scholarly journals Existence, regularity and weak-strong uniqueness for three-dimensional Peterlin viscoelastic model

2022 ◽  
Vol 20 (1) ◽  
pp. 201-230
Author(s):  
Aaron Brunk ◽  
Yong Lu ◽  
Mária Lukáčová-Medviďová
Keyword(s):  
Viscoelastic Model ◽  
Three Dimensional ◽  
Strong Uniqueness

Three-dimensional numerical simulation of the filling stage in resin infusion process

2016 ◽  
Vol 50 (29) ◽  
pp. 4171-4186 ◽  
Author(s):  
Bo Yang ◽  
Qian Tang ◽  
Shilong Wang ◽  
Tianguo Jin ◽  
Fengyang Bi
Keyword(s):  
Viscoelastic Model ◽  
Three Dimensional ◽  
Mass Conservation ◽  
Great Difficulty ◽  
Resin Flow ◽  
Resin Infusion ◽  
Thickness Change ◽  
Geometry Model ◽  
Filling Stage ◽  
Dimensional Simulation

Resin infusion (RI) process has been widely used for manufacturing composite parts. The variation of preform thickness brings great difficulty to the three-dimensional simulation of the filling stage. To accurately simulate the preform thickness change and resin flow during resin infusion, precise preform compaction models and dynamically changing geometry models need to be adopted. At present, resin flow is usually considered as two-dimensional and simple compaction models are employed to simplify the simulation, which degrades the prediction accuracy seriously. In this paper, general equations to describe the resin flow in the changing thickness cavity are developed, and the viscoelastic model is adopted which can fully express the dynamic characteristics of the preform compaction. To avoid solving the coupled resin flow/preform deformation equations directly, the volume of fluid method and the dynamic mesh model are employed to implement the tracking of the flow front and updating of cavity geometry model. The resin storage and release induced by porosity variations are adjusted by a master-slave element method to ensure mass conservation. Two simulation examples are carried out to demonstrate the capability of the above approach. The applicability of the approach on arbitrary complex domains and sequential injection strategy is also verified.

Nanofinishing of Microslots on Surgical Stainless Steel by Abrasive Flow Finishing Process: Experimentation and Modeling

2018 ◽  
Vol 6 (2) ◽  
Author(s):  
Sachin Singh ◽  
Deepu Kumar ◽  
Mamilla Ravi Sankar ◽  
Kamlakar Rajurkar
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Critical Role ◽  
Viscoelastic Model ◽  
Three Dimensional ◽  
Drug Eluting Stent ◽  
Initial Surface ◽  
Technological Advancement ◽  
Drug Eluting ◽  
Abrasive Flow Finishing

Miniaturization of components is one of the major demands of the today's technological advancement. Microslots are one of the widely used microfeature found in various industries such as automobile, aerospace, fuel cells and medical. Surface roughness of the microslots plays critical role in high precision applications such as medical field (e.g., drug eluting stent and microfilters). In this paper, abrasive flow finishing (AFF) process is used for finishing of the microslots (width 450 μm) on surgical stainless steel workpiece that are fabricated by electrical discharge micromachining (EDμM). AFF medium is developed in-house and used for performing microslots finishing experiments. Developed medium not only helps in the removal of hard recast layer from the workpiece surfaces but also provides nano surface roughness. Parametric study of microslots finishing by AFF process is carried out with the help of central composite rotatable design (CCRD) method. The initial surface roughness on the microslots wall is in the range of 3.50 ± 0.10 μm. After AFF, the surface roughness is reduced to 192 nm with a 94.56% improvement in the surface roughness. To understand physics of the AFF process, three-dimensional (3D) finite element (FE) viscoelastic model of the AFF process is developed. Later, a surface roughness simulation model is also proposed to predict the final surface roughness after the AFF process. Simulated results are in good agreement with the experimental results.

scholarly journals Modified stepped scheme for modelling the dynamic behaviour of 3D poroviscoelastic solids

2018 ◽  
Vol 174 ◽  
pp. 02019
Author(s):  
Leonid Igumnov ◽  
Aleksandr Ipatov ◽  
Svetlana Litvinchuk
Keyword(s):  
Dynamic Behaviour ◽  
Boundary Integral Equations ◽  
Viscoelastic Model ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Boundary Integral ◽  
Dynamic Responses ◽  
Elastic Model ◽  
Weakly Singular Kernel ◽  
Soil Medium

The problem of the dynamic response of a soil medium under different kinds of loads is of significant importance in various areas of engineering, especially in connection with structures. The present paper is dedicated to the modification of the numerical approach for modelling the dynamic behaviour of three dimensional poroviscoelastic solids. The basic equations for fluid-saturated porous media proposed by Biot are modified by replacing the classical linear elastic model of the solid skeleton with the viscoelastic model. Classical models of viscoelasticity are employed, such as Kelvin-Voight model, standard linear solid model and model with weakly singular kernel. Boundary integral equations method is applied to solving three-dimensional boundary-value problems. Stepped schemes modifications based on the linear and quadratic approximation of function are employed. A numerical example of poroviscoelastic rod under Heaviside type load is provided. A problem of a poroviscoelastic cube with a cavity subjected to a normal internal pressure is considered. The comparison of dynamic responses when poroviscoelastic material is described by different viscoelastic models is presented.

