Amir Zanj

An energy-based viscoelastic model for multi-physical systems: A Bond graph approach

Understanding the true nature of viscoelastic behaviors in multi-physical systems has always been a challenging issue in the system dynamic investigations, as each existing physical subdomain of the system may follow a different attenuation pattern during the dynamic process. In this study, to generate a viscoelastic model suitable for multi-physical domain dynamic investigations, a physical combined viscoelastic model is proposed. To this aim, by means of the Bond graph approach, the physical model of the embedded dispersive mechanisms of the conventional viscoelastic models is first generated. An energy-based combined viscoelastic model is then proposed by including the obtained dissipative mechanisms into the relative subdomains of an elastic domain. The obtained results indicate that the proposed energy-based viscoelastic model is able to capture a variety of viscoelastic behaviors in the system with respect to the true physical nature of the system.

Domain-Independent Thermoviscoelastic Modeling Framework: A Physical Approach on Thermoelasticity by Bond Graph

Controlling the thermomechanical behavior of a multiphysical system has always been a challenging issue, because the general behavior of the system in this case is a result of complex energetic tra...

Multiple-field systems dynamic modeling, part III: Fluid field physical decomposition

In this study, a new fundamental modeling framework for compressible fluid field is proposed by means of which a two-way dynamic coupling between the solid and fluid fields can be attainable for identically-modeled solid field. To this aim, using the physical decomposition framework proposed in [1], the general dynamics of the fluid field are extracted from the conserved reversible and irreversible interactions of the energetic components of the involved physical domains. The physically-decomposed power network of the fluid field makes it possible to control and manage the data transactions of each physical domain of the field individually. The added capabilities of the proposed physical modeling approach provide a novel feature that can be used for multiple-field system dynamic studies by providing the possibility of continuous data transactions between coupled fields.

Multi-physical system variable DoF modeling an investigation on hydro-control device start process

In this paper, a feasibility study on modeling the multi-physical dynamic behaviors of the start period of hydro-mechanical control devices is presented. Using a novel multi-model Bond graph approach, a nonlinear, variable degree-of-freedom, state-space model is developed for a typical pressure regulator during its start period. Simulation studies demonstrate the essential physical behavior of the regulator during the transient, and confirm the integrity of the resulting nonlinear model of the system.

Dynamic analysis of thermo-viscoelasticity in multi-physical systems: A bond graph approach

Controlling thermo-mechanical behavior of multi-physical systems has always been a challenge, as the general system behavior in this case is a result of complex energetic transactions between the system existing subdomains. In this study we propose a novel thermo-viscoelastic model in which the thermo-mechanical behavior of the system is generated from the interactive dynamics of its involving subdomains. The proposed model provides an energetic structure with which the general behavior of the system is obtained for the constructive dynamics of each subdomain. This capability of the model leads to an automatic capturing of the thermo-mechanical phenomena inside the system. The obtained simulation results for a simple beam structure demonstrate the impacts of the internal dynamics on the observable behavior of the system, and prove the capability of the model in covering a wide range of thermo-mechanical behavior including material softening, vibrational heating, dilation, relaxation, conduction, and damping.

Multiple-field systems dynamic modeling, part IV: Fluid-structure-interaction physical coupling

In this study, a new fundamental modeling framework for coupling the solid and fluid fields is proposed with which the system dynamics are generated with respect to the internal energetic interactions between the system existing physical domains. To this aim, the physical-decomposition modeling techniques, developed respectively for the solid [1] and fluid [2] fields, are implemented. By considering the conserved power transactions between the two fields, the reversible and irreversible intra-connections are then generated. Owing to the domain-independency of the generated models, the total conserved power transactions between the two fields are defined distinguishably from the power transactions of the corresponding physical domains of the two fields in the form of handshaking. This strategy broadens the physical insights of power transactions in fluid-structure-interaction (FSI) investigations. The added capabilities of the proposed framework provide a novel feature into the FSI dynamic modelling that can, not only, broaden the valid range of the ensuring model but, more importantly, offer a unique opportunity for capturing and revealing the unknown FSI phenomena previously hidden using existing classical physical knowledge.

Energy-Based Compressible Convective Model Proper for Aerothermoelastic Dynamic Investigations

In this study, an attempt is made to relate the dynamics of a compressible convective fluid to the energetic interactions between the existing physical subdomains of the field. Accordingly, the general dynamics of the system are presented in the form of a set of distinguishable and meaningful relations between the reversible and irreversible interactions of the energy components of the subdomains. To this aim, the energetic decomposition of the fluid field is first developed from conservation equations. By defining multidimensional energetic components, possible reversible and irreversible connections between the subdomains are then clarified, with which distinctive energy transformation between the subdomains and energy transportation within the fluid field become identifiable. Finally, the general energetic network of the system is achieved, which demonstrates the power transactions within the system in a conservative manner. The model thus generated is capable of presenting the complex behavior of the ...