1、Designation: D 6109 05Standard Test Methods forFlexural Properties of Unreinforced and Reinforced PlasticLumber and Related Products1This standard is issued under the fixed designation D 6109; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、revision, the 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. Scope*1.1 These test methods are suitable for determining theflexural properties for any solid or hollow
3、 manufactured plasticlumber product of square, rectangular, round, or other geomet-ric cross section that shows viscoelastic behavior. The testspecimens are whole “as manufactured” pieces without anyaltering or machining of surfaces beyond cutting to length. Assuch, this is a test method for evaluat
4、ing the properties ofplastic lumber as a product and not a material property testmethod. Flexural strength cannot be determined for thoseproducts that do not break or that do not fail in the extremeouter fiber.1.2 Test Method Adesigned principally for products in theflat or “plank” position.1.3 Test
5、 Method Bdesigned principally for those productsin the edgewise or “joist” position.1.4 Plastic lumber currently is produced using several dif-ferent plastic manufacturing processes. These processes utilizea number of diverse plastic resin material systems that includefillers, fiber reinforcements,
6、and other chemical additives. Thetest methods are applicable to plastic lumber products wherethe plastic resin is the continuous phase, regardless of itsmanufacturing process, type or weight percentage of plasticresin utilized, type or weight percentage of fillers utilized, typeor weight percentage
7、of reinforcements utilized, and type orweight percentage of other chemical additives.1.4.1 Alternative to a single resin material system, diverseand multiple combinations of both virgin and recycled thermo-plastic material systems are permitted in the manufacture ofplastic lumber products.1.4.2 Dive
8、rse types and combinations of inorganic andorganic filler systems are permitted in the manufacturing ofplastic lumber products. Inorganic fillers include such materi-als as talc, mica, silica, wollastonite, calcium carbonate, and soforth. Organic fillers include lignocellulosic materials made orderi
9、ved from wood, wood flour, flax shive, rice hulls, wheatstraw, and combinations thereof.1.4.3 Fiber reinforcements used in plastic lumber includemanufactured materials such as fiberglass (chopped or continu-ous), carbon, aramid and other polymerics; or lignocellulosic-based fibers such as flax, jute
10、, kenaf, and hemp.1.4.4 A wide variety of chemical additives are added toplastic lumber formulations to serve numerous different pur-poses. Examples include colorants, chemical foaming agents,ultraviolet stabilizers, flame retardants, lubricants, anti-staticproducts, biocides, heat stabilizers, and
11、coupling agents1.5 The values stated in inch-pound units are to be regardedas the standard. The values given in brackets are for informa-tion only.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this sta
12、ndard to establish appro-priate safety and health practices and determine the applica-bility of regulator limitations prior to use.NOTE 1There is no similar or equivalent ISO standard.2. Referenced Documents2.1 ASTM Standards:2D 618 Practice for Conditioning Plastics for TestingD 883 Terminology Rel
13、ating to PlasticsD 2915 Practice for Evaluating Allowable Properties forGrades of Structural LumberD 5033 Guide for the Development of ASTM StandardsRelating to Recycling and Use of Recycled PlasticsD 5947 Test Methods for Physical Dimensions of SolidPlastics SpecimensE4Practices for Force Verificat
14、ion of Testing MachinesE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 Definitions: Definitions of terms applying to these testmethods appear in Terminology D 883 and Guide D 5033.3.1.1 plastic lumber, na manufactured product compose
15、dof more than 50 weight percent resin, and in which the product1These test methods are under the jurisdiction of ASTM Committee D20 onPlastics and are the direct responsibility of Subcommittee D20.20 on PlasticProducts (Section D20.20.01).Current edition approved February 1, 2005. Published February
16、 2005. Originallyapproved in 1997. Last previous edition approved in 2003 as D 6109 - 03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summ
17、ary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.generally is rectangular in cross-section and typically suppliedin sizes that correspond to
18、 traditional dimensional lumbersizes, may be filled or unfilled, and may be composed of singleor multiple resin blends.3.1.2 plastic lumber shape, nplastic lumber, which gen-erally is not rectangular in cross section3.1.3 resin, nsolid or pseudosolid organic material oftenof high molecular weight, t
