Fracture index 318 mechanics

Pharmaceutical compacts are complex structures that present difficult challenges when measuring their mechanical properties. Hiestand was a pioneer who quantified the compaction properties of pharmaceutical powders and (105-109) the result of his work are indices known as the Hiestand Tableting Indices. These indices are dimensionless numbers used to describe the mechanical properties and consolidation behavior of materials under compression and decompression. The three main Hiestand Tableting Indices are the bonding index, brittle fracture index BFl), and strain index. 

Measurement techniques of the elastic moduli, 388 Mechanical behaviour and failure, 819 Mechanical comfort, 879 Mechanical properties of solid polymers, 383 various materials, 389 Melt/Melting, 167, 700 elasticity, 316 expansion, 97 flow index, 801, 802 flow rate diagram, 801 fracture, 578 number, 579 strength, 799, 812 Merkel number, 59 Mesogenic groups, 34 in the main chain, 177 side-chain, 179 Mesogenic polymers, 172... 

There is clearly a need to investigate the mechanism of attrition to relate it to the fracture properties of the solids, and to develop a realistic attrition index , similar to that used for abrasion in cyclones. Such an index would indicate the relative importance of operating conditions and design variables such as inlet velocity, feed solids concentration or cyclone diameter. This could then be used in scale-up to predict (or minimize) the effect of the shape, the particle size distribution or the hardness and strength of the feed solids, if known, may allow such predictions without any experimental tests. Generally, better understanding of attrition and its relation to abrasion may lead to better equipment design and operation. 

Hu X J, Li W P, Cao D T Liu M C 2012. Index of Multiple Factors and Expected Height of Fully Mechanized Water Flowing Fractured Zone [J]. Journal of China Coal Society, 37(4) 613-620. 

Both, the filler content and the filler type influence the dispersion of the filler within the polymeric matrix. Usually, low filler content and fillers with low activity are considered to be factors being responsible for bad filler dispersion. The better the dispersion the higher is the dispersion index DI and the better the mechanical properties should be. However, similar to the tear resistance (see Chapter 4.1.2), also the fracture resistance is independent of the dispersion index DI for these polymer-filler combinations. 

ASME Code Section III at first used the fracture analysis diagram (FAD) for the prevention of brittle fracture. Linear elastic fracture mechanics was introduced in 1972 Summer Addenda, Appendix G. ASME Code Section XI Appendix A and NRC Federal Register lOCFR Part 50 were issued in 1973. In these codes and regulations, RTndt was introduced as an important index temperature to characterize the transition curve of fracture toughness. 

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