SAE J2422-1998 Cab Roof Strength Evaluation.Quasi-Static Loading Heavy Trucks.pdf
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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 therefr
2、om, 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. QUESTIONS REGARDING THIS DOCUMENT: (724) 772-8512 FAX: (724) 776-0243 TO PLACE A DOCU
3、MENT ORDER; (724) 776-4970 FAX: (724) 776-0790 SAE WEB ADDRESS http:/www.sae.org Copyright 1998 Society of Automotive Engineers, Inc. All rights reserved.Printed in U.S.A. SURFACE VEHICLE 400 Commonwealth Drive, Warrendale, PA 15096-0001 RECOMMENDED PRACTICE Submitted for recognition as an American
4、National Standard J2422 ISSUED JAN1998 Issued1998-01 Cab Roof Strength EvaluationQuasi-Static Loading Heavy Trucks 1.ScopeThis SAE Recommended Practice describes the test procedures for conducting quasi-static cab roof strength tests for heavy-truck applications. Its purpose is to establish recommen
5、ded test procedures which will standardize the procedure for heavy trucks. Descriptions of the test set-up, test instrumentation, photographic/video coverage, and the test fixtures are included. 2.References 2.1Applicable PublicationsThe following publications form a part of the specification to the
6、 extent specified herein. Unless otherwise indicated the latest revision of SAE publications shall apply. 2.1.1SAE PUBLICATIONSAvailable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001. SAE J211-1Instrumentation for Impact TestPart 1: Electronic Instrumentation SAE J211-2Instrumentation
7、for Impact TestPart 2: Photographic Instrumentation SAE CRP-9“Heavy Truck Crashworthiness (Statistics, accident Reconstruction, Occupant Dynamics Simulation)“, March 1995. SAE CRP-13“Heavy Truck Crashworthiness (Phase III),“ April 1997. 3.Definitions 3.1PlatenA structurally stiff, flat plate. 3.2Cab
8、 MountThe component or components used to connect the cab to the chassis frame rails. 3.3Static Stability PositionThe roll position at which a vehicle would be statically balanced on either left- or right-side wheels. 4.Test ConfigurationThe cab roof strength test is designed to evaluate the resista
9、nce 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 degrees, and a quasi-static roof loading that simulates the loading on the cab when the vehicle is inverted. Both
10、 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-loading is generated from the inertia of the plate and the structure carrying it. To assist with the description of
11、 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. SAE J2422 Issued JAN1998 -2- FIGURE 1REFERENCE FRAME 5.Dynamic Pre-LoadIn the dynamic pre-load, the platen impa
12、cts 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 axis. Either side of the cab may be loaded, depending on whether a driver side or passeng
13、er 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 of travel of the platen. The pre-load configuration is shown in Figure 2. The target spe
14、ed of the platen and its supporting structure is computed as described in the following sections. FIGURE 2DYNAMIC PRE-LOAD CONFIGURATION 5.1Pre-Load Energy ComputationThe energy to pre-load the cab comes from the kinetic energy of the platen and its supporting structure. For the pre-load phase of th
15、e test, the target energy 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 accident
16、s. Manufacturers can, at their 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. The calculatio
17、n assumes that all the potential energy at the static stability position is converted to kinetic energy at the ground contact 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 followi
18、ng sections in determining the platen impact speed. SAE J2422 Issued JAN1998 -3- (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
19、of gravity 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 FIGURE 3STATIC STABILITY POSITION TWc TWFTWR+() 2 - - hN TWc 2 - - 2 hcg2+ hF
20、 TWctw+() 2 - KEmghNhF()= = = = SAE J2422 Issued JAN1998 -4- FIGURE 490-DEGREE ROLL POSITION 5.2PlatenA 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 t
21、he platen, not the outer edge. The face of the platen is to be 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
22、 the platen are described in the following sections. 5.3Carriage OptionWith 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 stabil
23、ize it and obtain the target mass. The platen impact speed to obtain the desired pre-load energy level is computed with Equation 2. (Eq. 2) where: M= Mass of the platen and carriage C= Multiplication factor, 1.6 VPL= Target speed for the pre-load test 5.4Pendulum OptionWith this option, the platen i
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