1、Designation: F 2433 05An American National StandardStandard Test Method forDetermining Thermoplastic Pipe Wall Stiffness1This standard is issued under the fixed designation F 2433; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the load-deflection behavior of thermoplastic pipe wall sectio
3、ns underparallel plate loading conditions.NOTE 1These are not full pipe section tests, but pipe wall segmenttests. The results of these tests will be different from pipe stiffness tests perTest Method D 2412, although they may be proportional. This testprovides quite different information, including
4、 , stress relaxation underconstant strain, and comparisons of the function and stiffness of differentpipe wall designs or materials.1.2 This test method covers a loading test for determiningthe wall stiffness of a thermoplastic-pipe wall under a com-bined load of bending and compression. Changes in
5、pipe wallprofile geometry under load may also be determined.1.3 This test method covers thermoplastic pipe.1.4 The characteristics determined by this test method arewall stiffness and changes in profile wall dimensions at specificdeformations.1.5 The characteristics determined by this test method ar
6、ewall stiffness, profile wall efficiency, and for some wallelements stability at specific Strain levels.1.6 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.7 The text of this specification references notes andfootnotes that p
7、rovide explanatory material. These notes andfootnotes (excluding those in tables and figures) shall not beconsidered as requirements of the specification.1.8 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of t
8、his standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 618 Practice for Conditioning Plastics for TestingD 695 Test Method for Compressive Properties of RigidPlasticsD 883
9、 Terminology Relating to PlasticsD 1600 Terminology for Abbreviated Terms Relating toPlasticsD 2122 Test Method for Determining Dimensions of Ther-moplastic Pipe and FittingsD 2412 Test Method for Determination of External LoadingCharacteristics of Plastic Pipe by Parallel-Plate LoadingF 412 Termino
10、logy Relating to Plastic Piping Systems2.2 AASHTO Standards:M 252 Standard Specification for Corrugated PolyethyleneDrainage Pipe3M 294 Standard Specification for Corrugated PolyethylenePipe, 300- to 1500-mm Diameter33. Terminology3.1 DefinitionsDefinitions are in accordance with Termi-nology F 412,
11、 and abbreviations are in accordance with Ter-minology D 1600, unless otherwise specified.3.2 Definitions of Terms Specific to This Standard:3.2.1 chord shortening, nthe ratio of the reduction in pipesection chord shortening to the initial chord length expressed asa percentage.3.2.2 Dy, nmeasured ch
12、ange in chord length (in thedirection of load application) expressed in millimeters (inches).3.2.2.1 compressive deformation, nthe measured changeof the inside diameter in the direction of load applicationexpressed in millimeters (or inches).1This test method is under the jurisdiction of ASTM Commit
13、tee F17 on PlasticPiping Systems and is the direct responsibility of Subcommittee F17.40 on TestMethods.Current edition approved June 1, 2005. Published June 2005.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book
14、 of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Association of State Highway and TransportationOfficials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001.1Copyright ASTM International, 100 Barr Harbor Dri
15、ve, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.3 load (F), nthe force applied to the wall section toproduce or maintain a given percent chord length shortening atany given unit of time; expressed as Newtons per meter(pounds-force per linear inch).3.2.4 mean radius (r), nthe mid
16、-wall radius determinedby subtracting the average wall thickness from the averageoutside diameter and dividing the difference by two; expressedin millimeters (or inches).3.2.5 time-independent pipe stiffness K(0), nthe valueobtained by dividing the force per unit length on the curvedbeam specimen by
17、 the resulting deflection in the same units atthe % deflection prescribed and extrapolating the linear portionof the curve of stiffness versus % deflection to the moment ofapplication of load.3.2.6 time-dependent residual curved beam stiffness K(t)and residual pipe stiffness K(t), nthe value obtaine
18、d bydividing the force per unit length on the curved beam specimenby the constant target deflection in the same units, at any timet, t 0.3.2.7 modulus of relaxation, nthe residual pipe stiffnessversus log(time).3.2.8 residual pipe stiffness K(50y), nthe value obtainedby extrapolating values of resid
