1、AIAA R-091-2003 Calibration and Use of Internal Strain- Gage Balances with Application to Wind Tunnel Testing AIAA R-091-2003 Recommended Practice Calibration and Use of Internal Strain- Gage Balances with Application to Wind Tunnel Testing Sponsored by American Institute of Aeronautics and Astronau
2、tics Abstract This document provides a recommended method for calibration of internal strain-gage balances used in wind tunnel testing. The practices include terminology, axis system definition, balance calibration methods, matrix, and documentation. Use of this document will facilitate the exchange
3、 of information among users, suppliers, and other interested parties. AIAA R-091-2003 Library of Congress Cataloging-in-Publication Data Recommended practice : calibration and use of internal strain gage balances with application to wind tunnel testing i sponsored by American Institute of Aeronautic
4、s and Astronautics. p. cm. “R-091-2003.“ Includes bibliographical references and index. ISBN 1-56347-645-2 (Hardcopy) - ISBN 1-56347-646-0 (Electronic) 1 . Wind tunnels-Standards. 2. Strain gages-Calibration-Standards. I. American Institute of Aeronautics and Astronautics. TL567.W5R43 2003 629.13452
5、-dc21 200301 4347 Published by American Institute of Aeronautics and Astronautics 1801 Alexander Bell Drive, Suite 500, Reston, VA 20191 Copyright O 2003 American Institute of Aeronautics and Astronautics All rights resewed. No part of this publication may be reproduced in any form, in an electronic
6、 retrieval system or otherwise, without prior written permission of the publisher. Printed in the United States of America. ii AIAA R-091-2003 Contents Foreword v Dedication vi 1 1 . 1 1.2 1.3 2 2.1 2.2 2.3 2.4 3 3.1 3.2 3.3 3.4 3.5 3.6 4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 5 Introduction 1 Scope 1 Purpose
7、. 1 Cautions and Limitations . 1 Concepts . 2 Forces and Moments 2 Balance Axis System and Moment Reference Center 3 Balance Types . 4 Designated Balance Load Capacity . 6 Calibration 7 Calibration Process . 7 Matrix Determination . 16 Load Calculation Method 18 Transfer of the Calibration Result to
8、 the Test Environment 21 Emerging Technologies 22 Three-Component Balance Example . 25 Calibration Documentation . 40 Matrix File 40 Calibration Report . 45 Calibration Load Envelope 48 Residual Load Error 51 Calibration Statistics 52 Facility Uncertainty 56 Sample Calibration Report 57 Concluding R
9、emarks . 61 . Annex A: Glossary 62 Annex B: References 64 Tables Table 1 . Component Load and Bridge Output Order and Terminology . 4 Table 2 . Bridge Output for Force, Moment, and Direct-Read Balances . 6 Table 3 . Measured Bridge Outputs for the Determination of the Zero Load Outputs 26 AIAA R-091
10、-2003 Table 4 . Calibration Loads and Bridge Outputs 26 Table 6 . Linear Matrix 29 Table 7 . Modified Bridge Outputs for Tare Load Calculation 30 Table 8 . Iteration 1 Tare Loads and Changes . 30 Table 9 . Calibration Loads Adjusted for Iteration 1 Tare Loads . 31 Table 1 O . Iteration 1 Interim Mat
11、rix 32 Table 11 . Iteration 2 Tare Loads and Changes . 33 Table 12 . Calibration Loads Adjusted for Iteration 2 Tare Loads . 33 Table 13 . Iteration 2 Interim Matrix 35 35 Table 15 . Calibration Loads adjusted for Iteration 3 Tare Loads 36 Table 16 . Iteration 3 Interim Matrix 37 Table 17 . Iteratio
12、n 4 Tare Loads and Changes . 38 Table 18 . Calibration Loads Adjusted for the Final Tare Loads 38 Table 19 . Final Calibration Matrix 40 Table 20 . Contents of the Calibration Matrix File 41 Table 21 . Sample Calibration Matrix File . 42 45 Table 23 . Balance Details for a Calibration Report . 46 Ta
13、ble 24 . Calibration Details for a Calibration Report . 47 Table 25 . Data Reduction Description for a Calibration Report 48 Table 26 . Back-calculated Data and Residuals 51 Table 27 . Calibration Statistical Data . 53 Table 14 . Iteration 3 Tare Loads and Changes Table 22 . General Information for
14、a Calibration Report Figures Figure 1 . Balance Axis System, Forces, and Moments 3 Figure 2 . Matrix Determination Process 17 Figure 3 . Sample Load Calculation 20 Figure 4 . Applied Loading as Function of Database Point Number . 50 Figure 5 . Normalized Calibration Loading in Two-component Load Env
15、elope Format . 50 Figure 6 . Load Envelope Sample for a Three Component Force Balance 50 Figure 7 . Residual Load Error and Applied Loading as Function of Load Point Number 54 Figure 8 . Normalized Residual Load Error and Normalized Applied Loading as Function of Load Point Number 55 Figure 9 . Hist
16、ogram of Normalized Residual Load Error with Theoretical Normal Distribution Superimposed 56 iv AIAA R-091-2003 Foreword Internal balances are the mainstay instrument used in nearly every wind tunnel test to measure the aerodynamic loads on the test article. For the most part, each facility designs,
