Interactive Simulation Method Research Articles

Interactive reproduction of virtual acoustic environments for the evaluation of hearing devices—Methods and validation

Virtual acoustic environments are increasingly used for evaluating hearing devices in complex acoustic conditions. In this talk we propose an interactive simulation method via multi-channel loudspeaker systems or headphones. The method focuses on the time-domain simulation of the direct path and a geometric image source model, which simulates air absorption and in case of motion the Doppler effect of all primary and image sources. To establish the feasibility of this approach, the interaction between reproduction method and technical and perceptual hearing aid performance measures was investigated using computer simulations. Three spatial audio reproduction methods were compared in regular circular loudspeaker arrays with 4 to 72 channels. The influence of reproduction method and array size on performance measures of multi-microphone hearing aid algorithms was analyzed. In addition to the analysis of reproduction methods, algorithm performance was tested in a number of different virtual acoustic environments in order to assess the underlying factors of decreased hearing aid performance in complex environments. The results confirm previous findings that spatial complexity has a major impact on hearing aid benefit, and demonstrate the potential of virtual acoustic environments for hearing aid evaluation. [Funded by DFG FOR1732 “Individualized hearing acoustics.”]

The application of interactive dynamic virtual surgical simulation visualization method

In this paper, an interactive dynamic simulation method is proposed to solve computational models of soft tissue undergoing large deformation, collision detection, and volume conservation in medical surgical simulation visualization. During the process of implementation of the interactive dynamic simulation method, the point-based method is used to simulate the elastic solids undergoing large deformations and the position-based method is used to simulate the objects collision, friction and volume conservation. Numerical results demonstrate that the proposed method improves the efficiency and stability of the response of heterogeneous soft tissue undergoing contact or even the multi-organs interactions, and it can be extended to interactive biopsy and cutting simulation.

Integrated simulation method for interaction between manufacturing process and machine tool

The interaction between the machining process and the machine tool (IMPMT) plays an important role on high precision components manufacturing. However, most researches are focused on the machining process or the machine tool separately, and the interaction between them has been always overlooked. In this paper, a novel simplified method is proposed to realize the simulation of IMPMT by combining use the finite element method and state space method. In this method, the transfer function of the machine tool is built as a small state space. The small state space is obtained from the complicated finite element model of the whole machine tool. Furthermore, the control system of the machine tool is integrated with the transfer function of the machine tool to generate the cutting trajectory. Then, the tool tip response under the cutting force is used to predict the machined surface. Finally, a case study is carried out for a fly-cutting machining process, the dynamic response analysis of an ultra-precision fly-cutting machine tool and the machined surface verifies the effectiveness of this method. This research proposes a simplified method to study the IMPMT, the relationships between the machining process and the machine tool are established and the surface generation is obtained.

A novel simulation method for interaction of machining process and machine tool structure

The dynamic performance of the machine tool system plays an important role on the machining process. On the other hand, it is difficult to consider the machine tool’s dynamic performance in the previous cutting simulation method. In this paper, a novel simulation method for the interaction simulation between the machining process and machine tool structure is presented. The influence of the dynamic performance of machine tool structure on the machining process and the interaction between them are considered by simplifying the machine tool structure in a novel finite element cutting simulation model. This model is used for potassium dihydrogen phosphate (KDP) crystal machining simulation; the chip formation and the waviness prediction are realized, and the simulation results agree well with the experiments, which provide the evidence and accuracy of this presented method.

Adaptive Skinning for Interactive Hair-Solid Simulation.

Reduced hair models have proven successful for interactively simulating a full head of hair strands, building upon a fundamental assumption that only a small set of guide hairs are needed for explicit simulation, and the rest of the hair move coherently and thus can be interpolated using guide hairs. Unfortunately, hair-solid interactions is a pathological case for traditional reduced hair models, as the motion coherence between hair strands can be arbitrarily broken by interacting with solids. In this paper, we propose an adaptive hair skinning method for interactive hair simulation with hair-solid collisions. We precompute many eligible sets of guide hairs and the corresponding interpolation relationships that are represented using a compact strand-based hair skinning model. At runtime, we simulate only guide hairs; for interpolating every other hair, we adaptively choose its guide hairs, taking into account motion coherence and potential hair-solid collisions. Further, we introduce a two-way collision correction algorithm to allow sparsely sampled guide hairs to resolve collisions with solids that can have small geometric features. Our method enables interactive simulation of more than 150 K hair strands interacting with complex solid objects, using 400 guide hairs. We demonstrate the efficiency and robustness of the method with various hairstyles and user-controlled arbitrary hair-solid interactions.