19、ual pipe stiffness versus time to50 years.3.2.9 compliance C(t), nthe inverse of stiffness K(t).3.2.10 liner cracking or crazing, nthe occurrence of abreak or network of fine breaks in the liner visible to theunaided eye.3.2.11 wall cracking, nthe occurrence of a break in thepipe wall visible to the
20、 unaided eye.3.2.12 wall delamination, nthe occurrence of any separa-tion in the components of the pipe wall visible to the unaidedeye.3.2.13 rupture, na crack or break extending entirely orpartly through the pipe wall.4. Summary of Test Method4.1 The test is conducted by applying a controlled, near
21、lyinstantaneous, load to the longitudinally cut edges of curvedbeam sections cut from short lengths of pipe until a prescribedshortening of the chord connecting the longitudinal edges isachieved and held constant for prescribed intervals. Load anddeformation data establish the time-independent measu
22、re ofcurved beam wall stiffness at the instant of load application, themeasure of efficiency of the profile wall geometry, stability ofthe profile wall, a modulus of relaxation and long-termestimates of residual pipe wall stiffness.4.2 Alength of a 10 to 120 arc segment of a pipe wall, fromone diame
23、ter length to one meter long is loaded across its chordlength between two freely rotating end plates at a controlledrate of approach to one another. Load-deflection data of thewall section in combined bending and compression are ob-tained. Change in pipe wall thickness at the center of thesection (s
24、pringline) is determined. If cracking, crazing, delami-nation, rupture, or buckling occurs, the corresponding load,deflection, and/or time are recorded.NOTE 2If this test method is incorporated in a product standard itwould be necessary to define the arc length to be tested. There are,however, many
25、reasons various arc lengths might be tested, especially asa research or product development tool. Large arc lengths are primarily inbending, while short arc lengths are primarily in compression.5. Significance and Use5.1 The performance under bending and compression loadof a thermoplastic plastic pi
26、pe wall design obtained by thismethod can be used for the following:5.1.1 To determine the stiffness of the pipe wall section.This is a function of the pipe dimensions, the wall design, thearc length tested, and the physical properties of the material ofwhich the pipe is made.5.1.2 To compare the ch
27、aracteristics of various thermoplas-tic pipe wall designs.5.1.3 To compare the characteristics of various plastics inpipe form.5.1.4 To study the interrelations of dimensions, materials,and deformation properties of thermoplastic pipe designs.5.1.5 To measure the deformation and load-resistance at a
28、nyof several significant events which may occur during the test.5.1.6 To provide a reasonable quality control/quality assur-ance test for very large diameter plastic pipes.5.2 The time-dependent pipe wall stiffness of a thermoplas-tic pipe obtained by this test method may used for thefollowing:5.2.1
29、 To predict the residual stiffness of the pipe wall inbending and compression at all times after initial loading.5.2.2 For purposes of design, to determine a modulus ofrelaxation under sustained loads.5.2.3 To quantify the influence of material formulations ofthermoplastics on the modulus of relaxat
30、ion.5.2.4 To study the influence of geometric patterns of wallprofiles on the modulus of relaxation.5.3 The time-independent reduction of wall thickness atspringline may be used for the following:5.3.1 For pipe wall stiffness, to quantify the efficiency of allwall profiles of any material compositio
31、n and a given geometrywith that of a solid uniform thickness wall.6. Apparatus6.1 Testing MachineA properly calibrated compressiontesting machine of the constant-rate-of-crosshead movementtype meeting the requirements of Test Method D 695 shall beused to make the tests. The rate of head approach sha
32、ll be 63.56 2.5 mm (2.5 6 0.1 in.)/s. The machines must be capable ofholding a required percent chord shorting for an extendedperiod of time.6.2 Loading GripsThe load shall be applied to the speci-men through two parallel-axis grips. These assemblies shall beflat, smooth, and clean. Specimen contact
33、 surfaces of platenshall be coated with a PTFE spray lubricant. The thickness ofthe platens shall be sufficient so that no bending or deformationoccurs during the test, but it shall not be less than 12 mm (0.5in.). The nominal length of each grip shall equal or exceed thespecimen length but shall no
34、t be less than 1040 mm (41 in.).Upper and lower grips shall be free to rotate about an axis inthe plane of the applied and reacting line loads. Recommendedarrangement of loading frame, upper and lower grips with testspecimen are shown in Fig. 1.F24330526.3 Deformation IndicatorThe change in total wa
