ASTM_D_7891_-_15.pdf

Designation:D789115Standard Test Method forShear Testing of Powders Using the Freeman TechnologyFT4 Powder Rheometer Shear Cell1This standard is issued under the fixed designation D7891;the number immediately following the designation indicates the 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 method covers the apparatus and procedures formeasuring the incipient failure properties of a powder as afunction of the normal stress for a given level of consolidation.The method also allows the further determination of theunconfined yield strength,internal friction angles,cohesion,flow function,major principal stress and wall friction angle(with the appropriate wall coupon fitted to the correct acces-sory).1.2 These parameters are most commonly used for thedesign of storage hoppers and bins using industry standardcalculations and procedures.They can also provide relativeclassification or comparison of the flow behavior of differentpowders or different batches of the same powder if similarstress and shear regimes are encountered within the processingequipment.1.3 The apparatus is suitable for measuring the properties ofpowders with a maximum particle size of 1 mm.It is possibleto test powders which have a small proportion of particles of 1mm or greater,but they should be present in the bulk sample asno more than 5%of the total mass in samples with a normal(Gaussian)size distribution.1.4 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.4.1 The procedures used to specify how data are collected/recorded or calculated,in this standard are regarded as theindustry standard.In addition,they are representative of thesignificant digits that generally should be retained.The proce-dures used do not consider material variation,purpose forobtaining the data,special purpose studies,or any consider-ations for the users objectives;and it is common practice toincrease or reduce significant digits of reported data to becommensurate with these considerations.It is beyond the scopeof this standard to consider significant digits used in analysismethods for engineering design.1.5 UnitsThe values stated in SI units are to be regardedas standard.No other units of measurement are included in thisstandard.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 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:D653 Terminology Relating to Soil,Rock,and ContainedFluidsD2216 Test Methods for Laboratory Determination of Water(Moisture)Content of Soil and Rock by MassD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD6026 Practice for Using Significant Digits in GeotechnicalDataD6128 Test Method for Shear Testing of Bulk Solids Usingthe Jenike Shear CellD6682 Test Method for Measuring Shear Stresses of Pow-ders Using Peschl Rotational Split Level Shear TesterD6773 Test Method for Bulk Solids Using Schulze RingShear Tester3.Terminology3.1 DefinitionsFor definitions of common technical termsin this standard,refer to Terminology D653.3.2 Definitions of Terms Specific to This Standard:3.2.1 conditioning,vin powders,the process of homog-enizing the stress of a powder specimen by use of a specializedblade attachment.3.2.2 wall friction coupon,nin powders,a test piece usedin the wall friction test that is manufactured from a materialthat represents the material of construction of the silo/bin/hopper that stores the powder.4.Summary of Test Method4.1 Selection of the Appropriate Testing RegimeThe par-ticular consolidating stress level or levels used to evaluate the1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.24 on Characterizationand Handling of Powders and Bulk Solids.Current edition approved March 1,2015.Published March 2015.DOI:10.1520/D7891-15.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 flow properties of the powder will depend on the reason forgenerating the data,as outlined in Section 5,and shouldbroadly reflect the stresses that the powder will be subjected toin its processing environment.4.2 Preparation of the specimenThe specimen is added tothe test vessel and its mass determined using the instrumentsbuilt-in balance.The selected test program is then initiated andruns independently of the operator other than the interchangeof the spindle-mounted attachments for different sections of thetest.The powder f