Suppressing flow-induced vibration of HGA by an acoustic PZT actuator in hard disk drives

The reliability and stability of hard disk drives (HDDs) is especially important as the areal recording density increasing rapidly target to 10 Tb/in2 in the future. The vibration of the Head Gimbals Assembly (HGA) is inevitable by internal fluid flow during operational process. In order to improve this undesirable problem, an acoustic piezoelectric transducer (PZT) actuator which can be used to transform an electric current to an acoustic pressure field, is glued on the HDD cover inner surface to generate acoustic pressure to suppress the flow-induced off-plate vibration (FIOPV) of the HGA. In this paper, a three-dimensional finite element model of HDD is built with an acoustic PZT actuator. The FIOPV of the HGA in the air and helium-filled drives are investigated by fluid---structure interaction simulation method. The acoustic pressure induced vibration (APIV) of the HGA is analyzed by acoustics-piezoelectric-structure interaction simulation method. After that, the suppressed FIOPV after superposing the APIV and the FIOPV is obtained by following the superposition principle.

An axial skeleton based surface deformation algorithm for patient specific anatomic modeling.

Traditionally, finite element analysis or mass-spring systems are used to calculate deformations of geometric surfaces. Patient-specific geometric models can be comprised of tens of thousands, even hundreds of thousands of polygons, making finite element analysis and mass-spring systems computationally demanding. Simulations using deformable patient specific models at real time rates are prohibitive under such a computational burden. This paper presents a method for simulating deformable surfaces by deforming a skeletal representation of the surface, rather than the surface itself, yielding an efficient method for interactive simulation with models.

Optimization of aerodynamic efficiency for twist morphing MAV wing

Twist morphing (TM) is a practical control technique in micro air vehicle (MAV) flight. However, TM wing has a lower aerodynamic efficiency (CL/CD) compared to membrane and rigid wing. This is due to massive drag penalty created on TM wing, which had overwhelmed the successive increase in its lift generation. Therefore, further CL/CDmax optimization on TM wing is needed to obtain the optimal condition for the morphing wing configuration. In this paper, two-way fluid–structure interaction (FSI) simulation and wind tunnel testing method are used to solve and study the basic wing aerodynamic performance over (non-optimal) TM, membrane and rigid wings. Then, a multifidelity data metamodel based design optimization (MBDO) process is adopted based on the Ansys-DesignXplorer frameworks. In the adaptive MBDO process, Kriging metamodel is used to construct the final multifidelity CL/CD responses by utilizing 23 multi-fidelity sample points from the FSI simulation and experimental data. The optimization results show that the optimal TM wing configuration is able to produce better CL/CDmax magnitude by at least 2% than the non-optimal TM wings. The flow structure formation reveals that low TV strength on the optimal TM wing induces low CD generation which in turn improves its overall CL/CDmax performance.

Solving problems of using some nonparametric goodness-of-fit tests

Estimates are given of the power of the Kuiper and Watson goodness-of-fit tests and three Zhang tests with the ZA, ZC, and ZK statistics with respect to some pairs of competing laws in testing simple and composite hypotheses. The powers of these tests are compared with the powers of the Kolmogorov, Cramer-von Mises-Smirnov, and Anderson-Darling tests. Statistic distribution models and tables of percentage points are constructed which allow the Kuiper and Watson goodness-of-fit tests to be used to test composite hypotheses about the goodness of fit of samples against various parametric distribution laws. An interactive simulation method is proposed that allows constructing and using distributions of test statistics in solving problems of statistical analysis.

Numerical Simulation Method for Fluid-Structure Interaction in Compressor Blades

A simulation method for fluid-structure interaction (FSI) in compressor blades was discussed to predict the aeroelastic stability of blades. Using the MFX, which is a Multi-Field Solver in ANSYS, the total force of computational fluid dynamics (CFD) have been interpolated to computational structural dynamics (CSD) grids, and then the vibration displacements of CSD nodes have been interpolated to CFD grids at the blade surface. In CFD analysis, the grid coordinates of the moveable region have been updated by multi-layer moving grid technique, and the finite volume method has been applied to calculate the Reynolds-averaged Navier-Stokes (RANS) equations closed by k-E turbulent model. For NASA Rotor 67, detect the displacement response of compressor blades at the design speed , and the aeroelastic stability of blades has been analyzed preliminarily. The study shows that the FSI procedure is feasible to predict the aeroelastic stability of compressor blades.