17、 fabricates, calibrates, and utilizes internal balances in near seclusion. However, with decreasing budgets and customers using multiple facilities, the time had arrived for collaboration on the design, use, calibration, and uncertainty estimation for internal strain-gage balances to begin. The conc
18、ept of forming a working group for internal balances originated from discussions among individuals from the Arnold Engineering Development Center, the National Aeronautics and Space Administration facility at Langley Research Center, and the Boeing Commercial Airplane Group. The discussions also rev
19、ealed that there was considerable skepticism concerning the willingness to share information and the ability to reach consensus among the individuals working in the area of internal balances. However, despite the skepticism, it was decided that the working group concept should go forward with the pu
20、rpose of sharing information and developing recommended practices. The Ground Testing Technical Committee (GTTC) of the American Institute of Aeronautics and Astronautics (AIAA) was asked to sponsor a working group on internal balance technology. Upon approval, the Internal Balance Technology Workin
21、g Group (IBTWG) was formed under the auspices of the GTTC. The objective of the IBTWG was to share information on, and experiences with, all facets of internal balances and to develop recommended practices that would allow the facilities to work together to advance the state of the art. The working
22、groups membership consisted primarily of individuals from organizations that calibrate and use internal balances. One of the early issues that had to be addressed was the working groups membership. Invitations to the first meeting were made to individuals from facilities in the U.S. and Canada. Howe
23、ver, during the time of the first meeting, several European organizations expressed an interest in participating in the working group. After considerable debate, the initial invited members agreed that achieving consensus was going to be a difficult enough task among the current members and that exp
24、anding the membership might impede the groups progress, possibly to the point of being ineffective. The initial members agreed that the current group be limited to North American participation, but would support the development of a European working group if requested. Then, once recommended practic
25、es had been developed in both groups, representatives of each group could meet to develop a mutual set of recommended practices. As of the publication date of this document, a temporary UK working group was formed; however, a European working group had yet to be formed. The following objectives were
26、 set as goals for the working group: 1. 2. 3. 4. 5. 6. 7. Provide a forum for the members to share information on the methodologies and capabilities for internal strain-gage balances. (accomplished and has been very successful) Recommend a calibration matrix format that can be utilized in all of the
27、 testing facilities. (accomplished) Develop general guidelines for selecting a balance type and the extent of calibration necessary to meet the objectives of a particular wind tunnel test. (some discussion but not accomplished) Develop a recommended balance calibration uncertainty methodology that i
28、s in agreement with existing uncertainty standards (AGARD AR-304 and AIAA S-O71 A-1999). (partially addressed) Develop methods of accounting for weight tare adjustments (both calibration and testing) that are accepted by the members. (accomplished for calibration only) Investigate new methodologies
29、for the design, attachment, and calibration of internal balances. (not addressed) Develop and publish a Recommended Practices document for internal strain-gage balance methodologies, including an adjustment methodology for thermal effects on balances. V AIAA R-091-2003 (accomplished with the publica
30、tion of this document, excluding thermal effects. Although thermal effects have a large affect on a balance, they are not included here since the existing methodologies were so diverse and there did not appear to be a time effective solution to the issue.) Note that the objectives do not include the
31、 implementation of any recommended practices, only the development. This is a result of most of the membership not being in positions in their organizations where they can decide such issues. However, all members agreed that they would promote the implementations of the recommended practices at thei
32、r facilities. The working group made excellent progress in three areas: the exchange of information, which includes developing open communications and trust among the members; documentation of the balance technology in use at the member organizations; and the establishment of recommended practices.
