SAE ARP 1328C-2017 Aircraft Ground Support Equipment - Wind Stability Determination.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 ther

2、efrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2017 SAE International All rights reserved. No part of this

3、publication may 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: +1 724-776-49

4、70 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/standards.sae.org/ARP1328C AEROSPACE RECOMMENDED PRACTICE ARP1328 REV. C Issued 1974-03 Reaffirmed 2012-10 Revis

5、ed 2017-05 Superseding ARP1328B Aircraft Ground Support Equipment - Wind Stability Determination RATIONALE Correction of formulae in English units. Minor editorial updates. 1. SCOPE 1.1 Purpose This SAE Aerospace Recommended Practice (ARP) is intended to recommend: a. uniform criteria for determinat

6、ion of wind loads that aircraft ground support equipment can encounter and yet allow personnel to work safely, b. uniform systems for maintaining stability (i.e., stabilizers, outriggers, spring lockout devices), c. standardization of specific types of interlock systems and actuation systems, d. a s

7、tandard formula with its associated design criteria for calculating the steady-state wind stability (i.e., tip point) for aircraft ground support equipment, e. a standard method for testing these systems. 1.2 Field of Application This document is intended to be applicable to mobile self-propelled or

8、 not self-propelled Ground Support Equipment (GSE) to be used for directly servicing transport aircraft. It is not intended to apply to the following equipment: a. ladders, stands, and scaffoldings not used as GSE to directly service an aircraft, b. airport passenger boarding bridges, c. any fixed f

9、acility or part thereof, d. fire fighting equipment. SAE INTERNATIONAL ARP1328C Page 2 of 9 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other p

10、ublications shall be the issue in effect on the date of the purchase order. In the event of conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a speci

11、fic exemption has been obtained. 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 +1 724-776-4970 (outside USA), www.sae.org. AIR1375 Minimum Safety Requirements for Special Purpose Airline Ground

12、 Support Equipment 2.1.2 U.S. Government Publications Copies of these documents are available online at http:/quicksearch.dla.mil. Title 29 CFR Part 1910 Occupational Health and Safety Administration (OSHA) 2.1.3 ISO Publications Copies of these documents are available online at http:/webstore.ansi.

13、org/. ISO 11995:1996 Aircraft - Stability requirements for loading and servicing equipment 2.1.4 European Standards Available from CEN, Comite Europeen de Normalisation, rue de Stassart 36, B1050 Brussels, Belgium, or any of the European national standardization institutes, members of CEN. EN 1915-2

14、:2001 Aircraft ground support equipment - General requirements - Part 2: Stability and strength requirements, calculations and test methods NOTE: Applicable to equipment to be operated in Europe, as one recognized means to demonstrate compliance with the E.U. Machinery Directive. 2.1.5 IATA Publicat

15、ions Available from International Air Transport Association, Publications Assistant, 800 Place Victoria, P.O. Box 113, Montreal, Quebec H4Z 1M1, Canada, Tel: 1-514-874-0202, www.iata.org. Airport Handling Manual AHM 913 Basic safety requirements for aircraft Ground Support Equipment SAE INTERNATIONA

16、L ARP1328C Page 3 of 9 2.2 Definitions 2.2.1 JET BLAST The equivalent of a wind gust produced by the jet engines of an aircraft. 2.2.2 OUTRIGGERS Stabilizer devices used to improve the stability of vehicles, applied within the envelope of the vehicle. 2.2.3 STEADY-STATE WIND A wind which produces a

17、constant force. 2.2.4 VEHICLE INSTABILITY Deflection of vehicle due to a wind force, causing unsafe working conditions. 2.2.5 VEHICLE TIP POINT Maximum vehicle instability where the vehicle center of gravity has been rotated by a wind force to a point directly above the vehicle pivot point. 2.2.6 VE

18、HICLE PIVOT POINT That point of the vehicle in contact with the ground on the opposite side of the vehicle from the side to which the wind force is applied and furthest from the winds application point. 2.2.7 WIND Movement of air which causes a force to be imposed on surfaces of aircraft ground supp