302 ナトリウム冷却高速炉の高温側1次主冷却系統合解析モデルの整備(OS3-(1),OS3 オーガナイズドセッション《熱・流体・エネルギー変換工学の進展》)

Numerical simulation method to analyze unsteady thermal-hydraulic phenomena in the upper plenum and the hot-leg piping system in Japan Sodium cooled Fast Reactor (JSFR) was developed in the previous studies. Since flow-induced vibration (FIV) in the hot-leg piping with the short elbow (curvature radius corresponds to diameter) is one of the targeted issues in this study, numerical estimation method for dynamic analysis of mechanical stress on piping has been developed successively. As the preliminary step in development of the fluid-structure mechanical interaction simulation method, time history response analysis of piping by using the time history data of fluid pressure obtained by the unsteady hydraulics simulation as its boundary condition was attempted. Through the numerical results, potential capability of the dynamic analysis of piping were confirmed and unsteady behavior of pipe due to the unsteady flow phenomena was analyzed.

Application of Nonparametric Kuiper and Watson Tests of Goodness-of-Fit for Composite Hypotheses

This is an examination of models of statistical distributions and tables of percentage points for application of the Kuiper and Watson tests of goodness-of-fit for composite hypotheses belonging to samples with different parametric models of their probability distributions. An interactive simulation method is presented which can be used for the construction and use of a statistical distribution of a test in the course of the statistical analysis associated with hypothesis testing.

Coupling Function and Mechanism of the Bionic Coupling Functional Surface (BCFS) Caused by the Dual Factors of Form and Flexible Material

Some living creatures have special structures on their body surfaces, such as smooth and elastic epidermis with subcutaneous tissue having non-smooth structures under certain conditions. The elastic epidermis coupled with non-smooth structures has a special function called bio-coupling functional surface. Imitating this functional surface and applying it in engineering has a potential to solve some engineering problems. Based on the simulation method of fluid-structure interaction (FSI), simulation calculation of the bionic functional surface coupled by the two factors, form and flexible materials was conduct using ADINA software. A viscous and weakly compressible transient flow was selected as a working medium, a discrete solver was selected in numerical calculation and the basic model was chosen as a turbulence model. It is assumed that the coupling surface of the form/flexible materials results is large deformation and large strain. The boundary condition of fluid-structure interaction was set as the calculation surface. The simulation results showed that this coupling is a dynamic process, in which the two factors (form and flexible materials) are influenced by the flow field. As the pressure and velocity of the flow field increase, the coupling process changes from partial coupling to complete coupling, the pressure drag decreased due to the maximum effective stress of bionic coupling surface is very small and the smooth and flexible materials can redistribute pressure by absorbing and releasing energy, the pressure drag thus formed is decreased. Moreover, non-smooth structures (form factor) coupled with flexible materials reduced velocity of working face and minimise energy losses effectively, enabling the bionic coupling surface to reduce drag.

Visual Modeling Application in the Aircraft Emergency Evacuation Simulation Based on Virtools

Using interactive virtual simulation methods and combining numerical calculation software, the 3D airline emergency evacuation simulation system is established in Virtools platform according to the received data. The system takes full account of the passengers' individual differences during the evacuation process, setting up different member parameters, which influence the passengers evacuation behavior. In order to fulfill the different types of evacuation requirements in various simulation, it can change evacuation path algorithm, cabin layout data and evacuees component parameters, to get the corresponding evacuation simulation results. Meanwhile, the system interface can change visual angle to realize human-machine interaction freely and reflect the evacuation of the evacuation process accurately. Also the reliability of the system simulation result is verified by compared with the results of actual certification trial.

Numerical simulation of parachute Fluid-Structure Interaction in terminal descent

A numerical simulation method for parachute Fluid-Structure Interaction (FSI) problem using Semi-Implicit Method for Pressure-Linked Equations (SIMPLE) algorithm is proposed. This method could be used in both coupling computation of parachute FSI and flow field analysis. Both flat circular parachute and conical parachute are modeled and simulated by this new method. Flow field characteristics at various angles of attack are further simulated for the conical parachute model. Comparison with the space-time FSI technique shows that this method also provides similar and reasonable results.

