1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW16693 Multi-axis Seat Subsystem Durability Test Copyright 2013 General Motors Company All Rights Reserved February 2013 Page 1 of 11 1 Scope Note: Nothing in this standard supercedes applicable laws and regulations. Note: In the event of conflict be
2、tween the English and domestic language, the English language shall take precedence. 1.1 Purpose. This procedure evaluates the structural durability of a front or rear seat subsystem by subjecting it to real time load and displacement profiles. These profiles are designed and developed to represent
3、a lifetime usage. This procedure describes the durability test execution. 1.2 Foreword. 1.2.1 This procedure is primarily intended for laboratory test engineers and technicians. It does not cover every possible aspect of durability testing and is not to be used as a stand-alone procedure. Successful
4、 durability testing inherently requires engineering judgment and the ability to recognize and solve problems which are unexpected and/or complex. 1.2.2 This procedure utilizes a generic profile developed from Road Load Data Acquisition (RLDA or vRLDA), drive file development and correlation evaluati
5、on. The time required has been reduced by utilizing the damage cycles of a typical seat system and is provided in the appropriate Subsystem Technical Specification (SSTS) or Component Technical Specification (CTS). However, if a new architecture is developed, a new profile can be developed. 1.3 Appl
6、icability. This procedure applies to all free standing seats or partially free standing seats for GM passenger cars, Sport Utility Vehicles (SUV) and light and medium duty trucks. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/
7、Specifications. None 2.2 GM Standards/Specifications. GMW15219 GMW15245 2.3 Additional References. Component Technical Specification Subsystem Technical Specification 3 Resources 3.1 Facilities. A bedplate large enough for securing the test rig and capable of withstanding dynamic loading of the test
8、 rig/specimen required. Also required is a hydraulic system capable of supplying oil at a rate consumed by a Multi-axial Simulation Table (MAST). The test facilities and equipment shall be in good working order and all instrumentation shall have a valid calibration label. 3.1.1 Calibration. The test
9、 facilities and equipment shall be in good working order and shall have a valid calibration label. 3.1.2 Alternatives. Alternative test facilities and equipment may also be used. However, all measuring variables as specified in this standard shall be determined correctly with respect to their physic
10、al definition. 3.2 Equipment. Note: The following list(s) include test rig, fixtures and transducers typically used by the GM Structural Development Laboratory to perform this test. Other equipment may be substituted at the discretion Copyright General Motors Company Provided by IHS under license wi
11、th General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16693 Copyright 2013 General Motors Company All Rights Reserved February 2013 Page 2 of 11 of the local testing facility, as long as it provides the same
12、data and/or data record with equivalent accuracy as specified herein or by the requestor. 3.2.1 Test Rig. A simulation table capable of controlling 3 degrees of freedom, (vertical, lateral, and fore-aft). Also a multi-axis table with 6 degrees of freedom can be used. A typical MAST table in current
13、usage at GM with 3 degrees of freedom is shown in Figure A1. Alternative test equipment is also shown in Figures A2 and A3. 3.2.1.1 The simulation table surface area should be adequate to mount the test specimen and the appropriate fixtures. The hydraulic actuators should be sized appropriately to r
14、eproduce the acceleration as provided in the SSTS. 3.2.1.2 Fixtures. Fixturing is required to support the test specimen in its test position. 3.2.1.2.1 Fixture for Front Seats. A means to support the front seat system including rigid mounting blocks, or equivalent, simulating the floor attachment po
15、ints to mount the seat system in the test position on the MAST. A typical fixture for front seat subsystems is shown in Appendix B, Figure B1. 3.2.1.2.2 Fixture for Rear Seats. A means to support the rear seat system including rigid mounting blocks, or equivalent, simulating the attachment points to
16、 the vehicle. A fixture simulating the body is used for rear seat subsystems. 3.2.1.3 Loads. Loads as required in the SSTS to be added to the seat during durability testing. If no weight is specified, then the following default weights may be utilized. This test can also evaluate the seat in the fol
17、d down position with weights of 10 kg as shown in Appendix D, Figures D1 and D2. 3.2.1.3.1 Dummy. Dummy to simulate occupant of a 95% (90 kg) for outboard positions, and 50% (70 kg) for center. Typically water dummies with the approximate weights are utilized. 3.2.2 Transducers. 3.2.2.1 Acceleromete