19、ort equipment. 2.2.8 WIND GUST A temporary increased wind force that exceeds the steady-state wind force. 3. STABILITY INCREASE SYSTEMS 3.1 Integral Vehicle Chassis Methods 3.1.1 Heavy-Duty Springs and Auxiliary Overload Springs These produce a harder ride, but provide increased side movement stabil

20、ity and assist in leveling off-center loads when the vehicle is moving or stationary 3.1.2 Heavy-Duty Shock Absorbers These produce a harder ride but provide increased side movement stability while the vehicle is moving. 3.1.3 Tire Pressure High tire pressure on a vehicle increases the overall stabi

21、lity of either a slow moving or stationary vehicle but produces a harder ride. SAE INTERNATIONAL ARP1328C Page 4 of 9 3.1.4 Torsional Stabilizer Bar Systems These increase stability by reducing chassis movement through a rigid bar or spring and can be applied in several areas of the chassis. These s

22、ystems do not adversely affect the ride of the vehicle as much as those in 3.1.1, 3.1.2, 3.1.3, and 3.1.5. 3.1.5 Spring Lockout Systems These block out the chassis springs against the axle and improve the stationary stability of a vehicle. Spring lockouts should not be engaged while a vehicle is mov

23、ing as this produces an extra hard ride and transmits all road shocks directly into the vehicle structure. 3.2 Stabilizer Jacks and Stabilizer Systems These systems generally utilize hydraulic cylinders of manually operated structural devices with self-leveling or fixed foot pads that press against

24、the ground within the envelope of the vehicle. These systems stabilize the vehicle chassis when it is stationary by blocking out chassis movement on the springs and tires. Usually, stabilizer jacks are used in tandem (one on each side of the vehicle) and placed at various key positions along the len

25、gth of the vehicle. Two or more can be used as required. 3.3 Outrigger Systems These systems generally utilize hydraulic cylinders or manually operated structural devices that extend self-leveling or fixed foot pads to the ground beyond the normal envelope of the vehicle with heavy structural member

26、s that are connected to the chassis. The farther out from the chassis that these foot pads are extended, the greater the resistance to tipping. Generally, a combination of some of the above mentioned systems will be utilized to gain the desired stability and firmness of ride. The choice of these sys

27、tems is left up to the designer because every vehicle is different in design and function. 4. INTERLOCK AND ACTUATION SYSTEMS The use of interlock and actuation systems partially depends upon the quality and capabilities of the personnel that will be operating the vehicle. It is also advisable to ha

28、ve interlock devices on the outrigger and stabilizer systems that are depended upon for providing the safe working conditions for personnel. Normally, hydraulic power will be used to actuate stabilizers and outriggers, although use of electrical or manual means is possible in some cases. These outri

29、ggers and stabilizer interlocks should consist of lock valves at the base of each cylinder to keep the cylinders from retracting if a hydraulic line failure should occur. When actuating the outriggers or stabilizers, the operator should be located in a position where he/she can see the foot pads bei

30、ng extended. This strategic positioning of the actuation system will help avoid accidents and will assure the operator that the outriggers or stabilizers are fully extended or retracted as required. Depending on customer requirements, interlocks may be provided for any of the following functions: a.

31、 Prevent operation of lift systems until stabilizing devices are fully extended. b. Prevent retraction of stabilizing devices until the lift system is full down or below predetermined safe height without stabilizing devices in operation. c. Mechanically or electrically prevent the unit from being dr

32、iven with the stabilizing devices extended. d. Provide visual indication, such as a flashing light, visible from the drivers position to show that the stabilizing devices are extended and/or retracted. SAE INTERNATIONAL ARP1328C Page 5 of 9 5. STANDARDIZED FORMULA FOR CALCULATING STEADY-STATE WIND S

33、TABILITY (TIP POINT) The formula is applicable to all aircraft Ground Support Equipment. Assumptions: a. The formula is applicable to the vehicles projected areas in its worst operating condition where stability is involved. This generally occurs when vehicle is at full extension and is unloaded. b.

