Modeling and parameter estimation of rheological objects for simultaneous reproduction of force and deformation

Abstract-Many deformable objects in our living life demonstrate rheological behaviors, such as human organs and tissues, clays and various food products. Rheological objects include both elastic and plastic properties. Due to the presence of residual (permanent) deformation, it is difficult to model rheological objects, especially to reproduce both force and residual deformation simultaneously. In this paper, a series of physical models was investigated for simulating rheological behaviors. Generalized formulations of the constitutive laws were derived for serial and parallel physical models, respectively. We found that the serial models are appropriate for formulating strain, whereas the parallel models allow a convenient calculation of stress. Analytical expressions of force and residual deformation were then derived for generalized parallel models. Theoretical discussions suggested the difficulty to reproduce both force and deformation simultaneously using linear physical models. A 2D FE (finite element) model was then formulated and an efficient method for estimating physical parameters were proposed by taking the advantages of analytical force expressions. Experimental results with commercial clay and Japanese sweets material were presented to validate our modeling and parameter estimation methods. A dual-moduli viscous element was also introduced to improve our FE model for reproducing rheological force and deformation simultaneously

Proceedings of SIRM 2023 - The 15th European Conference on Rotordynamics

It was our great honor and pleasure to host the SIRM Conference after 2003 and 2011 for the third time in Darmstadt. Rotordynamics covers a huge variety of different applications and challenges which are all in the scope of this conference. The conference was opened with a keynote lecture given by Rainer Nordmann, one of the three founders of SIRM “Schwingungen in rotierenden Maschinen”. In total 53 papers passed our strict review process and were presented. This impressively shows that rotordynamics is relevant as ever. These contributions cover a very wide spectrum of session topics: fluid bearings and seals; air foil bearings; magnetic bearings; rotor blade interaction; rotor fluid interactions; unbalance and balancing; vibrations in turbomachines; vibration control; instability; electrical machines; monitoring, identification and diagnosis; advanced numerical tools and nonlinearities as well as general rotordynamics. The international character of the conference has been significantly enhanced by the Scientific Board since the 14th SIRM resulting on one hand in an expanded Scientific Committee which meanwhile consists of 31 members from 13 different European countries and on the other hand in the new name “European Conference on Rotordynamics”. This new international profile has also been emphasized by participants of the 15th SIRM coming from 17 different countries out of three continents. We experienced a vital discussion and dialogue between industry and academia at the conference where roughly one third of the papers were presented by industry and two thirds by academia being an excellent basis to follow a bidirectional transfer what we call xchange at Technical University of Darmstadt. At this point we also want to give our special thanks to the eleven industry sponsors for their great support of the conference. On behalf of the Darmstadt Local Committee I welcome you to read the papers of the 15th SIRM giving you further insight into the topics and presentations