18、r. Accelerometers are used to match the acceleration data that is provided in the SSTS or CTS as specified. The default accelerations in Appendix B, Table B1 may be utilized if approved by the GM responsible engineer. Remote parameter response coherent with the given direction for each actuator is r
19、equired for each of the hydraulic actuators controlling the motion of the table. Acceleration responses must be collected on the rigid body and/or frame side as required. It is important to insure that there are not additional accelerations being generated by less than robust attachment to structure
20、. 3.2.2.1.1 Loads/Strains. Loads and strains on the specimen can be used in a non-square matrix as additional control channels or for correlation. 3.2.2.1.2 Torque Wrench. A torque wrench is used to tighten all threaded fasteners to the specified torque. 3.3 Test Vehicle/Test Piece. Complete trimmed
21、 seat subsystem in the heaviest version. An appropriate seat subsystem consisting of all components necessary to qualify as complete for the model and trim level specified by the Design Release Engineer. This test can be completed on seat structure only by massing out the structure to represent the
22、missing components and simulating the center of gravity of a trimmed seat. 3.4 Test Time. The following is an estimate of the amount of time (work hours) needed to perform this procedure. Note: These time estimates are approximate averages. Actual times vary considerably depending on early component
23、 failures (and subsequent availability of replacement parts), testing to varying multiples of cycle lives, scheduling problems for test facilities, test equipment malfunctions, scheduling of overtime and/or multiple shifts, actual readiness of test samples upon receipt, unique or additional requests
24、 for detailed test information, running multiple samples (times shown are for one sample), etc. The reported times consider preparation and other downtime, actual test, and analysis of data in capturing a total calendar time. They are estimated ranges for a typical durability test and will vary base
25、d upon the chosen durability schedule. Report writing, approval, processing, etc., are not part of the reported times. Calendar time: 9 to 15 days Test hours: 70 to 120 hours Coordination hours: 1 to 8 hours 3.5 Test Required Information. The requesting engineer is responsible for identifying the du
26、rability schedule to be simulated and provide test specifications, SSTS or CTS paragraph numbers, appropriate to the component/subsystem being tested. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted witho
27、ut license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16693 Copyright 2013 General Motors Company All Rights Reserved February 2013 Page 3 of 11 3.5.1 Time History Data. RLDA data should be provided to the test lab in Remote Parameter Control (RPC) III format. File names must adhere to the l
28、ocal standard naming convention (reference GMW15219 for the appropriate file naming convention). Modifications to the provided data should be documented in the RLDA report. 3.5.2 Durability Part Information. Part numbers, design level, Uniform Part Classification (UPC) codes, Functional Name Address
29、 (FNA) codes, etc., must be provided for the production intent material to be evaluated during the test. Fastener torque specifications must be provided along with assembly sequences that may apply to properly assemble the test specimen. 3.5.3 Test Inspections. The minimum lab practice is to inspect
30、 the test specimen three times per 8 h shift during durability testing. Any increase in inspection frequency should be specified by the requester at the start of durability testing. 3.6 Personnel/Skills. Prior experience/training in setting up and running similar tests and experience/training in the
31、 use of the referenced test equipment are required for a successful evaluation. This experience is also critical to achieving the estimated times shown in 3.4. 4 Procedure 4.1 Preparation. 4.1.1 Test Profiles. The profiles are to be obtained from the CTS or SSTS. 4.1.2 Test Development. The goal in
32、test development is to reproduce the system response measured on the road during the RLDA. The input files are provided in the CTS and SSTS; if there is none provided, then the default inputs can be utilized from Table B1 in Appendix B. The default time for the generic profile is 67 h. 4.1.2.1 Inspe
33、ct Hardware. The seat structure hardware should be inspected upon receipt. Ensure that all hardware needed to develop the test has been provided or is available at the test site. 4.1.2.1.1 Perform Instrumentation Checks. Prior to assembly, perform a function check of the transducers. Connect the tra