34、 The air density is assumed to be 1.20 kg/m3 (0.07528 lb/ft3), standard temperature of 20 C (68 F) and pressure of 101.3 kPa (14.696 psi). If extreme temperatures and pressures must be allowed for, the wind force should be corrected in proportion to the density. c. Wind velocity in km per hour (km/h

35、) or miles per hour (mph) is considered as a steady-state wind condition. Aircraft jet blasts will also be considered as a steady-state wind condition; however, they are likely to produce higher effective forces on the vehicle due to their dynamic nature. Standard formula for calculating the tip poi

36、nt of the vehicle: MO = MR (Eq. 1) where: MO = total overturning moment in N.m (lb-ft) MR = total restoring moment in N.m (lb-ft) Overturning moment formula: MO = 0.0484 V2=n1iiiiCHS in SI (metric units), or (Eq. 2) MO = 0.00252 V2=n1iiiiCHS in inch-pound units (Eq. 2) where: MO = total overturning

37、moment in N.m (lb-ft) V = wind velocity in km/h (mph) (see Figure 1) Si = area of ithelement in m2(ft2) (see Figure 1) Hi = height from ground level of center of area of ithelement in m (feet) (see Figure 1) Ci = shape factor of ithelement based on aspect ratio abin Figure 2 n = number of elements o

38、f sail area with wind loading (i.e., vehicle chassis, vehicle scissor lift system, vehicle body, vehicle boom, etc.) SAE INTERNATIONAL ARP1328C Page 6 of 9 Restoring moment formula: MR = W.d (Eq. 3) where: MR = total restoring moment in N.m (lb-ft) W = total weight of the vehicle in N (pounds) d = D

39、istance from the vehicle center of gravity to the vehicle pivot point in m (feet) as in Figure 3. As a wind force is applied to the side of a vehicle, the vehicle center of gravity is caused to move in the direction of the wind force. For this reason, d should be used as shown in Figure 4. (The cent

40、er of gravity will move due to spring deflection, tire deflection, and structural deflection.) Since: MO = MR (Eq. 4) Then: 0.0484 V2=n1iiiiCHS = W.d in SI (metric) units, or (Eq. 5) 0.00252 V2=n1iiiiCHS = W.d in inch-pound units (Eq. 5) The shape factors so obtained apply to full scale for structur

41、es with sharp edges whose principal resistance is due to the pressure forces. For bodies that do not have any sharp edges perpendicular to the flow, such as spheres or stream-lined bodies, the shape factor CN is not constant. For such bodies, the law for variation of the shape factor CN must be dete

42、rmined experimentally before safe predictions of full-scale forces can be made from model measurements. The force N normal to a flat plate depends upon the aspect ratio A = height/(width) of the plate. Writing N = CN q S, the shape factor CN varies from about 1.18 to 2 as shown in Figure 2. About 70

43、% of normal force on the plate is due to the large underpressures existing over the rear surface. N = CN qS (Eq. 6) where: CN = shape factor based on aspect ration abin Figure 2 q = wind pressure in kPa (lb-ft2) S = area in m2(ft2) SAE INTERNATIONAL ARP1328C Page 7 of 9 Figure 1 Figure 2 SAE INTERNA

44、TIONAL ARP1328C Page 8 of 9 Figure 3 Figure 4 6. STANDARD METHOD FOR TESTING AND PROVING THE TIP POINT (STABILITY) FORMULA 6.1 Application of a chain or cable pulling horizontally at the center of wind pressure of the vehicle. The maximum restoring moment can be determined by measuring the cable ten

45、sion and multiplying that value by the height of application above ground level. Deviations from this method, in order to have practical attachment points, for the testing and proving must be incorporated by re-calculation (e.g., interpolation). 6.2 An air bag can be applied between the vehicle and

46、a solid fixed structure, to simulate the effect of wind loading. The restoring moment can be determined by measuring the static pressure in the air bag, multiplying by the vertical area in contact with the bag, and the height of the center of pressure above ground level. SAE INTERNATIONAL ARP1328C P

47、age 9 of 9 7. NOTES 7.1 Revision Indicator 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 a document. An (R) symbol to the left of the document title indicates a complete revision of the document, including technical revision. Change bars and (R) are not used in original publications, nor in documents that contain editorial changes only. PREPARED BY SAE COMMITTEE AGE-3, AIRCRAFT GROUND SUPPORT EQUIPMENT