1、Designation: D 2884 93 (Reapproved 2007)An American National StandardStandard Test Method forYield Stress of Heterogeneous Propellants by ConePenetration Method1This standard is issued under the fixed designation D 2884; the number immediately following the designation indicates the year oforiginal
2、adoption or, in the case of 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. Scope1.1 This test method2covers determination of the yieldstress of heterog
3、eneous propellants, both of the gel andemulsion types, containing from 0 to 70 % solid additives.1.2 The values stated in SI units are to be regarded as thestandard. In cases where materials, products, or equipment areavailable in inch-pound units only, SI units are omitted.1.3 This standard does no
4、t 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.2. Referenced Documents2.1 ASTM Standard
5、s:3D 2507 Terminology of Rheological Properties of GelledRocket Propellants43. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 penetration of a propellant, nThe depth, in tenths ofa millimetre that a standard cone penetrates the sample underprescribed conditions of weight, time,
6、and temperature.3.1.2 unworked penetration, nthe penetration at 298 K(77F) of a sample of the propellant which has received onlythe minimum disturbance in transfer from the sample can to agrease worker cup or dimensionally equivalent container. Thisshall be 76.2 6 0.3 mm (3 6 0.01 in.) in inside dia
7、meter and63.56 1.6 mm (2.5 6 0.06 in.) deep, as shown in Fig. 1.3.1.3 The conversion of penetration to yield stress has notbeen corrected for the displacement of the sample by thesubmerged portion of the cone. For this reason cup diameter iscritical, and any deviation from 76.2 6 0.3 mm (3 6 0.01 in
8、.)must be reported as a nonstandard condition.3.1.4 yield stressthe maximum shear stress that can beapplied without causing permanent deformation (see Terminol-ogy D 2507). Specifically in this test method, it is the weight ofthe 30-g mass cone-test rod assembly in dynes, corrected forbuoyancy, divi
9、ded by the calculated wetted area of the cone(that is, the area of the cone in contact with the propellant afterthe 5-s drop period).4. Summary of Test Method4.1 The penetration is determined at 298 K (77F) byreleasing the cone-test rod assembly from the penetrometer andallowing the assembly to drop
10、 for 5 s. The cone will beessentially at rest in less than this time, so that exact timing isnot critical.5. Significance and Use5.1 The yield stress is a measure of the forces required toinitiate and maintain flow from a storage vessel. If all thefactors are constant, the propellant with the lower
11、yield stresscan be removed more completely from the vessel.6. Apparatus6.1 Penetrometer, to measure the penetration of the standardcone in the propellant. The cone assembly or the table of thepenetrometer shall be adjustable to enable accurate placementof the cone on the level surface of the propell
12、ant whilemaintaining a zero reading on the indicator. The cone shouldfall, when released, without appreciable friction for at least42.0 mm but not more than 60.0 mm so the cone will not hit thebottom of the container. The instrument shall be provided withleveling screws to maintain the cone shaft in
13、 a vertical positionand a spirit level to determine the attitude of the instrument.6.1.1 A 15-g test rod shall be substituted for the regular47.5-g rod in accordance with the manufacturers instructions.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubrica
14、nts and is the direct responsibility of SubcommitteeD02.11 on Engineering Sciences of High Performance Fluids and Solids. ASTMCommittee F07 on Aerospace and Aircraft maintains a continued interest in this testmethod and will make use of it in the future.Current edition approved May 1, 2007. Publishe
15、d June 2007. Originallyapproved in 1970. Last previous edition approved in 2002 as D 2884 93 (2002).2This test method is identical in substance with the JANNAF method, “Hetero-geneous Propellant Characterization, Part III, Procedure for Measuring Yield Stressof Heterogeneous Propellants,” published
16、by the Chemical Propulsion InformationAgency, July 1969, Johns Hopkins University, Applied Physics Laboratory, JohnsHopkins Rd., Laurel, MD 20810.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards
17、 volume information, refer to the standards Document Summary page onthe ASTM website.4Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.2 Cone, of the dimensions shown in Fig. 2.NOTE 1Some cones have correct dimensions and
18、weight (15.0 g) butreact with hydrazine gels. The user should plan to have one made to order.6.3 Grease Worker Cup, or equivalent container. The cupshall be made of material known to be compatible with allpropellants which are to be tested in it. Construction may betwo-piece as shown in Fig. 1, usin
19、g a silver solder or brazewhich meets the compatibility requirement to seal the joint.Several users have had cups machined in one piece from barstock, or from a rough casting.6.4 Water Bath, capable of regulation to 298 6 0.5 K (77 61F). For unworked penetrations, means must be provided forprotectin
20、g the propellant surface from atmosphere moisture.NOTE 2A constant-temperature room or an air bath may be usedinstead of the water bath. A special atmosphere may be required for somepropellant samples.6.5 Spatula, corrosion-resistant, square-ended, having a stiffblade 30 mm wide and at least 150 mm
21、long.7. Procedure for Unworked Penetration7.1 Test SpecimenSufficient propellant test specimen (atleast 450 g) to overfill the cup of the standard grease workershall be required. If the anticipated penetration is above 200, atleast three times the amount needed to fill the cup shall berequired.7.2 P
