Thixotropy : Build-up and breakdown curves during flow

摘要: Thixotropic systems are usually characterized by measuring the stress transients resulting from sudden changes in shear rate. By using a procedure that takes into account transfer function of transducer on strain-controlled rheometer, initial part could be accessed. In this manner complete transient curves and accurate constant-structure recorded model system consisting fumed silica particles dispersed Newtonian medium. agreement with previously obtained jump data [Dullaert Mewis (2005b)], an viscoelastic response is detected precedes structural time effects either build-up or breakdown experiments. The effect flow history characteristic times shape investigated. It shown common assumptions thixotropic models, such as structure can single parameter existence exponential transients, do not generally hold. Although material quite complex, constants obey simple scaling law. present set very suitable for evaluation. Here, two representative those Houska Coussot, have been tested. parts well described. reasonably predicted, although properly modeled. For larger errors recorded.