Three-dimensional pulse response of curved composite sandwich panel with compressible core using non-linear higher-order theory

2020 ◽  
pp. 109963622098008
Author(s):  
Seyed Ali Ahmadi ◽  
Mohammad Hadi Pashaei ◽  
Ramazan-Ali Jafari-Talookolaei
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Sandwich Panel ◽  
Viscoelastic Model ◽  
Three Dimensional ◽  
Higher Order ◽  
Computer Hardware ◽  
Computational Time ◽  
Damping Factor ◽  
Non Linear

In this paper, the dynamic response of cylindrical sandwich panels with compressible core is obtained using the extended non-linear higher-order sandwich panel theory. It is assumed that the sandwich panel has simply supported boundary at all edges and is consisted of orthotropic face sheets and viscoelastic core layer. To describe the mechanical properties of the viscoelastic foam core, the Kelvin-Voigt linear viscoelastic model was applied. Three-dimensional linear equations of motions were used to describe the sandwich panel deformations. The effects of various parameters including the panel span, core and facing thickness, the viscous damping factor, pulse duration, and maximum pressure on the dynamic response of the sandwich cylindrical panel are studied. The results obtained from present method are compared with finite element solutions and those reported in the literature, and consequently, agreement among the results could be observed. The results shown that applied viscoelastic model has a signification effect on the panel response and reduces the magnitude of vibrations. The presented programming code (DQ) needs less computational time and computer hardware capacity and is faster than finite element solution.

scholarly journals Mechanotransmission in endothelial cells subjected to oscillatory and multi-directional shear flow

2017 ◽  
Vol 14 (130) ◽  
pp. 20170185 ◽  
Author(s):  
Mahsa Dabagh ◽  
Payman Jalali ◽  
Peter J. Butler ◽  
Amanda Randles ◽  
John M. Tarbell
Keyword(s):  
Endothelial Cells ◽  
Inflammatory Responses ◽  
Flow Direction ◽  
Viscoelastic Model ◽  
Three Dimensional ◽  
Axial Flow ◽  
Focal Adhesions ◽  
Cortical Layer ◽  
Directional Flow ◽  
Unidirectional Flow

Local haemodynamics are linked to the non-uniform distribution of atherosclerosic lesions in arteries. Low and oscillatory (reversing in the axial flow direction) wall shear stress (WSS) induce inflammatory responses in endothelial cells (ECs) mediating disease localization. The objective of this study is to investigate computationally how the flow direction (reflected in WSS variation on the EC surface over time) influences the forces experienced by structural components of ECs that are believed to play important roles in mechanotransduction. A three-dimensional, multi-scale, multi-component, viscoelastic model of focally adhered ECs is developed, in which oscillatory WSS (reversing or non-reversing) parallel to the principal flow direction, or multi-directional oscillatory WSS with reversing axial and transverse components are applied over the EC surface. The computational model includes the glycocalyx layer, actin cortical layer, nucleus, cytoskeleton, focal adhesions (FAs), stress fibres and adherens junctions (ADJs). We show the distinct effects of atherogenic flow profiles (reversing unidirectional flow and reversing multi-directional flow) on subcellular structures relative to non-atherogenic flow (non-reversing flow). Reversing flow lowers stresses and strains due to viscoelastic effects, and multi-directional flow alters stress on the ADJs perpendicular to the axial flow direction. The simulations predict forces on integrins, ADJ filaments and other substructures in the range that activate mechanotransduction.

Three-Dimensional Viscoelastic Interactions of a Center of Dilatation with a Penny-Shaped Interfacial Crack

2011 ◽  
Vol 117-119 ◽  
pp. 471-475 ◽  
Author(s):  
Yu Zhou Sun ◽  
Ya Dong Bian ◽  
Zhong Guo Zhang
Keyword(s):  
Rock Fracture ◽  
Auxiliary Problem ◽  
Viscoelastic Model ◽  
Three Dimensional ◽  
Interfacial Crack ◽  
Viscoelastic Behavior ◽  
Inverse Laplace Transform ◽  
Bimaterial Interface ◽  
Thermal Dilatation ◽  
The Time Domain

This paper presents a three-dimensional viscoelastic model to study the interactions of a penny-shaped interfacial crack and a center of dilatation in the infinite viscoelastic bimaterial, which can model the rock fracture subjected to stress and thermal dilatation during some engineering process. A distinct issue associated with the present work is the incorporation of viscoelastic behavior of bimaterial. The proposed problem is first transformed into the Laplace space, and the solution in the transform space is obtained by decomposing the original problem into two auxiliary problems: (I) a center of dilatation near a bimaterial interface (no crack); and (II) a penny-shaped interfacial crack subject to internal tractions that cancel out those induced in auxiliary problem (I). The mode I, II and III stress intensity factors (SIFs) in the time domain are obtained with the inverse Laplace transform.

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