1、 Reference numberISO 14828:2003(E)ISO 2003INTERNATIONAL STANDARD ISO14828First edition2003-12-01Glass-reinforced thermosetting plastics (GRP) pipes Determination of the long-term specific ring relaxation stiffness under wet conditions and calculation of the wet relaxation factor Tubes en plastiques
2、thermodurcissables renforcs de verre (PRV) Dtermination de la rigidit annulaire spcifique long terme en relaxation, en conditions mouilles, et calcul du facteur de relaxation au mouill Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo rep
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7、on in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2003 All rights reserved
8、Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ISO 14828:2003(E) ISO 2003 All rights reserved iiiContents Page Foreword iv 1 Scope 1 2 Normative references . 1 3 Terms a
9、nd definitions. 1 4 Principle . 4 5 Apparatus. 4 5.1 Compressive loading machine 4 5.2 Force application surfaces. 4 5.3 Water container . 5 5.4 Measuring devices 5 6 Test piece. 6 7 Number of test pieces. 6 8 Determination of the dimensions of the test pieces . 7 8.1 Length 7 8.2 Wall thickness . 7
10、 8.3 Mean diameter . 7 9 Conditioning 7 10 Procedure. 7 11 Calculation. 8 11.1 Extrapolation of the loading data 8 11.2 Calculation of the long-term specific ring relaxation stiffness under wet conditions for position 1 . 8 11.3 Calculation of the wet relaxation factor 8 12 Test report 9 Annex A (in
11、formative) Equal increments of lg(time in h) . 10 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ISO 14828:2003(E) iv ISO 2003 All rights reservedForeword ISO (the Inter
12、national Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has
13、been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical st
14、andardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies
15、for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or
16、all such patent rights. ISO 14828 was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for the transport of fluids, Subcommittee SC 6, Reinforced plastics pipes and fittings for all applications. Copyright International Organization for Standardization Provided by IHS
17、under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-INTERNATIONAL STANDARD ISO 14828:2003(E) ISO 2003 All rights reserved 1Glass-reinforced thermosetting plastics (GRP) pipes Determination of the long-term specific ring relaxation stiffness under
18、wet conditions and calculation of the wet relaxation factor 1 Scope This International Standard specifies a method for determining both the long-term specific ring relaxation stiffness and the wet relaxation factor for glass-reinforced thermosetting plastics (GRP) pipes. 2 Normative references The f
19、ollowing referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 7685:1998, Plastics piping systems Glass-reinforce
20、d thermosetting plastics (GRP) pipes Determination of initial specific ring stiffness ISO 10928:1997, Plastics piping systems Glass-reinforced thermosetting plastics (GRP) pipes and fittings Methods for regression analysis and their use 3 Terms and definitions For the purposes of this International
21、Standard the following definitions apply: 3.1 vertical compressive force F vertical force, expressed in newtons, applied to a horizontal pipe to cause a vertical deflection 3.2 specific ring stiffness S physical characteristic of a pipe, expressed in newtons per square metre, that is a measure of th
22、e resistance to ring deflection per metre length under external load and is defined by Equation (1): 3mE ISd= (1) where E is the apparent modulus of elasticity, in newtons per square metre, determined by testing in accordance with ISO 7685; I is the second moment of area in the longitudinal directio
23、n per metre length, in metres to the fourth power per metre (m4/m), i.e. 312eI = (2) Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ISO 14828:2003(E) 2 ISO 2003 All righ
24、ts reservede being the wall thickness of the pipe, in metres; dmis the mean diameter of the pipe, in metres (see 3.3). 3.3 mean diameter dmdiameter, expressed in metres, of the circle corresponding with the middle of the pipe wall cross-section and given by either of the following equations: midde=+
25、 (3) medde= (4) where diis the internal diameter, in metres; deis the external diameter, in metres; e is the wall thickness of the pipe, in metres. 3.4 initial specific ring stiffness S0value of S, expressed in newtons per square metre, determined by testing in accordance with ISO 7685 3.5 long-term
26、 specific ring relaxation stiffness at position 1 Sx, 1, relax, wetvalue of S, expressed in newtons per square metre, at a reference position, position 1 (see 10.2), at x years, obtained by extrapolation of long-term force measurements at a constant deflection under wet conditions (see 3.2 and 10.2)
27、 3.6 calculated long-term specific ring relaxation stiffness under wet conditions Sx, relax, wetcalculated value of S, expressed in newtons per square metre, at x years obtained using Equation (5): , relax, wet 0 , relax, wetxxSS= (5) where x is the elapsed time, in years, specified in the referring
28、 standard; x, relax, wetis the wet relaxation factor (see 3.7); S0is the initial specific ring stiffness, in newtons per square metre. 3.7 wet relaxation factor x, relax, wetratio of the long-term specific ring relaxation stiffness to the initial specific ring stiffness, both at a reference position
29、, position 1 (see 10.2), and given by Equation (6): ,1, relax, wet, relax, wet0, 1xxSS = (6) Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ISO 14828:2003(E) ISO 2003 Al