19、hat exhibits a tendency to flowwhen subjected to stress, usually has a softening or meltingrange, and usually fractures conchoidally. (See TerminologyD 883.)3.1.3.1 DiscussionIn a broad sense, the term is used todesignate any polymer that is a basic material for plastics.4. Summary of Test Method4.1
20、 A specimen of rectangular cross section is tested inflexure as a beam either in a flat, or “plank,” mode (MethodA)or edgewise, or “joist,” mode (Method B) as follows:4.1.1 The beam rests on two supports and is loaded at twopoints (by means of two loading noses), each an equal distancefrom the adjac
21、ent support point. The distance between theloading noses (that is, the load span) is one-third of the supportspan (see Fig. 1; use of other distances for the load spans areaddressed in Appendix X1).4.1.2 The specimen is deflected until rupture occurs in theouter fibers or until a maximum outer fiber
22、 strain of 3 % isreached, whichever occurs first.5. Significance and Use5.1 Flexural properties determined by these test methods areespecially useful for research and development, quality control,acceptance or rejection under specifications, and special pur-poses.5.2 Specimen depth, temperature, atm
23、ospheric conditions,and the difference in rate of straining specified in Test MethodsA and B are capable of influencing flexural property results.6. Apparatus6.1 Testing MachineA properly calibrated testing ma-chine that is capable of operation at a constant rate of motionof the movable head and has
24、 the accuracy of 61% ofmaximum load expected to be measured. It shall be equippedwith a deflection measuring device. The stiffness of the testingmachine shall be such that the total elastic deformation of thesystem does not exceed 1 % of the total deflection of the testspecimen during testing, or ap
25、propriate corrections shall bemade. The load indication mechanism shall be essentially freefrom inertial lag at the crosshead rate used. The accuracy of thetesting machine shall be verified in accordance with PracticeE4.6.2 Loading Noses and SupportsThe loading noses andsupports shall have cylindric
26、al surfaces. In order to avoidexcessive indentation, of the failure due to stress concentrationdirectly under the loading noses, the radius or noses andsupports shall be at least 0.5 in. 12.7 mm for all specimens.If significant indentation or compressive failure occurs or isobserved at the point whe
27、re the loading noses contact thespecimen, then the radius of the loading noses shall beincreased up to 1.5 times the specimen depth (see Fig. 2).NOTE 2Test data have shown that the loading noses and supportdimensions are capable of influencing the flexural modulus values.Dimensions of loading noses
28、and supports must be specified in the testreport.7. Test Specimens7.1 The specimens shall be full size as manufactured, thencut to length for testing. The original outside surfaces shall beunaltered. The support span to depth ratio shall be nominally16:1.7.2 For Test Method A, flatwise or “plank” te
29、sts, the depthof the specimen shall be the thickness, or smaller dimension, ofthe product. For Test Method B, edgewise or “joist” tests thewidth becomes the smaller dimension and depth the larger. Forall tests, the support span shall be 16 (tolerance +4 and 2)times the depth of the beam. The specime
30、n shall be longenough to allow for overhanging on each end of at least 10 %of the support span. Overhang shall be sufficient to prevent thespecimen from slipping through the supports.8. Number of Test Specimens8.1 Five specimens shall be tested for each sample.FIG. 1 Loading DiagramNOTE 1(A) = minim
31、um radius = 12.7 mm; (B) = maximum radius =1.5 times the specimen depth.FIG. 2 Four Point Loading and Support Noses at Minimum andMaximum RadiusD 6109 0529. Conditioning9.1 Specimen ConditioningCondition the test specimensat 73.4 6 3.6F 23 6 2C and 50 6 5 % relative humidity fornot less than 40 h pr
32、ior to testing in accordance with ProcedureA of Practice D 618 for those tests where conditioning isrequired. In cases of disagreement, the tolerances shall be61.8F 61C and 62 % relative humidity.9.2 Test ConditionsConduct the tests in the StandardLaboratory Atmosphere of 73.4 6 3.6F 23 6 2C and 50
33、65 % relative humidity, unless otherwise specified in the refer-enced test methods or in these test methods. In cases ofdisagreement, the tolerances shall be 61.8F 61C and62 % relative humidity.10. Procedure10.1 Test Method A:10.1.1 Flatwise or “plank” Testing:10.1.2 Use an untested specimen for eac
34、h measurement.Measure the width of the specimen to a precision of 1 % of themeasured dimensions at several points along the productslength and record the average value. Measure the depth of thespecimen at several points and record the average value (seeTest Methods D 5947 for additional information)