22、reparing Test Specimen for MeasurementPlace theempty assembled grease worker or suitable container of equalinside dimensions and an appropriate amount of the sample ina sealed container in the water bath maintained at 298 K (77F)for sufficient time to bring the temperature of the sample to 2986 0.5
23、K (77 6 1F). Transfer from the container a portion ofthe sample, preferably in one lump, to overfill the cup of thegrease worker or container of equal inside dimensions. Makethis transfer in such a manner that the sample will be workedas little as possible. Jar the container to drive out trapped air
24、and pack the sample with the spatula, with as little manipula-tion as possible to obtain a capful without air pockets. Scrapeoff the excess sample extending above the rim by moving theblade of the spatula, held inclined toward the direction ofmotion at an angle of 45 across the rim of the cup. Do no
25、tperform any further leveling or smoothing of the surfacethroughout the determination of unworked penetration, anddetermine the measurement immediately.7.3 Cleaning Cone and ShaftClean the penetrometer conecarefully before each test. Bending of the test rod can beavoided by holding it securely in it
26、s raised position whilecleaning. Do not permit grease, oil, or propellant on the testrod, as they can cause drag on the assembly. Do not rotate thecone, as this may cause wear on the aluminum test rod.7.4 Penetration Measurement:7.4.1 Place the cup on the penetrometer table, makingcertain that it ca
27、nnot teeter. Set the mechanisms to hold thecone in the zero position, and adjust the apparatus carefully sothat the tip of the cone just touches the surface at the center ofthe test sample. Watching the shadow of the cone tip is an aidto accurate setting. Release the test rod rapidly, and allow it t
28、odrop for 5.0 6 0.5 s. The clutch jaws must not drag on theshaft. Gently depress the depth gage rod until stopped by thelower stop, and read the penetration from the indicator.7.4.2 If the sample has a penetration over 200, center thecone carefully in the container; this sample can then be used foro
29、nly one test. If the sample has a penetration of 200 or less,perform three tests in a single container, spacing these tests onthree radii 120 apart and midway between the center and sideof the container so that the cone will neither strike the side ofthe container nor impinge on the disturbed area m
30、ade in aprevious test.7.5 Additional TestingMake a total of three tests on thesample (either in three containers or in one, as described in7.4), unless the first reading is greater than 420.8. Report8.1 Ordinary SamplesThe three test results shall be aver-aged and used to calculate the yield stress,
31、 Sy, as follows:Sy598130.0 1.0473 106! P 107.4!3d 0.198d!4.44 3 104P 107.4!21 1.260(1)where:P = penetration, tenths of a mm,d = density, g/cm3, andSy= yield stress, dynes/cm2(Note 5).S8y= Sy/10 = yield stress, Pa.8.2 Excessively Soft SamplesIf the penetration exceeds420, the propellant will overflow
32、 into the cone. This invalidatesthe use of the equation, and the sample shall be reported as toosoft.8.2.1 If the material from which the cone is made is otherthan magnesium, this fact shall be stated in the report alongwith sufficient information to permit identification of thematerial used. It is
33、known that slippage along the cone surfacecan take place with surfaces which are highly lipophilic, suchas polyethylene, PTFE (polytetrafluoroethylene), and so forth.Such cones should be used only when the purpose of the test isto determine an apparent yield stress in relation to a specificstructura
34、l material or lining.9. Precision and Bias9.1 The precision of the method as determined by statisticalexamination of interlaboratory results is as follows:NOTE 1This cup is dimensionally equivalent to the grease workercup.FIG. 1 Penetrometer CupD 2884 93 (2007)29.1.1 RepeatabilityThe difference betw
35、een two test re-sults, obtained by the same operator with the same apparatusunder constant operating conditions on identical test material,would in the long run, in the normal and correct operation ofthe test method, exceed the following values only in one casein twenty:40 %9.1.2 ReproducibilityThe
36、difference between two singleand independent results obtained by different operators work-ing in different laboratories on identical test material would, inthe long run, in the normal and correct operation of the testmethod, exceed the following values only in one case intwenty:75 %NOTE 1Tolerances
37、on all fractional dimensions shall be116 in.NOTE 2The total mass of the cone shall be 15.00 + 0.05 g and the total mass of its movable attachments shall be 15.00 6 0.05 g.NOTE 3Table of Metric Equivalentsin. mm in. mm in. mm in. mm0.014 0.35618 3.18 0.331 8.407 1.136 28.8540.016 0.406532 3.98 0.586
38、14.884 1.156 29.362116 1.5914 6.35 0.590 14.986 218 53.980.122 3.10516 7.9458 15.88 2.550 64.770.125 3.18 0.329 8.357 118 28.575 2.570 65.28FIG. 2 Magnesium Penetrometer ConeD 2884 93 (2007)39.2 BiasNo general statement is made on the bias forthis test method since the results cannot be compared wit
39、h anaccepted reference material.10. Keywords10.1 cone penetration; heterogeneous propellant; propel-lants; yield strengthASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expres
40、sly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised,
41、 either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may at
42、tend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 2884 93 (2007)4
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