor should be measured. The recommended locations for the measurement are nominally at the driver and passenger seating locations. Any other locations of potential interest for cab intrusion should also be measured. 9. PHOTOGRAPHIC DOCUMENTATION For the dynamic pre-load phase, high-speed film or vid
48、eo cameras are recommended. Each camera should have provision for recording a time reference (timed pulse signal for film cameras) and should have an exposure rate sufficient to facilitate motion analysis. Exposure rates of 200 to 1000 frames per second are acceptable. Real-time film or video cameras are recommended for the quasi-static roof loading phase. The field of view of these cameras should be large enough to document the entire cab throughout the test. Provisions should be made for synchronizing electronic