30、l rights reserved 3where S0, 1is the initial specific ring stiffness at position 1, in newtons per square metre, determined in accordance with ISO 7685; Sx, 1, relax, wetis the long-term specific ring relaxation stiffness at position 1, in newtons per square metre 3.8 vertical deflection y vertical
31、change in diameter of a pipe in a horizontal position, expressed in metres, in response to a vertical compressive force (see 3.1) 3.9 long-term applied force Fx, 1, wetvalue of the force F, expressed in newtons, at the reference position, position 1 (see 10.2), at x years obtained by extrapolation o
32、f long-term applied-force measurements at a constant deflection under wet conditions (see 3.1 and 10.2) 3.10 deflection coefficient f dimensionless factor which takes into account general second-order theory as applied to deflection and is given by Equation (7): ()51m1860 2 500 / 10fyd=+ (7) where y
33、1is the vertical deflection at position 1, in metres; dmis the mean diameter (see 3.3) of the pipe, in metres. 3.11 calculated strain calc, 1strain on the inner surface at the crown and invert of a pipe at the reference position, position 1, given in percent by Equation (8): 1mmcalc,121m4,28 10012ye
34、ddyd=+(8) where y1is the vertical deflection at position 1, in metres; dmis the mean diameter of the pipe (see 3.3), in metres; e is the wall thickness of the pipe, in metres. Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction
35、 or networking permitted without license from IHS-,-,-ISO 14828:2003(E) 4 ISO 2003 All rights reserved4 Principle A cut length of pipe supported horizontally is loaded throughout its length to compress it diametrically to a prescribed level of strain calculated using Equation 8. The force applicatio
36、n surfaces are either bearing plates or beam bars. The pipe is immersed in water at a given temperature for a period of time during which the vertical deflection remains constant and the force is measured at intervals. The long-term force is estimated by extrapolation. From this force and the deflec
37、tion, the long-term specific ring relaxation stiffness under wet conditions is calculated. The wet relaxation factor is then determined from the long-term specific ring relaxation stiffness and the initial specific ring stiffness of the same test piece. The declared wet relaxation factor is the aver
38、age of the results from two test pieces. NOTE It is assumed that values for the following test parameters will be set by the standard making reference to this International Standard: a) the method for measuring the initial specific ring stiffness, i.e. method A or B of ISO 7685:1998 (see 3.4); b) th
39、e time to which the values are to be extrapolated (see 3.6 and 11.1); c) the test temperature (see 5.3 and 10.1); d) the length of the test piece (see Clause 6); e) if applicable, the conditioning parameters, i.e. temperature, humidity and duration (see Clause 9); f) the time limits for maintaining
40、the test piece under load (see 10.6); g) the level of strain at which the test is to be conducted. 5 Apparatus 5.1 Compressive loading machine The machine shall comprise a system capable of applying a force, without shock, through two parallel force application surfaces conforming to 5.2 so that a h
41、orizontally orientated test piece of pipe conforming to Clause 6 and immersed in water can be compressed vertically and maintained at a constant deflection for the duration of the test in accordance with 10.6. The machine shall include equipment, such as a load cell (see 5.4), for measuring the forc
42、e applied to within 1 % of the maximum measured force for the duration of the test. Ensure that the applied force takes into account buoyancy effects and is not affected by friction. 5.2 Force application surfaces The method allows the use of either bearing plates or beam bars for loading the test p
43、iece, subject to reporting the choice used. The same loading arrangement (plates, bars, or plate and bar) shall be used for the determination of both initial and long-term stiffness. 5.2.1 General arrangement The surfaces shall be provided by a pair of plates, conforming to 5.2.2, or a pair of beam
44、bars, conforming to 5.2.3, or a combination of one such plate and one such bar, with their major axes perpendicular to and centred on the direction of application of force F exerted by the compressive loading machine, as shown in Figure 1. The surfaces to be in contact with the test piece shall be f
45、lat, smooth, clean and parallel. Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ISO 14828:2003(E) ISO 2003 All rights reserved 55.2.2 Plates The plate(s) shall have a wi
46、dth of at least 100 mm and a length at least equal to the length of the test piece (see Clause 6). They shall be sufficiently stiff so that they do not visibly bend or otherwise deform during the test. 5.2.3 Beam bars Each beam bar shall be sufficiently stiff that it does not visibly bend or otherwi
47、se deform during the test. Each beam bar shall have a length at least equal to the length of the test piece (see Clause 6) and a flat face (see Figure 1) without sharp edges. The width of the flat face shall be 15 mm to 55 mm. The beam bars shall be so constructed and supported that no other surface
48、 of the beam bar structure comes into contact with the test piece during the test. 5.3 Water container Required is a container large enough to accommodate submerged test pieces conforming to Clause 6 whilst they are subject to the compressive force in accordance with 10.6 and containing tap water ha
49、ving a pH of 7 2 and kept at the specified temperature (see 10.1). The water level shall be maintained sufficiently constant to avoid any significant effect on the value of the vertical force applied to the test piece. 5.4 Measuring devices Required are devices capable of determining: a) the necessary dimensions (length, diameters, wall thicknes
