ASD-STAN PREN 2746-1990 Aerospace Series Glass Fibre Reinforced Plastics Determination of Flexural Properties Three Point Bend Method (Issue P 1)《航空航天系列 玻璃纤维增强塑料 三点弯曲法测定挠性特性 第P1版》.pdf
《ASD-STAN PREN 2746-1990 Aerospace Series Glass Fibre Reinforced Plastics Determination of Flexural Properties Three Point Bend Method (Issue P 1)《航空航天系列 玻璃纤维增强塑料 三点弯曲法测定挠性特性 第P1版》.pdf》由会员分享,可在线阅读,更多相关《ASD-STAN PREN 2746-1990 Aerospace Series Glass Fibre Reinforced Plastics Determination of Flexural Properties Three Point Bend Method (Issue P 1)《航空航天系列 玻璃纤维增强塑料 三点弯曲法测定挠性特性 第P1版》.pdf(9页珍藏版)》请在麦多课文档分享上搜索。
1、AECMA PREN2746 40 W 101231L O004082 4 U, Edition approved for publication Comments should be sent within six months after the date of publication decision 88, Bd. Malesherbes 1990-08-24 A.E.C.M.A. 75008 PARIS - FRANCE A. E, C. M .A. STAN DARD NORME A.E.C.M.A. A.E.C.M.A. NORM C7 Chairman Mr. BEZAUD p
2、rEN 2746 Issue P 1 August 1990 DIT PAR LASSOCIATION EUROPENNE DES CONSTRUCTEURS DE MATRIEL AROSPATIAL 88, boulevard Malesherbes, 75008 PARIS -TL. 45-63-82-85 UDC : Key words : ENGLISH VERSION Aerospace series Glass fibre.reinforced plastics Determination of flexural properties Three point bend metho
3、d Srie arospatiale Luft- und Raumfahrt Matires plastiques renforces au verre textile Dtermination des caractristiques de flexion Glasfaserverstrkte Kunststoffe Biegeprf ung Mthode des trois pannes Dreipunkt-Verfahren This .Aerospace Series pre-standard has been drawn up under the responsibility of A
4、ECMA (Association Europenne des Constructeurs de Matriel Arospatial). It is published on green paper for the needs of AECMA-Members. It has been technicallyapprovedby the experts of the concerned Commission following comment by the Member countries. Subsequent to the publication of this pre-standard
5、, the technical content shalinot be changed to an extent that interchangeability is affected, physically or functionally, without re-identification of the standard. After examination and signature of the AECMA Standard Checking Centre (NPS) and formal agreement of the Official Services of the Member
6、 countries it will be submitted as a draft European Standard to CEN (European Committee for Standardization) for final vote. - AECMA PREN2746 90 LOL23LL 0004083 b W prEN 2746 Page 2 Contents Sccpe and field of application References Def inj.tions Apparatus Test pieces Procedure Calculation and expre
7、ssion of the results Test report AECMA PREN274b 90 IOL23LL OOOLiOB4 B O * O O 1 S prEN 2746 Page 3 3pe and field of application This standard describes a method for the determination of the fiexural properties of glass fibre reinforced plastic materials in the form of rectangular bars, of standardis
8、ed dimensions or not, moulded directly or cut frorr. panels or other mouldings. It only applies to single bars, supported without constraint, loaded in the middle of the span (three point bending methocl) 1). The following properties may be determined by using the method described, 1.1 Flexural stre
9、ss and flexure at failure of materials which breok before cr on reaching normal flexure. 1.2 Flexural stress for normal flexure of materials which do not break before or at normal flexure, 1.3 Flexural stress for the ultimate load, in the case of materials which reach ultimate load before or at norm
10、al flexure. 1.4 Flexural stress at failure or for the ultimate load in cases where the normal flexure is exceeded and if this is required by the material . Note : If the flexure is greater than the normal flexure, it may not be possibie to make a direct comparison of flexural stress results for diff
11、erent test pieces. 1.5 Where applicable, the apparent elastic modulus in flexure (elastic modxlus determined by flexural test). Note : The elastic modulus in flexure should only be considered as an approximate value of YOUNGS modulus of elasticity. 2 Referen-ces EN 2374 Aerospace series - Glass fibr
12、e reinforced mouldings and sandwich composites - Production of test panels ER 2489 Aerospace series - Fibre reinforced plastics - Determination of the action of liquid chemicals 2) EN 2743 Aerospace series -a Beinforced plastics - Standard atmospheres for conditioning and testing 3) EN 2823 Ae.rospa
13、cc series - Fibre reinforced plastics - Test method for the determination of the effect of exposure to humid atmospheres on physical and mechanical characteristics 3) 1) A method in wh5ch the load is applied st 2 points (the 4 point bend method) allnws piire flexural stresses to be produced in the c
14、entral prxt of the n est piece. The. compression stresses caused by the points are Euch lower than that produced perpendicular to the central point in the three point bend method. The present European standard does not deal with the four point bend method. 2) Published as AECMA pre-standard at the d
15、ate of publication of the present standard. 3) III preparation at the date cf publication of the present standard. AECIA PREN274b 90 M 1012311 0004085 T M prEN 2746 Page 4 3 Definitions The following definitions are applicable within the framework of the present standard : 3.1 Flexure Distatice trav
16、elled during bending, from its initial position, by the lower or upper surface of the test piece in the middle of its span. 3.2 Flexural stress at a given moment during the test Ultimate stress on the external fibre of the material. in the section of the test piece located in the middle of the span.
17、 It is calculated in accordance with the general formula given in clause 7.1. 3.3 Flexural stress at specified flexure Flexural stress for a flexure equal to 1,5 times the thickness cf the test piece. 3.4 Flexural stress at ultimate load Flexural stress at the moment when the load reaches the ultima
18、te value. 3.5 Flexural stress at failure Flexural stress at the instant of failure. 3.6 Modulus of elasticity in flexure The modulus of elasticity in flexure is defined from the tangent of the initial part of the oad/deflection curve and calculated with the formula given in clause 7.2. 4 Apparatus T
19、he. testing machine, suitably constructed and calibrated, allowing relative displacement of the loading nose wi.th respect to the supports at a constant rate V, and indicating the loads with an error not exceeding $. 1 Z and the flexures with an error not exceeding + - 2 2. The supports and the load
20、ing nose shall be at least as wide as the test piece and shall be parallel to one another. The radius, r15 of the loading nose and the radius, r as follows : of the supports shall be 2 r = (5 f 0,l) mm, r1 = (2 5 0,2) mm. 2 It shall be possible to adjust the span, i., between the supports (see figur
21、e 1) AECMA PREN274b 90 a LOL23LL 0004086 L =, _- prEN 2746 Page 5 0 5 Test pieces If it- is impossible to obtain test pieces from the finished product, prepare laminates or panels according to EN 2374 or by a suitable method by prior agreement between the parties concerned and as near as possible to
22、 the method of manufacture of the product under consideration or envisaged. The test pieces shall be taken from these laminates or panels, 5.1 Dimensions of test pieces (3 + 0,2) mm - Thickness “h“ : - (15 5 0,5) mm - Width - Length “1“ : (20.h) + - im If test pieces of thickness greater than 3 mm a
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