Papers by Keyword: Fluid Structure Interaction (FSI)

Abstract: High-strength steel pipes have excellent strength but have poor fracture arrest. By finite-element analysis involving fluid-structure interaction (FSI) method, models of high-strength steel pipe with three kinds of defects (triangle, rectangle and semi-ellipse) were built to determine the concentrated stress based on the working conditions of X70 pipelines in the West-to-East Natural Gas Transmission Project, and the simulation results were compared with the field test results measured by an X-ray stress analyzer. With the same defect width (2 mm), the triangular defect (40°) had a greater influence on the concentrated stress in the pipe than rectangular and semi-elliptic defects. The results can be taken as references of the damage failure process of the defect in pipes in operating conditions as well as a theoretical basis for the fracture arrest of pipes in field operation.

Abstract: Twist Morphing (TM) wing is one of biomimetic MAV design that highly depends on morphing force actuation. Despite of vital morphing force influenced, the effect of morphing force variation on the aerodynamic performances of TM wing was not fully comprehended due to high complexity of fluid-structure interaction (FSI) behaviour. To elucidate the effect of morphing force influence, a series of TM wing with different morphing force intensity was used here to elucidate the effect of morphing force on C_L, C_D, and C_M distribution. Fully coupled Ansys-FSI method was employed in this study. C_L and C_M results showed that TM wing with higher morphing force configuration had induced better static stability and higher C_L distribution. However, TM wing also promoted earlier AOA_stall incidence and higher C_D penalty than the baseline wings. These situations turn out to be greater in the TM wing cases with higher morphing force configurations.

Abstract: In this study, we conducted water hammer experiments in the tube which was periodically supported by various numbers of clamps, named periodic structure, initiated by a projectile impact. The parts of the polycarbonate (PC) tube supported by 1-7 steel clamps make the tube stiffer and heavier than the original PC tube and are expected to cause a filtering effect of the frontal frequency components in the water hammer. According to our experimental observations, we confirmed that higher frequency components more than 1 kHz in the wave front were attenuated and the peak strains in circumferential direction of the tube were decreased 20% from the original PC tube. Moreover, we conducted numerical simulations of the water hammer wave similar to the experimental setup. Numerical results also revealed that frontal peak is attenuated 22% through periodic structure.

Abstract: Our study focuses on the response of a water-filled polycarbonate tube under axial impact loading to the presence of a single large suspended particle. The particles, composed of steel, aluminum, and polycarbonate, were individually suspended by elastic string along the centerline of the tube. The impact of a free-fall piston initiated pressure waves in the water, called water hammer, and stress waves in the tube, especially at the level of the particle. Hoop strains were measured as impact responses; their distribution indicated that the maximum strains occurred around the particle. These maximum strains are narrowly confined and independent of particle composition. From measurements, hoop strain above the level of the particle become larger with increasing particle mass. We propose a theoretical model that assumes the particle to be a rigid body, and estimate tube responses from the change in area due to the particle’s presence rather than a dependence on particle material. With similar conditions as in experiments, numerical simulations, performed using the software AUTODYN, revealed that the particle motion initiated a reflected pressure wave and created another pressure wave underneath the particle. The transients propagating around the particle are independent of particle material, but composition does affect the attenuation of the reflected pressure wave above the particle.

Abstract: The momentum transfer by a planar wave impinging upon a rigid, free-standing plate in water, a largely incompressible medium, is well understood [1]. Kambouchev et al. [2] extended the results of Taylor [1] to include the nonlinear effects of compressibility whilst Hutchinson [3] has recently addressed the issues of energy and momentum transfer to a rigid, free-standing plate. In this paper, key conclusions from the aforementioned studies are critically re-examined in the context of a `fully-clamped' elastic plate. The dynamic response of an elastic plate is represented by an equivalent single-degree-of-freedom (SDOF) system. A numerical method based on a Lagrangian formulation of the Euler equations of compressible flow and conventional shock-capturing techniques, similar to that employed in [2, 3], were employed to solve numerically the interaction between the air blast wave and elastic plate. Particular emphasis is placed on elucidating the energy and momentum transfer to a `fully-clamped' elastic plate compared to its rigid, free-standing counterpart, and on whether enhancement in the beneficial effects of FSI as a result of fluid compressibility remains and to what extent.

Abstract: A marine steam turbine control valve is taken as the research object in this paper, the vibration response is studied under pressure pulse excitation. The transient flow field analysis is made using the method of large eddy simulation to obtain the time-domain information of the pressure pulsation. Then, the analysis of vibration based on coupled modes, research vibration response and resonance problems of the control valve. The study found that the vibration of control valve is strongly in low frequency excitation, but high-frequency excitation makes relatively little impacts on it; The diffuser and downstream of valve is the main area of generating vibration.

Abstract: Liquid-Driven Stretch Blow Molding is a new and innovative method to produce PET bottles [. In the well-established Stretch Blow Molding (SBM) process, preforms are biaxially deformed by pressurized air into a cavity. The resulting bottles are transferred to a separate machine, where the desired product is filled in. In contrast to that, Liquid-Driven Stretch Blow Molding is characterized by employing the liquid product to deform the material. The former separated blowing and filling steps are thus combined to a single forming stage leading to numerous advantages in energy consumption, cycle time and machine footprint. In this paper, a numerical simulation of the new process is presented. An additional challenge compared to SBM simulations is thereby the consideration of the interaction between liquid and preform. The load application cannot be solely represented by the pressure because the influx behavior as well as gravity and inertia forces influence the preform deformation. A smoothed particle hydrodynamics (SPH) approach is applied to the simulation to incorporate the additional effects. The process model is evaluated by prototype experiments. In addition, a feasibility study shows the applicability of a rotary forming system to the new process.

Abstract: This paper further analyzes some existent problems of coupling vibration equations of water hammer, based on the improved continuity equation, it is derived simply for calculating coupled water hammer vibration, comparison with continuity equation that is to be used widely, the new continuity equation is basically consistent with commonly used continuity equations, so, the improved continuity equation can be used to calculate water hammer based on fluid-structure interaction (FSI).

Abstract: Designing light-weight high-performance materials which can sustain high impulsive loadings is of great interest to marine applications. In this study, a finite element fluid-structure interaction model is developed to understand the deformation and failure mechanisms of both monolithic and sandwich composite panels. Fiber (E-glass fiber) and matrix (vinylester resin) damage and degradation in individual unidirectional composite laminas are modeled with Hashin’s model. The delamination between laminas is modeled by developing a strain rate sensitive cohesive law. The deformation of the core (H250 PVC foam) in sandwich panels is modelled as a crushable foam plasticity model with volumetric hardening and strain rate sensitivity as well. The deformation history, fiber/matrix damage patterns in laminas, and inter-lamina delamination in both monolithic and sandwich composite panels are identified and compared with the experimental observations. The model suggests that the foam plays an important role in improving the performance of the sandwich panels by suppressing the transmitted impulsive acting on the back-sheets.

Abstract: This work presents a 3D computation of fluid-structure interaction in a cyclone separator. The finite volume method was used to simulate the flow field in the cyclone separator. The fluid-structure interaction was conducted by transferring the computational pressure distribution to the corresponding surface of the cyclone shell. The stress and deformation distribution in the cyclone shell was computed by the finite element method. Results obtained show that the maximum equivalent stress and deformation is linearly increases with the increases of the inlet gas velocity.