1、Designation: D7290 06 (Reapproved 2017)Standard Practice forEvaluating Material Property Characteristic Values forPolymeric Composites for Civil Engineering StructuralApplications1This standard is issued under the fixed designation D7290; the number immediately following the designation indicates th
2、e year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the procedures for computingc
3、haracteristic values of material properties of polymeric com-posite materials intended for use in civil engineering structuralapplications. The characteristic value is a statistically-basedmaterial property representing the 80 % lower confidencebound on the 5th-percentile value of a specified popula
4、tion.Characteristic values determined using this standard practicecan be used to calculate structural member resistance values indesign codes for composite civil engineering structures and forestablishing limits upon which qualification and acceptancecriteria can be based.1.2 This standard does not
5、purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.3 This international standard was develo
6、ped in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Docum
7、ents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD3878 Terminology for Composite MaterialsD5055 Specification for Establishing and Monitoring Struc-tural Capacities of Prefabricated Wood I-JoistsD5457 Specification for Computing Reference Resistance ofWood-Based Materials and Structural
8、Connections forLoad and Resistance Factor DesignD5574 Test Methods for Establishing Allowable MechanicalProperties of Wood-Bonding Adhesives for Design ofStructural JointsE6 Terminology Relating to Methods of Mechanical TestingE178 Practice for Dealing With Outlying ObservationsE456 Terminology Rela
9、ting to Quality and Statistics2.2 Other Document:MIL-Handbook-17 Polymer Matrix Composites, Volume 1,Revision F33. Terminology3.1 DefinitionsTerminology D3878 defines terms relatingto high-modulus fibers and their composites. TerminologyD883 defines terms relating to plastics. Terminology E6 defines
10、terms relating to mechanical testing. Terminology E456 definesterms relating to statistics. In the event of a conflict betweenterms, Terminology D3878 shall have precedence over theother documents.3.2 Definitions of Terms Specific to This Standard:3.2.1 characteristic valuea statistically-based mate
11、rialproperty representing the 80 % lower confidence bound on the5th-percentile value of a specified population. The character-istic value accounts for statistical uncertainty due to a finitesample size.3.2.1.1 DiscussionThe 80 % confidence bound and 5th-percentile levels were selected so that compos
12、ite materialcharacteristic values will produce resistance factors for Loadand Resistance Factor Design similar to those for other civilengineering materials (see Refs 1 and 2).43.2.1.2 DiscussionThe term “characteristic value” isanalogous to the term “basis value” used in the aerospaceindustry where
13、 A- and B-basis values are defined as the 95 %1This practice is under the jurisdiction of ASTM Committee D30 on CompositeMaterials and is the direct responsibility of Subcommittee D30.10 on Compositesfor Civil Structures.Current edition approved Aug. 1, 2017. Published September 2017. Originallyappr
14、oved in 2006. Last previous edition approved in 2011 as D729006(2011). DOI:10.1520/D7290-06R17.2For 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 Documen
15、t Summary page onthe ASTM website.3Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http:/www.access.gpo.gov.4The boldface numbers in parentheses refer to the list of references at the end ofthis standard.Copyrig
16、ht ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of Internationa
17、l Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1lower confidence bound on the lower 1 % and 10 % values ofa population, respectively.3.2.2 data confidence factor, a factor that is used toadjust the sample nominal value for u
18、ncertainty associated withfinite sample size.3.2.3 nominal valuethe 5th percentile value of the datarepresented by a probability density function.3.2.4 outlieran outlying observation, or “outlier,” is onethat deviates significantly from other observations in thesample in which it occurs.4. Significa
19、nce and Use4.1 This practice covers the procedures for computingmaterial property characteristic values for polymeric compositematerials intended for use in civil engineering structuralapplications. A characteristic value represents a statisticallower bound on the material property structural member
20、resistance factors for civil engineering design codes for com-posite structures.4.2 This practice may be used to obtain characteristic valuesfor stiffness and strength properties of composite materialsobtained from measurements using applicable test methods.5. Sampling5.1 Samples selected for analys
21、is shall be representative ofthe material property population for which the characteristicvalues are to be calculated.5.2 The minimum number of samples shall be specified indesign codes that reference this standard.NOTE 1Section 5.3.1 of the building code requirements for structuralconcrete (ACI 318
22、-05) requires at least 30 samples to determine thestandard deviation of concrete compressive strength for a new batch plantbut allows a reduction to a minimum of 15 samples, provided that amodification factor is used to increase the standard deviation if less than30 samples are used (Ref 3). For woo