35、ll (majorwall for profile wall pipe) thickness at springline, shall bemeasured with a suitable instrument meeting the requirementsof 4.1.2 of Test Method D 695, except that the instrument shallbe accurate to the nearest 0.025 mm (0.001 in.). The instrumentshall not affect in any way the load-deflect
36、ion measurements.6.4 Load SensorThe change of load with time during theperiods of displacement (loading) and during the period ofconstant displacement shall be digitally recorded with a preci-sion of no less than 4 significant figures and at time intervals asnoted in 9.3. The sensing element shall h
37、ave a precision of62 % of maximum recorded value.6.5 Temperature RecorderAmbient temperature shall becontinuously recorded using a sensor capable of recording to1C (1.8F).6.6 Reaction FrameThe reaction frame shall be suffi-ciently rigid such that the movement of the stationery platenshall not exceed
38、 0.05 % of the displacement of the movingplaten.7. Test Specimens7.1 Test specimens shall be cut from the pipe wall, with thecuts through the wall radial and parallel through the samplelength. Test specimens may be the required arc length indegrees 61 arc sections of the wall, as agreeable to theman
39、ufacturer and the purchaser, but not less than 10 degreesnor greater than 120 degrees. Test specimens should be aminimum of 600 mm (24 in.) long, and may be as much as 900mm (36 in.), and for corrugated or profile pipe should besquarely cut in the corrugation or profile valley.NOTE 3Standard arc len
40、gths for specimens should be 120, 90, and30, though other arc lengths may be used within the range of 120 to 10,as determined by the needs of the owner, researcher, or testing laboratory.8. Conditioning8.1 Condition the pipe wall section for at least 24 h in air ata temperature of 23 6 2C (73.4 6 3.
41、6F), and 50 6 5%relative humidity and conduct the test in a room maintained atthe same temperature.8.2 When a referee test is required, condition specimens forat least 40 h at 23 6 2C (73.4 6 3.6F), and 50 6 5 % relativehumidity per Practice D 618 Procedure A and conduct the testunder the same condi
42、tions.9. Procedure9.1 Before placing each test specimen in the test apparatusmake the following measurements:9.1.1 Measure, to the nearest 1 mm (0.04 in.), the longitu-dinal length with equally spaced parallel measurements at midand quarter points of the arc of the curved beam. Determine thelongitud
43、inal length by averaging the three measurements.9.1.2 For specimens prepared from AASHTO M 252M andAASHTO M 294M Type C pipes, at each of three pointsapproximately located on a mid-longitudinal line of the corru-gated wall, one point located at mid-length and two pointslocated at one-quarter and thr
44、ee-quarter lengths, determine theFIG. 1 Recommended Arrangement of Loading Frame, Upper expressed as Newtons permeter (pounds-force per linear inch), andDy = measured change in chord length (in the direction ofload application) expressed in millimeters (inches).FIG. 2 Photographs of Specimen in Load
45、 Frame (continued)F2433055NOTE 4Immediately after the moment of initiation of continuousapplication of load, the load of record incorporates the influences of thecontinuing application of load and the relaxation of previously appliedload. The net load at any time t, t 0, is characterized as the resi
46、dual load;the quantity, load per unit length divided by the associated displacementis characterized as the residual stiffness. These definitions also applyduring the extended period when displacements are held constant withoutfurther application of load.10.1.2 For the interval beginning at the insta
47、nt of loadapplication and ending when the deflection of the curved beamreaches 10 % shortening of the chord, plot, on cartesiancoordinates, curved beam stiffness, K(t) versus % deflection.10.1.3 Through the points between 2 % deflection and 8 %deflection fit a least squares estimate of a straight li
48、ne.10.1.4 Calculate the intercept, K(0) at time t =0.NOTE 5Stiffness versus deflection is typically a smooth curve. Theeffective zero point of zero time is established by deleting the stiffness-time record prior to, and immediately after, the application of loadrecorded and extrapolating the initial
49、 straight line portion of the curvebackwards to zero load.10.2 Estimate the residual pipe wall stiffness, K(t),of300mm (12 in.) diameter solid wall pipes after 50 years, K(50y),and after 100 years, K(100y).10.2.1 Calculate and plot the residual stiffness, K(t) versus1/log (t), t = time in seconds, for all points beginning at thetime of 10 % displacement of the curved beam extendingthrough a period of no less than six (6) weeks.10.2.2 Using the method of least squares linear regressioncalculate the parameters of the best line fitting the data point
