Mechanical data from force curve analysis

Table 2. Mechanical Data Obtained from Force Curve Analysis...

Universal testing machines (UTMs) allow computer readout and analysis of force-time plots. Special software displays graphs for maximum normal and shear forces during compression tests, as well as creep and stress relaxation curves. Mechanical compressibility and breaking load under tension can also be determined from stress-strain data by using UTMs. 

As a final note is important to bear in mind that solid-fluid separations are governed by mechanical forces, such as the gravity force, and so it is important that the screen analysis data on the relevant streams used to derive a grade efficiency curve had been measured avoiding transformations. The use of a particle sizer that measures the relevant particle size directly, that is, any method measuring directly the Stokes diameter should be preferred over a method relying on transforming size distributions from number to surface, or surface to mass, and so on. 

By combining optimal cantilever parameters and experimental conditions one can obtain reliable force distance data which is appropriate for further contact mechanics analysis for a wide selection of polymeric materials. Both Sneddon s and Hertzian models of elastic contact give consistent results in the range of indentation depth up to 100 nm. Close correlation is observed between elastic moduli determined by SFM in compression mode (approaching cycle) and measured values for bulk materials. As shown, for elastic materials force-distance curves can be used for evaluation of tensile elastic moduli from retracing cycle. For rubber material, the latest is in a good agreement with measuremente in compression mode. 

---