23、d, Specification D5457 requires aminimum of 30 samples for computing the reference resistance of woodbased materials and structural connections for Load and Resistance FactorDesign, and states that extreme care must be taken during sampling toensure a representative sample for sample sizes less than
24、 60. The bendingcapacity of wood I-joists can be determined either by analysis orempirically by testing (Specification D5055). If the capacity is determinedby analysis, a minimum of ten confirming tests is required at each of theextremes of flange size, allowable stress, and joist depth. Test Method
25、sD5574 requires 60 samples for establishing allowable tensile and shearstresses of wood-bonding adhesives in structural joints. Fifty-nine of thesamples are actually tested, with the last held in reserve.6. Procedure6.1 Mean and Standard DeviationCalculate the averagevalue and standard deviation for
26、 the measured material prop-erty:x 5S(i51nxiDn(1)sn215 S(i51nxi2 x!2D/n 2 1! (2)where:x = sample mean (average),sn-1= sample standard deviation,n = number of specimens, andxi= measured or derived property.6.2 Detection of Outlying ObservationsThe data beinganalyzed shall be screened for outliers usi
27、ng the MaximumNormed Residual (MNR) method. A value is declared to be anoutlier by this method if it has an absolute deviation from thesample mean which, when compared to the sample standarddeviation, is too large to be due to chance. This method detectsone outlier at a time; hence the significance
28、level pertains to asingle decision.NOTE 2Practice E178 provides several methods for statisticallyanalyzing a dataset for outliers. The MNR method is used here because itis a simple method that is unlikely to be miscalculated, misinterpreted ormisapplied.NOTE 3An outlying observation may be an extrem
29、e manifestation ofthe random variability of the material property value. For such a case, thevalue should be retained and treated as any other observation in thesample. However, the outlying observation may be the result of a grossdeviation from prescribed experimental procedure or an error in calcu
30、lat-ing or recording the numerical value of the data point in question. Whenthe experimentalist can document a gross deviation from the prescribedexperimental procedure, the outlying observation may be discarded,unless the observation can be corrected in a rational manner.6.2.1 Outlier Criteria for
31、Single SamplesFor a sample ofsize n, arrange the data values x1, x2, x3, .xn in order ofincreasing magnitude with xnbeing the largest value. Calculatethe MNR statistic as the maximum absolute deviation from thesample mean divided by the sample standard deviation:MNR 5 maxS?xi2 x?sn21D(3)6.2.1.1 Calc
32、ulate the critical MNR value, CV, based on a5 % significance level using the following approximation:CVS2 285=nD2(4)6.2.1.2 There are no outliers in the sample of observations ifthe calculated MNR statistic is smaller than the critical valueCV, that is MNR CV.IftheMNR statistic is found to begreater
33、 than the critical value, then the MNR shall be denoteda possible outlier. The possible outlier shall be investigated todetermine whether there is an assignable cause for removing itfrom the data set. If no cause can be found, it shall be retainedin the data set. If an outlier is clearly erroneous,
34、it can beremoved after careful consideration provided that the subjec-tive decision to remove the value is documented as part of thedata analysis report. If an outlier is removed from the dataset,the sample mean and standard deviation shall be recalculated.This process shall be repeated until the sa
35、mple of observationsbecomes outlier-free.NOTE 4Eq 4 is an approximate nonlinear regression of critical valuespresented in the MIL-Handbook 17 with a correlation coefficient of 0.998.6.3 Material Property DistributionFor this standardpractice, the material property value probability distributionfunct
36、ion is assumed to follow the two-parameter Weibulldistribution (Ref 2) expressed in the form:fx! 5SDSxD21expF2SxDG(5)D7290 06 (2017)2where: = the shape parameter and is the scale parameter, and = the scale parameter.NOTE 5The basis for selecting the Weibull distribution is given inRefs 2 and 4.6.4 M
37、aximum Likelihood Parameter Estimation:6.4.1 Calculate the maximum likelihood estimate, ,oftheWeibull shape parameter by numerically solving the equa-tion:(i51nxilnxi!(i51nxi2121n(i51nlnxi! 5 0 (6)6.4.2 Calculate the maximum likelihood estimate, , of theWeibull scale parameter using: 5S(i51nxinD1(7)
38、where:n = the number of data values used in the analysis.6.4.3 Calculate the coefficient of variation of the propertyfrom the equation:COV 5S112D2 2S111DS111D(8)where: = the gamma function.6.5 Nominal ValueCalculate the nominal value of thesample data as the 5th-percentile of the two-parameter Weibu
39、lldistribution, using:x0.055 0.0513#1 (9)6.6 Characteristic ValueCalculate the characteristic valuefor the material property as the 80 % confidence bound on the5th-percentile value using:xchar5 x0.05(10)In which the data confidence factor, , accounts for theuncertainty associated with a finite sampl
40、e size. This factor isa function of coefficient of variation, sample size, and referencepercentile. Table 1 provides data confidence factors appropriatefor lower fifth-percentile estimates.7. Report7.1 Report the following information, or references pointingto other documentation containing this inf
41、ormation, to themaximum extent applicable:7.1.1 The sample size and individual data values,7.1.2 Any data values which were determined to be outliersand excluded from the data analysis, along with the rationalefor excluding the outlier,7.1.3 The sample nominal value and coefficient of variation,7.1.