35、.10.1.3 Determine the support span to be used as described inSection 7 and set the support span to within 1 % of thedetermined value.10.1.4 Calculate the rate of crosshead motion as follows,and set the machine as near as possible to that calculated ratefor a load span of one-third of the support spa
36、n:R 5 0.185ZL2/d (1)where:R = rate of crosshead motion, in./min mm/min,L = support span, in. mm,d = depth of the beam, in. mm, andZ = rate of straining of the outer fibers, in./in./min mm/mm/min. Z shall be equal to 0.01.In no case shall the actual crosshead rate differ from thatcalculated from Eq 1
37、, by more than 610 %.10.1.5 Align the loading noses and supports so that the axesof the cylindrical surfaces are parallel and the load span isone-third of the support span. Check parallelism by means of aplate containing parallel grooves into which the loading nosesand supports will fit when properl
38、y aligned. Center the speci-men on the supports, with the long axis of the specimenperpendicular to the loading noses and supports. The loadingnose assembly shall be of the type which will not rotate.10.1.6 Apply the load to the specimen at the specifiedcrosshead rate, and take simultaneous load-def
39、lection data.Measure deflection at the common center of the spans. Performthe necessary toe compensation (see Annex A1) to correct forseating and indentation of the specimen and deflections in themachine. Stress-strain curves shall be plotted to determine theflexural yield strength, modulus of elast
40、icity and secant modu-lus at 1 % strain.10.1.7 If no break has occurred in a specimen by the timethe maximum strain in the outer fibers has reached 0.03 in./in.mm/mm, discontinue the test (see Note 3 and Note 4). Thedeflection at which this strain occurs shall be calculated byletting r equal 0.03 in
41、./in. mm/mm as follows for a load spanof one-third of the support span:D 5 0.21 rL2/d (2)where:D = midspan deflection, in. mm,r = strain, in./in. mm/mm, andd = depth of the beam, in. mm.NOTE 3For some products the increase in strain rate provided underTest Method B is capable of inducing the specime
42、n to yield or rupture, orboth, within the required 3 % strain limit.NOTE 4If the product does not fracture at a maximum of 3 % strain,these test methods do not reveal true flexural strength.10.2 Test Method B:10.2.1 Edgewise or “Joist” Testing:10.2.2 Follow procedures of Test Method A, except that Z
43、,the rate of strain of the outer fibers, shall nominally be in therange of 0.002 and 0.003 in./in./min mm/mm/min.10.2.3 Lateral SupportsSpecimens tested in the edgewiseor “joist” position having a depth-to-width ratio greater thantwo are subject to lateral instability during loading, especiallyif th
44、e specimen breaks. For stability and safety during the test,lateral supports are needed while testing such specimens.Lateral support apparatus shall be provided at least at pointslocated about half-way between the reaction and the load point.Additional supports shall be used as required to providene
45、cessary stability and safety during the test. Each supportshall allow vertical movement without frictional restraint butshall restrict lateral deflection (See Fig. 3).11. Calculation11.1 Maximum Fiber StressWhen a beam is loaded inflexure at two central points and supported at two outer points,the m
46、aximum stress in the outer fibers occurs between the twocentral loading points that define the load span (See Fig. 1). Forrectangular cross-sections, this stress is calculated for any pointon the load-deflection curve for relatively small deflections bythe following equation for a load span of one-t
47、hird of thesupport span:S 5 PL/bd2(3)where:S = stress in outer fiber throughout load span, psi MPa,P = total load on beam at any given point on the load-deflection curve, lb N,L = support span, in. mm,b = width of beam, in. mm, andd = depth of beam, in. mm.NOTE 5Eq 3 applies strictly to products for
48、 which the stress is linearlyproportional to the strain up to the point of rupture and for which thestrains are small. Since this is not always the case, a slight error will beintroduced in the use of this equation.The equation will, however, be validfor comparison data and specification values up t
49、o the maximum fiberstrain of 3 % for specimens tested by the procedure herein described.11.2 Flexural Strength (Modulus of Rupture)The flexuralstrength is equal to the maximum stress in the outer fibers at themaximum load, load at rupture, or when the strain reaches 3 %,whichever occurs first. It is calculated in accordance with Eq 3D 6109 053by letting P equal the maximum load, the load at rupture, or theload corresponding to a deflection at 3 % strain, whicheveroccurs first.11.3 Stress at a Given StrainSome produ