34、nsducers to the instrumentation and perform standard balance, calibration, and polarity checks. 4.1.2.2 Prepare Test Development Specimen. The test and requesting engineers should inspect the specimen to insure all material listed in 3.3 is of correct design level and assembled properly for test dev
35、elopment. Obtain approval from the requester utilizing local test lab approval documents. 4.1.2.2.1 Installation of Seat into Fixture. Install the seat subsystem on the MAST table with a suitable fixture which simulates the seat attachments to the vehicle. 4.1.2.2.2 Prepare Test Development Specimen
36、. If a new test development specimen has to be prepared, the test requester has to provide the necessary measurement positions. The measurement positions, sensor type and settings are listed in the final report. Place accelerometers at the attachment areas of the seat subsystem. The acceleration inp
37、uts are to be verified. Once there is verification of the inputs, the test may be started. The placement of transducers or sensors is shown in Figures C1, C2, C3, C4 and C5 and can be utilized to measure the response of the inputs. 4.1.2.3 During the Test. The Test Site Controller (TSC) is used to c
38、ontrol the test rig and the instrumentation associated with the test specimen. System response is collected using the RLDA hardware on the test rig in conjunction with the TSC. The TSC, running RPC programs, is used to manipulate data in the time and frequency domains allowing the creation of test r
39、ig drive files that are used to control the motion of the test rig. 4.1.2.3.1 Calculate Frequency Response Function. Test rig drive file development begins with calculating a Frequency Response Function (FRF) for the test rig system. The FRF is a matrix math model that describes the relationship (am
40、plitude and phase) of the inputs (test rig drives) specified frequency band. The inverse FRF is used to estimate/correct the test rig drives over the specified frequencies. The typical frequency control band for the simulation table drive is 0.4 to 50 Hz. The FRF must encompass all frequencies in th
41、e control band. When establishing the control band for the test rig, consider actuator displacement limitations and test rig/fixture resonance. 4.1.2.3.2 Iterate Test Rig Drive Files. Test rig drive file development continues through an iterative process utilizing the FRF. An initial test rig drive
42、is estimated based upon the desired RLDA response and the relationship predicted by the FRF for drive and response. The initial drive is played out to the test rig at partial amplitude (gain control) because the FRF is a linear approximation of a non-linear system. A new system response is collected
43、 for the initial drive and compared to the desired RLDA response. The resulting error is Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW
44、16693 Copyright 2013 General Motors Company All Rights Reserved February 2013 Page 4 of 11 used to correct/adjust the initial drive. The new test rig drive is played out and the process is repeated (next iteration). This continues until the system response matches the desired RLDA response. 4.1.2.3.
45、3 Collect Final Response. Upon completion of test rig drive file iterations, a system response corresponding to the final test rig drive must be collected for correlation purposes. The system final response(s) should include all test rig and system transducers. 4.1.2.3.4 Archive Data. The test rig r
46、esponse and drive files should be preserved for future reference (in the event that the test must be reproduced at a later date). Archive test development data per local laboratory practice. 4.1.2.4 Test Development from Test Rig Responses. When attempting to recreate a previous test, or if a change
47、 has been made to the test rig, test rig drive files may need to be adjusted. The process of developing test rig drive files in this manner is referred to as iterating test rig drive files to test rig responses. 4.1.2.4.1 Develop the Test. This process is the same as specified in 4.1.2.3 with one ex
48、ception. The desired response referenced in 4.1.2.3.2 is a test rig response collected from a prior test development, rather than an RLDA response. Test correlation, as specified in 4.1.2.3.4, will be to the prior test rig response (or an original remote parameter) rather than the road baseline. 4.1
49、.2.5 Time and Pseudo Damage Optimization. The target test time for the typical durability test is approximately 70 to 120 h. Pseudo damage retention targets are specified in GMW15245. If the specified targets have not been achieved for time and pseudo damage retention, consult the local test expert/mentor for assistance. Note: Multiplier optimization is the process by which the prescribed test module repeats are manipulated in the interest of saving time. It is also used to increase or decre
