1、 STD-AECMA PREN 27LB-ENGL 3997 m 30L233L 0032048 985 m Edition approved for publication AECMA STANDARD NORME AECMA AECMA NORM Comments should be sent within six months after the date of publication to C5 Chairman prEN 2718 Edition P 1 February 1997 PUBLISHED BY THE EUROPEAN ASSOCIATION OF AEROSPACE
2、INDUSTRIES (AECMA) Guiledelle 94 - 8-1200 BRUXELLES - Tel. (32) 2 775 81 10 - Fax. (32) 2 775 81 11 ICs : Descriptors : ENGLISH VERSION Aerospace series Aluminium and aluminium alloys Test method Measurement of circumferential residual stress in circular tubes with a ratio Dla 2 10 Srie arospatiale
3、Aluminium et alliages daluminium Mthode dessai Mesure de la contrainte rsiduelle circonfrentielle dans les tubes avec ratio Da 2 10 Luft- und Raumfahrt Aluminium und Aluminiumlegierungen Prf verfahren Bestimmung der Umfangrestspannung in runden Rohren mit einem AuBendurchmesser Da 2 10 This “Aerospa
4、ce Series“ Prestandard has been drawn up under the responsibility of AECMA (The European Association of Aerospace Industries). It is published on green paper for the needs of AECMA-Members. It has been technically approved by the experts of the concerned Technical Committee following comment by the
5、Member countries. Subsequent to the publication of this Prestandard, the technical content shall not be changed to an extent that interchangeability is affected, ph ysicaily or functionally, without re-identification of the standard. After examination and signature of the AECMA Standard Checking Cen
6、tre (NPSI and formal agreement of the Official Services of the Member countries it will be submitted as a draft European Standard to CEN (European Committee for Standardization) for formal vote. 1997-02-28 AECMA Gulledelle 94 B-1200 BRUXELLES I Mr Odorico l I I I aecma 1997 Copyright Association Eur
7、opeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-STD-AECMA PREN 2718-ENGL 1777 M LOI12311 00120q7 811 Page 2 prEN 27 18: 1997 Contents O Introduction 1 Scope 2 Normative referen
8、ces 3 Definitions 4 Health and safety 5 Principle 6 Testing requirements 7 Inspection and test report Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-P
9、age 3 prEN 271 8: 1997 O Introduction This standard is part of the series of EN metallic material standards for aerospace applications. The general organization of this series is described in EN 4258. 1 Scope This standard defines the methods for the measurement of circumferential residual stress in
10、 circular tubes with a ratio Ola 2 10 in aluminium and aluminium alloys, for aerospace applications. Two testing procedures are described. Unless otherwise agreed with the purchaser, the procedure used shall be at the discretion of the manufacturer. 2 Normative references This European Standard inco
11、rporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this Eur
12、opean Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 4x8 Aerospace series - Metallic materials - General organization of standardization - Links between types of EN standards and their use 1) EN 425
13、9 Aerospace series - Metallic materials - Definition of general terms 2) 3 Definitions For the purposes of this standard the following definitions apply : Definitions of general terms, see EN 4259. 4 Health and safety Resources, test pieces, test samples, test materials, test equipment and test proc
14、edures shall comply with the current health and safety regulations/laws of the countries where the test is to be carried out. Where materials and/or reagents which may be hazardous to health are specified, appropriate precautions in conformity with local regulations and/or laws shall be taken. 5 Pri
15、nciple The method is based on cutting in a longitudinal direction a sample of tube, and measuring the gap between the cut surfaces. 1 ) Published as AECMA Prestandard at the date of publication of this standard 2) In preparation at the date of publication of this standard Copyright Association Europ
16、eene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Page 4 prEN 271 8: 1997 6 Testing requirements 6.1 Resources - cutting equipment ; - measuring equipment of sufficient accuracy fo
17、r the dimensions concerned. 6.2 Test samples/test pieces Three adjacent test specimens 25 mm long cut from the samples of the tube. 6.3 Calibration All measuring equipment shall be calibrated. 6.4 Testing procedure 6.4.1 Procedure I Mark two longitudinal parallel reference lines or at least two pair
18、s of points at a suitable distance apart (approximately 3 mm) on each test specimen as illustrated in Figure 1. Measure this distance d, accurately. Measure the outer tube diameter and wall thickness of each test specimen. Cut each test specimen along a line located centrally between the two referen
19、ce lines of points. The method of cutting shall be at the discretion of the manufacturer, but adequate measures shall be taken to prevent heating of the specimens and to avoid removal of reference lines or points. After cutting, measure new distance d2 between the two lines or points. NOTE : Movemen
20、t may be positive or negative. If the specimen exhibits negative movement .e. the gap closes, either recut along the same line until the cut edges no longer touch or test another sample in the same manner, but with a greater distance between the reference lines. Reference line or points Figure 1 The
21、 distance d, (before cutting) and d2 (after cutting) shall be measured to an accuracy of at least 0,l mm. Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,
22、-,-Page 5 prEN 271 8: 1997 6.4.2 Procedure 2 Mark a longitudinal reference line on each test specimen as illustrated in figure 2. Measure the outer tube diameter at 90 to the reference line and wall thickness of each test specimen. Cut each test specimen along the reference line. The method of cutti
23、ng shall be at the discretion of the manufacturer, but adequate measures shall be taken to prevent heating of the specimens. After cutting, measure the new diameter DI of each test specimen, taking care to avoid deforming the specimen. NOTE : Movement may be positive or negative. If the specimen exh
24、ibits negative movement .e. the gap closes, recut along the same line until the cut edges no longer touch. r Reference line Figure 2 6.5 Expression of results 6.5.1 Procedure 1 The relative displacement of the reference lines or points (positive or negative), is used to determine the level of circum
25、ferential residual stress which exists in the tube as follows : EaA (1 - v2) (D -a) TC ( -a) + A o= Where : o is the circumferential stress in megapascals ; E is the Youngs Modulus in megapascals ; a is the tube wall thickness in millimetres ; A is the relative displacement of two reference lines (d
26、2 - dl) in millimetres ; v is the Poissons ratio ; D is the tube outer diameter as measured on test specimen in millimetres. Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without
27、 license from IHS-,-,-STD-AECMA PREN 27LB-ENGL 1777 10L23LL 0032053 242 W Page 6 prEN 271 8: 1997 6.5.2 Procedure 2 The change in diameter of the tube (positive or negative), is used to determine the level of circumferential residual stress which exists in the tube as follows : Ea6 (1 - v2) (D - 3)
28、(D -a) + 61 o= Where : (3 is the circumferential stress in megapascals ; E is the Youngs Modulus in megapascals ; a is the tube wall thickness in millimetres ; 6 is the change of diameter Dl - DI in millimetres ; v is the Poissons ratio ; D is the tube outer diameter as measured on test specimen in
29、millimetres 6.6 Acceptance criteria The mean of the three measurements of circumferential residual stress shall not exceed the level permitted by the material standard. 7 Inspection and test report An inspection and test report shall be prepared in accordance with the requirements of EN 2078 and sha
30、ll include at least the following information : - reference to the test method standard ; - any other information relevant to the test method(s), (e.g. test condition, test equipment, test procedure .I ; - identification and traceability of the semi-finished product to be tested in accordance with t
31、he technical specification ; - identification and traceability of test pieces taken from test samples (e.g. number, preparation, method, conditioning) ; NOTE : In certain cases, the test piece may be the test sample ; - expression of results (e.g. individual values or mean values, units . ) ; - date
32、 of test ; - traceability to individual performing the test work ; - any incident which may have affected the results ; - any deviation from the test method standard. Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