42、4 The maximum likelihood estimates of the Weibullshape and scale factors for the sample,7.1.5 The data confidence factor, , and7.1.6 The sample characteristic value.TABLE 1 Data Confidence Factor, , on the 5th-Percentile Value for a Weibull Distribution with 80 % ConfidenceA(Refs 3 and 4)COVn 0.05 0
43、.10 0.15 0.20 0.25 0.30 0.40 0.5010 0.950 0.899 0.849 0.800 0.752 0.706 0.619 0.54111 0.953 0.906 0.860 0.814 0.769 0.725 0.642 0.56712 0.956 0.913 0.869 0.826 0.783 0.741 0.662 0.58913 0.959 0.918 0.876 0.835 0.795 0.755 0.679 0.60914 0.961 0.922 0.883 0.844 0.805 0.767 0.694 0.62615 0.963 0.926 0.
44、889 0.851 0.814 0.778 0.707 0.64116 0.965 0.929 0.894 0.858 0.822 0.787 0.719 0.65518 0.968 0.935 0.902 0.869 0.836 0.803 0.739 0.67820 0.970 0.940 0.909 0.878 0.847 0.816 0.755 0.69822 0.972 0.944 0.914 0.885 0.856 0.827 0.769 0.71424 0.974 0.947 0.919 0.891 0.864 0.836 0.781 0.72826 0.975 0.949 0.
45、923 0.897 0.870 0.844 0.791 0.74128 0.976 0.952 0.927 0.902 0.876 0.851 0.800 0.75230 0.977 0.954 0.930 0.906 0.882 0.857 0.809 0.76132 0.978 0.956 0.933 0.910 0.886 0.863 0.816 0.77034 0.979 0.957 0.935 0.913 0.890 0.868 0.822 0.77836 0.980 0.959 0.938 0.916 0.894 0.872 0.828 0.78538 0.980 0.960 0.
46、940 0.919 0.897 0.876 0.833 0.79140 0.981 0.962 0.942 0.921 0.901 0.880 0.838 0.79742 0.982 0.963 0.943 0.924 0.904 0.883 0.843 0.80344 0.982 0.964 0.945 0.926 0.906 0.886 0.847 0.80846 0.983 0.965 0.946 0.928 0.909 0.889 0.851 0.81348 0.983 0.966 0.948 0.929 0.911 0.892 0.854 0.81750 or more 0.984
47、0.967 0.949 0.931 0.913 0.895 0.858 0.821ALinear interpolation is permitted. For COV values below 0.05 ( 24.95), the values for COV = 0.05 shall be used.D7290 06 (2017)3REFERENCES(1) Ellingwood, B. R., “Toward Load and Resistance Factor Design forFiber-Reinforced Polymer Composite Structures,” ASCE
48、Journal ofStructural Engineering, Vol 129, No. 4, 2003, pp. 449-458.(2) Zureick, A., Bennett, R. M., and Ellingwood, B. R., “StatisticalCharacterization of Fiber-Reinforced Polymer Composite MaterialProperties for Structural Design,” ASCE Journal of StructuralEngineering, August, 2006, Vol 132 , No.
49、 8, pp. 1320-1327.(3) ACI 318-05, “Building Code Requirements for Structural Concreteand Commentary,” American Concrete Institute, Farmington Hills,MI, 2005.(4) Zureick, A., Bennett, R. M., and Alqam, M., “Acceptance TestSpecifications and Guidelines for Fiber-Reinforced Polymeric BridgeDecks,” Final Report, Volume 2: Determination of Material PropertyCharacteristic Values of Fiber-Reinforced Polymeric Composites,prepared for the Federal HighwayAdministration (FHWA), StructuralEngineering, Mechan
