Snapping algorithm and heterogeneous bio-tissues modeling for medical surgical simulation and product prototyping

This paper presents a novel technique for modeling soft biological tissues as well as the development of an innovative interface for bio-manufacturing and medical applications. Heterogeneous deformable models may be used to represent the actual internal structures of deformable biological objects, which possess multiple components and non-uniform material properties. Both heterogeneous deformable object modeling and accurate haptic rendering can greatly enhance the realism and fidelity of virtual reality environments. In this paper, a tri-ray node snapping algorithm is proposed to generate a volumetric heterogeneous deformable model from a set of object interface surfaces between different materials. A constrained local static integration method is presented for simulating deformation and accurate force-feedback based on the material properties of a heterogeneous structure. Biological soft tissue modeling is used as an example to demonstrate the proposed techniques. By integrating the heterogeneous deformable model into a virtual environment, users can both observe different materials inside a deformable object as well as interact with it by touching the deformable object using a haptic device. The presented techniques can be used for surgical simulation, bio-product design, bio-manufacturing, and medical applications.     

Rapid prototyping: from product development to medicine and beyond

This paper discusses the current status of layer-based manufacturing rapid prototyping (RP) technology and how it is currently being implemented as a tool for product development (PD). A discussion on RP for PD is given, focusing on the limitations of existing technology. The paper then goes on to discuss the specific application field of medicine, explaining how this application may influence changes in the technology. Future trends for RP development are then discussed with further consideration for software issues in future applications and how the technology is being accepted worldwide.     

Rapid prototyping: from product development to medicine and beyond

This paper discusses the current status of layer-based manufacturing rapid prototyping (RP) technology and how it is currently being implemented as a tool for product development (PD). A discussion on RP for PD is given, focusing on the limitations of existing technology. The paper then goes on to discuss the specific application field of medicine, explaining how this application may influence changes in the technology. Future trends for RP development are then discussed with further consideration for software issues in future applications and how the technology is being accepted worldwide.     

A framework of virtual prototyping environment for the design and analysis of mechanical mechanism with clearance

Mechanical mechanisms with clearance abound in technological fields such as robotics, machine and steam turbine industry. The dynamic performance of these mechanisms in working condition can be achieved provided that the effects of the different on the mechanisms (such as mechanism dynamics, technological effects and thermal behaviour) are thoroughly understood. Virtual prototyping provides an integration of multi-domain dynamic simulation for the design and analysis process. In the current paper, a framework of virtual prototyping environment for the design and analysis of mechanical mechanism with clearance is presented. A case study with such a simulation strategy is studied for the optimum design and analysis of the technological parameter.     

A framework of virtual prototyping environment for the design and analysis of mechanical mechanism with clearance

Mechanical mechanisms with clearance abound in technological fields such as robotics, machine and steam turbine industry. The dynamic performance of these mechanisms in working condition can be achieved provided that the effects of the different on the mechanisms (such as mechanism dynamics, technological effects and thermal behaviour) are thoroughly understood. Virtual prototyping provides an integration of multi-domain dynamic simulation for the design and analysis process. In the current paper, a framework of virtual prototyping environment for the design and analysis of mechanical mechanism with clearance is presented. A case study with such a simulation strategy is studied for the optimum design and analysis of the technological parameter.     

Industrial application of RAM modeling: Development and implementation of a RAM simulation model for the Lexan plant at GE Industrial, Plastics

A RAM (reliability, availability and maintenance) model has been built for the GE Industrial, Plastics Lexan^® plant in Bergen op Zoom, The Netherlands. It was based on a Reliability Block Diagram with a Monte Carlo simulation engine. The model has been validated against actual plant data from two different sources, and against local expert opinions, resulting in a satisfactory simulation model. The model was used to assess two key decisions that were (to be) made by GE Industrial, Plastics concerning operation and shutdown policies of the plant. The model results showed that the operation and maintenance could be further improved, and that in doing so the annual production loss could be reduced further.     

面向排爆机器人的虚拟仿真训练系统设计与实现

针对排爆机器人使用和训练的需求,设计并实现了一套排爆机器人虚拟仿真训练系统.首先分析了排爆机器人的常见结构,针对一种通用结构设计的排爆机器人设计了仿真训练系统的结构,并对仿真系统的几何建模、运动模型和碰撞检测进行了分析,最后实现了排爆机器人虚拟仿真训练系统.该系统使操作手能够熟悉并掌握排爆机器人的操作.     

