ASTM D8081-17

5.1 A large number of industrial processes involve transfer and feeding of bulk solids, and the ability of such materials to flow in a controlled manner during these operations is critical to product quality.

5.2 Direct shear cells are among the most important methods for measuring the flow properties of bulk solids in industrial applications for bulk solids handling.

5.3 Direct shear cells have many advantages over simpler methods of measuring bulk solids flow properties, but their operation is more complex and the procedures for their use must be carefully controlled to produce accurate and reproducible data.

5.4 The three most popular direct shear cell types are: Translational (D6128), Annular (D6773), and Rotational (D6682 and D7891).

5.5 From shear cell data, a wide variety of parameters can be obtained, including the yield locus representing the shear stress to normal stress relationship at incipient flow, angle of internal friction, unconfined yield strength, cohesion, and a variety of related parameters such as the flow function.

5.6 In addition, these three direct shear cells can be set up with wall coupons to measure wall friction.

5.7 When the shear cell data are combined with unconfined yield strength, wall friction data, and bulk density data, they can be used for bin and hopper evaluation and design.

1.1 This guide covers theory and principles for obtaining reliable and accurate bulk solids flow data using a direct shear cell. It includes characteristics and limitations of the three most popular direct shear cell types: Translational (D6128), Annular (D6773), and Rotational (D6682 and D7891).

1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measure are included in this standard.

1.3 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project’s many unique aspects. The word “Standard” in the title of this document means only that the document has been approved through the ASTM consensus process.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.