33、These efforts will benefit the wind tunnel testing community as a whole, as the recommended practices will improve understanding and communication between facilities and provide the potential to mitigate test costs, and improve the quality of test data. The following officers and members have provid
34、ed dedicated support, contributions, and leadership to the AIAA/GTTC Internal Balance Technology Working Group. Their efforts have resulted in the development of this Recommended Practice. David Cahill Nancy Swinford Allen Arrington Dennis Booth Richard Crooks Robin Galway Andrew Garrell Don Hamilto
35、n Steve Hatten Mark Kammeyer Chris Lockwood Phillip Luan Ray Rhew Stan Richardson Paul Roberts Mat Rueger Lew Scherer Frank Steinle Jim Thain Johannesvan Aken Chair, Sverdrup Technology Inc, AEDC Group Secretary, Lockheed Martin Space Systems Co. Secretary, QSS Group Inc., NASA Glenn Research Center
36、 Allied Aerospace, GASL Division, Force Measurement Systems Allied Aerospace, Flight Systems Division RobGal Aerotest Consulting (Retired IAR/NRC) Veridian Engineering (formerly Calspan) Institute for Aerospace ResearchINRC The Boeing Company The Boeing Company Sverdrup Technology Inc., Ames Group S
37、verdrup Technology Inc., Ames Group NASA Langley Research Center Sverdrup Technology Inc., AEDC Group NASA Langley Research Center The Boeing Company Northrop Grumman Sverdrup Technology Inc., AEDC Group Institute for Aerospace ResearchINRC Aerospace Computing, NASA Ames vi AIAA R-091-2003 Doug Voss
38、 The Boeing Company Jimmy Walker Lockheed Martin LSWT Frank Wright Pat Whittaker The Boeing Company (Deceased) NASA Ames Research Center The AIAA Ground Testing Technical Committee (Mr. Dan Marren, Chairperson) approved the document for publication in January 2001. The AIAA Standards Executive Counc
39、il (Phil Cheney, Chairman) accepted the document for publication in September 2003. The AIAA Standards Procedures provide that all approved Standards, Recommended Practices, and Guides are advisory only. Their use by anyone engaged in industry or trade is entirely voluntary. There is no agreement to
40、 adhere to any AIAA standards publication and no commitment to conform to or be guided by a standards report. In formulating, revising, and approving standards publications, the Committees on Standards will not consider patents which may apply to the subject matter. Prospective users of the publicat
41、ions are responsible for protecting themselves against liability for infringement of patents or copyrights, or both. Ded cat ion The Internal Balance Technology Working Group has dedicated this Recommended Practice in the memory of Mr. Frank L. Wright, formerly of The Boeing Company. Frank was instr
42、umental in the formation of this working group and the sharing of his wind tunnel testing experience, knowledge, and insight through his participation were instrumental in its success. AIAA R-091-2003 1 Introduction 1.1 Scope This document provides a recommended method for calibration of internal st
43、rain-gage balances used in wind tunnel testing. The practices include terminology, axis system definition, balance calibration methods, matrix, and documentation. Use of this document will facilitate the exchange of information among users, suppliers, and other interested parties. 1.2 Purpose Intern
44、al strain-gage balances are used extensively to measure the aerodynamic loads on a test article during a wind tunnel test. There has been little collaboration on internal balances; consequently, several types of balances, calibration methods, calibration matrices, tare adjustments, and uncertainty e
45、valuations have evolved. The purpose of the group was to pool their information and experiences to enhance each others capabilities and to develop recommended practices for the use, calibration, tare adjustment, and uncertainty evaluation of internal balances. The acceptance and universality of a re
46、commended practice is dependent on how well the organizations involved represent the industry. In this instance the Internal Balance Technology Working Group had membership and participation from all of the major wind tunnel facilities and aircraft developers in North America. The fact that these or
47、ganizations were able to agree on the recommended practices contained in this document will provide the weight necessary to instill their adoption, not only in North America but many of the recommended practices will be adopted by organizations around the world. The members of the working group repr
48、esented the following organizations: Arnold Engineering Development Center (AEDC) The Boeing Company Veridian Engineering (formerly Calspan) Institute for Aerospace Research, Canada (IAR) Lockheed Martin Northrop Grumman Allied Aerospace (formerly Micro Craft) NASA Ames Research Center (ARC) NASA Gl
49、enn Research Center (GRC) NASA Langley Research Center (LaRC) This document presents the reader with a clear means of designating balance types and gage nomenclature, a concise methodology (including tare corrections) for balance calibration, the reporting of the balance calibration matrix, and for the reporting of statistical and calibration specific information. An example of the balance calibration data reduction process is available for downloading on the GTTC website. The GTTC website can be accessed via the Technical Committees link on the AIAA website at .