Materials integrity in microsystems: a framework for a petascale predictive-science-based multiscale modeling and simulation system

Microsystems have become an integral part of our lives and can be found in homeland security, medical science, aerospace applications and beyond. Many critical microsystem applications are in harsh environments, in which long-term reliability needs to be guaranteed and repair is not feasible. For example, gyroscope microsystems on satellites need to function for over 20 years under severe radiation, thermal cycling, and shock loading. Hence a predictive-science-based, verified and validated computational models and algorithms to predict the performance and materials integrity of microsystems in these situations is needed. Confidence in these predictions is improved by quantifying uncertainties and approximation errors. With no full system testing and limited sub-system testings, petascale computing is certainly necessary to span both time and space scales and to reduce the uncertainty in the prediction of long-term reliability. This paper presents the necessary steps to develop predictive-science-based multiscale modeling and simulation system. The development of this system will be focused on the prediction of the long-term performance of a gyroscope microsystem. The environmental effects to be considered include radiation, thermo-mechanical cycling and shock. Since there will be many material performance issues, attention is restricted to creep resulting from thermal aging and radiation-enhanced mass diffusion, material instability due to radiation and thermo-mechanical cycling and damage and fracture due to shock. To meet these challenges, we aim to develop an integrated multiscale software analysis system that spans the length scales from the atomistic scale to the scale of the device. The proposed software system will include molecular mechanics, phase field evolution, micromechanics and continuum mechanics software, and the state-of-the-art model identification strategies where atomistic properties are calibrated by quantum calculations. We aim to predict the long-term (in excess of 20 years) integrity of the resonator, electrode base, multilayer metallic bonding pads, and vacuum seals in a prescribed mission. Although multiscale simulations are efficient in the sense that they focus the most computationally intensive models and methods on only the portions of the space–time domain needed, the execution of the multiscale simulations associated with evaluating materials and device integrity for aerospace microsystems will require the application of petascale computing. A component-based software strategy will be used in the development of our massively parallel multiscale simulation system. This approach will allow us to take full advantage of existing single scale modeling components. An extensive, pervasive thrust in the software system development is verification, validation, and uncertainty quantification (UQ). Each component and the integrated software system need to be carefully verified. An UQ methodology that determines the quality of predictive information available from experimental measurements and packages the information in a form suitable for UQ at various scales needs to be developed. Experiments to validate the model at the nanoscale, microscale, and macroscale are proposed. The development of a petascale predictive-science-based multiscale modeling and simulation system will advance the field of predictive multiscale science so that it can be used to reliably analyze problems of unprecedented complexity, where limited testing resources can be adequately replaced by petascale computational power, advanced verification, validation, and UQ methodologies.     

EPS控制器建模与动态性能试验仿真

电动助力转向(electric power steering,EPS)控制器动态性能直接影响EPS总成的快速响应性和平稳性.利用Matlab/Si mulink创建EPS控制器模型,设计了EPS基本助力特性和包含PID算法、电流反馈的控制策略;利用AMESi m创建EPS负载模型并组装系统仿真模型,定义软件的数据交换接口并进行联合仿真.通过仿真,研究了三种标准激励下控制器动态性能的评价方法,讨论了助力电机关键参数对控制器性能的影响.结果表明,依托特定负载建模构建半物理仿真系统,进行脱离EPS总成环境的控制器动态性能试验是可行的.     

Polysilicon high frequency devices for large area electronics: Characterization, simulation and modeling

Laser Crystallised Polysilicon Thin Film Transistors have now sufficient good conduction properties to be used in high-frequency applications. In this work, we report the results for 5 μm long polysilicon TFTs obtained at frequencies up to several hundred MHz for applications such as RFID tags or System-On-Panel. In order to investigate the device operation, DC and AC two-dimensional simulations of these devices in the Effective Medium framework have been performed. In the light of simulation results, the effects of carrier trapping and carrier transit on the device capacitances as a function of dimensions are analysed and compared. An equivalent small-signal circuit which accounts for the behaviour of these transistors in all regions of operation is proposed and a model for the most relevant elements of this circuit is presented. To validate our simulation results, scattering-parameters (S-parameters) measurements are performed for several structures such as multi-finger, serpentine and linear architectures and the most meaningful parameters will be given. Cut-off frequencies as high as 300 MHz and maximum oscillation frequencies of about 600 MHz have been extracted.     

神经元PID在空调机组性能试验室温度控制中的建模与仿真

针对焓差法空调机性能试验室环境控制中被控对象具有大滞后、慢时变、非线性及不确定干扰因素多等特点，将具有自学习、自适应功能的神经元PID控制器应用于温度控制系统中，通过数学建模并在MATLAB环境下的计算机仿真，证明了神经元PID控制的实用性和有效性。     

Modeling and simulation of curing kinetics for the cardanol-based vinyl ester resin by means of non-isothermal DSC measurements

The cure kinetics of vinyl ester-styrene system was studied by non-isothermal differential scanning calorimetric (DSC) technique at four different heating rates. The kinetic parameters of the curing process were determined by isoconversional method for the kinetic analysis of the data obtained by the thermal treatment. Activation energy (E_a = 56.63 kJ mol⁻¹) was evaluated for the cure process and a two-parameter (m, n) autocatalytic model was found to be the most adequate to describe the cure kinetics of the studied cardanol-based vinyl ester resin. Non-isothermal DSC curves, as obtained by using the experimental data, show good agreement with the DSC curves obtained by theoretically calculated data.