A fast wave-based hybrid method for interactive acoustic simulation in large and complex environments

Modern acoustic applications require fast and accurate simulation in large and complex environments. Current methods are rather limited to very simple environments or not able to perform fast interactive simulations. Our objective is to develop an innovative and practical method to perform real-time or near real-time accurate interactive simulation in large and complex environments, such as urban environments up to one kilometer. A new method, the embedded hybrid method using immersed boundary within k-space PSTD has been proposed and developed to achieve the objective. Its performance, accuracy, parallel hardware acceleration, and capabilities to handle all kinds of environmental complexities have been rigorously validated and verified by a number of examples. It shows that with the utilization of modern many-core GPUs, the method can perform real-time or near real-time accurate interactive simulation in large environments of hundreds to thousands of meters with all kinds of complexities including (1) inhomogeneous and absorptive medium, (2) curved and arbitrarily-shaped objects, (3) and moving sources, receivers, and objects, and time-varying medium.

Improved simulation method for soil-geogrid interaction of reinforced earth structure in FEM

The interaction between geogrid and soil is crucial for the stability of geogrid-reinforced earth structure. In finite element (FE) analysis, geogrids are usually assumed as beam or truss elements, and the interaction between geogrid and soil is considered as Coulomb friction resistance, which cannot reflect the true stress and displacement developed in the reinforcement. And the traditional Lagrangian elements used to simulate soil always become highly distorted and lose accuracy in high-stress blocks. An improved geogrid model that can produce shear resistance and passive resistance and a soil model using the Eulerian technique, in combination with the coupled Eulerian-Lagrangian (CEL) method, are used to analyze the interaction between geogrid and soil of reinforced foundation test in ABAQUS. The stress in the backfill, resistance of geogrid, and settlement of foundation were computed and the results of analysis agree well with the experimental results. This simulation method is of referential value for FE analysis of reinforced earth structure.

Real‐time fur simulation and rendering

AbstractReal‐time simulation of fur is a key element in many virtual reality applications. However, it is still difficult to simulate effects of fur animation in real‐time. In this paper, we propose an interactive fur simulation method, to calculate effects of external forces, such as wind and gravity, and direct manipulation for real‐time interactive animation. The proposed method consists of two layered textures for rendering. The first texture represents volumes of fur, and the second texture covers and laps the edge of the first texture. Our approach unifies these two structures using a shared vertex array to enhance rendering performance. We modify the shared vertex array with external force simulations and render it into the graphics pipeline. The proposed method is applied to virtual fashion design and 3D story telling as an example. Copyright © 2010 John Wiley & Sons, Ltd.

Complex molecular assemblies at hand via interactive simulations

Studying complex molecular assemblies interactively is becoming an increasingly appealing approach to molecular modeling. Here we focus on interactive molecular dynamics (IMD) as a textbook example for interactive simulation methods. Such simulations can be useful in exploring and generating hypotheses about the structural and mechanical aspects of biomolecular interactions. For the first time, we carry out low-resolution coarse-grain IMD simulations. Such simplified modeling methods currently appear to be more suitable for interactive experiments and represent a well-balanced compromise between an important gain in computational speed versus a moderate loss in modeling accuracy compared to higher resolution all-atom simulations. This is particularly useful for initial exploration and hypothesis development for rare molecular interaction events. We evaluate which applications are currently feasible using molecular assemblies from 1900 to over 300,000 particles. Three biochemical systems are discussed: the guanylate kinase (GK) enzyme, the outer membrane protease T and the soluble N-ethylmaleimide-sensitive factor attachment protein receptors complex involved in membrane fusion. We induce large conformational changes, carry out interactive docking experiments, probe lipid-protein interactions and are able to sense the mechanical properties of a molecular model. Furthermore, such interactive simulations facilitate exploration of modeling parameters for method improvement. For the purpose of these simulations, we have developed a freely available software library called MDDriver. It uses the IMD protocol from NAMD and facilitates the implementation and application of interactive simulations. With MDDriver it becomes very easy to render any particle-based molecular simulation engine interactive. Here we use its implementation in the Gromacs software as an example.

Effective simulation method for parametric signal-noise interaction in transmission fibers

We propose a new method for effective numerical simulation of transmission system performance and study of correlated noise evolution along an optical fiber with nonlinear parametric interaction between the amplified spontaneous emission (ASE) and the modulated optical signal. The method is based on an evaluation of the noise covariance matrix by using full nonlinear Schrödinger equation (NLSE) and an analytical model for the optical receiver. Using extensive brute-force Monte Carlo simulation as a verification tool, we test the accuracy of the method and illustrate the analytical receiver model limitations in the case of moderate as well as substantial growth of non-Gaussian optical noise along the optical fiber transmission link.