Dynamic simulation insights into friction weakening effect on rapid long-runout landslides:A case study of the Yigong landslide in the Tibetan Plateau,China

This study proposed a novel friction law dependent on velocity,displacement and normal stress for kinematic analysis of runout process of rapid landslides.The well-known Yigong landslide occurring in the Tibetan Plateau of China was employed as the case,and the derived dynamic friction formula was included into the numerical simulation based on Particle Flow Code.Results showed that the friction decreased quickly from 0.64(the peak)to 0.1(the stead value)during the 5s-period after the sliding initiation,which explained the behavior of rapid movement of the landslide.The monitored balls set at different sections of the mass showed similar variation characteritics regarding the velocity,namely evident increase at the initial phase of the movement,followed by a fluctuation phase and then a stopping one.The peak velocity was more than 100 m/s and most particles had low velocities at 300s after the landslide initiation.The spreading distance of the landslide was calculated at the two-dimension(profile)and three-dimension scale,respectively.Compared with the simulation result without considering friction weakening effect,our results indicated a max distance of about 10 km from the initial unstable position,which fit better with the actual situation.

Three-Dimensional and Cross-sectional Characteristics of Normal Grain Growth Based on Monte Carlo Simulation

An appropriate Monte Carlo method was developed to simulate the three-dimensional normal grain growth more completely. Comparative investigation on the three-dimensional and the cross-sectional characteristics of normal grain growth was done. It was found that the time exponent of grain growth determined from cross-section exhibits the same rule of increasing slowly with time and approaching the theoretical value n = 0.5 of steadygrain growth as the three-dimensional (3-D) system. From change of the number of grains per unit area with timemeasured in cross-section, the state of 3-D normal grain growth may be predicted. The gtain size distribution incross-section is different from that in 3-D system and can not express the evolution characteristic of the 3-D distribution. Furthermore, there exists statistical connection between the topological parameters in cross-section and thosein three-dimensions.

Sparsity-based efficient simulation of cluster targets electromagnetic scattering

An efficient and real-time simulation method is proposed for the dynamic electromagnetic characteristics of cluster targets to meet the requirements of engineering practical applications.First,the coordinate transformation method is used to establish a geometric model of the observation scene,which is described by the azimuth angles and elevation angles of the radar in the target reference frame and the attitude angles of the target in the radar reference frame.Then,an approach for dynamic electromagnetic scattering simulation is proposed.Finally,a fast-computing method based on sparsity in the time domain,space domain,and frequency domain is proposed.The method analyzes the sparsity-based dynamic scattering characteristic of the typical cluster targets.The error between the sparsity-based method and the benchmark is small,proving the effectiveness of the proposed method.

Modeling of Irregular Structures in Scene Simulation Based on Creator and 3dsmax

Creating proper 3D models plays an important pole in the development of scene simulation system based on multigen creator and Vega software. However, it is very difficult to construct complex structures by multigen creator. In this paper, an approach is proposed which is utilizing 3dsmax as assistant modeling software. 3D models developed in 3dsmax could be saved in 3ds format and then imported into multigen creator software. The models are revised and then saved in fit format by creator. For reducing model＇s data, simplification strategy is proposed. The problem of constructing complex models in creator is solved smoothly. In the development of digital rocket simulation project, the models constructed by this method have good visual effect, small size, and could be driven by Vega correctly.

Seabed scene simulation and its realization in extending Vega

Realistic simulation of underwater scene is always difficult because of the special and complex vision effects in underwater space. Seabed is an important part of underwater environment. This paper describes the methods for seabed scene simulation based on OpenGL. It includes construction of fluctuant terrain based on the random sinusoidal algorithm, simulation of seabed flicker effect by means of circular texture mapping and generation of turbidity effect by using fog techniques. For the application based on the leading high level 3D development environment-Vega, underwater scene simulation is still a difficulty since there is no module for it. Based on the analysis of Vega software and the research on seabed scene simulation methods, a Vega extending module named 'Underwater Space' was created through developing module class and extending lynx interface. The module class was designed through developing DLL written in C++. The Lynx was extended through developing keyword configure file, GUI configure file and lynx plug-in DLL. The problem that Vega can't simulate underwater space, is elementarily resolved. The results show that this module is efficient, easy using, and the seabed scene images are vivid.

Infrared image simulation of ground maneuver target and scene

Infrared scene simulation has extensive applications in military and civil fields. Based on a certain experimental environment,object-oriented graphics rendering engine（ OGRE） is utilized to simulate a real three-dimensional infrared complex scene. First,the target radiation of each part is calculated based on our experimental data. Then through the analysis of the radiation characteristics of targets and related material,an infrared texture library is established and the 3ds Max software is applied to establish an infrared radiation model.Finally,a real complex infrared scene is created by using the OGRE engine image rendering technology and graphic processing unit（ GPU） programmable pipeline technology. The results show that the simulation images are very similar to real images and are good supplements to real data.

Comparison of the Feasible Schemes for HT-7U Assembly Simulation

The whole superconducting HT-7U Tokamak is a high-cost and large-scale complicated device. The assembly requirement of HT-7U device is arduous and strict. At present, there have been no guiding principle for the assembly of the device, but assembly simulation can help the engineer plan and make decision by an intuitional and visual way before its actual assembly. The problem is that which scheme is most suitable should be solved primarily. From current research situation and technology progress of assembly simulation, this paper explained and analyzed four kinds of technological schemes of assembly simulation in common use. Finally, we got the most feasible scheme that was suitable for HT-7U assembly simulation by comparing their technological issues and difficult points of simulation among the four kinds of feasible schemes.

Development of driver-vehicle-road closed-loop semi-physical simulation system

As hybrid vehicles introduced the motor, the vehicle structure has a significant change in the power matching. A driver-vehicle-road closed-loop semi-physical simulation system, which makes real driving parts together with the simulation car, will bring convenience to the new car design. We used the computer software to simulate the road with a slope, curve and some other features based on the actual road condition, and analyzed the whole road scene in addition to geometry and physical characteristics. Analyzing and constructing the vehicle dynamics basic template, appropriate changes to the template can obtain the desired vehicle dynamics model with an external device to control the model vehicle. It combined the physical operation system with visual display, which gave us real driving feelings and increased the vehicle design predictive accuracy.

Computer-Aided Simulation of Mastoidectomy

Objective To establish a three-dimensional model of the temporal bone using CT scan images for study of temporal bone structures and simulation of mastoidectomy procedures. Methods CT scan images from 6 individuals (12 temporal bones) were used to reconstruct the Fallopian canal, internal auditory canal, cochlea, semicircular canals, sigmoid sinus, posterior fossa floor and jugular bulb on a computer platform. Their anatomical relations within the temporal bone were restored in the computed model. The same model was used to simulate mastoidectomy procedures. Results The reconstructed computer model provided accurate and clear three-dimensional images of temporal bone structures. Simulation of mastoidectomy using these images provided procedural experiences closely mimicking the real surgical procedure. Conclusion Computer-aided three dimensional reconstruction of temporal bone structures using CT scan images is a useful tool in surgical simulation and can aid surgical procedure planning.

典型光电系统的数字孪生技术

数字孪生技术将多学科多物理场的系统通过多维异构时序数据进行统一设计和管理,可构建高保真度的数字化镜像模型。本文基于此项技术,对典型光电系统的数字化模型提出了构建的思路和方法;同时结合场景要素本征物理特性分析,描述了高真实感红外场景数字孪生仿真的关键技术。数字模型和场景仿真的有机结合能够准确地实现光电系统的实时交互和迭代运行及优化,高效高质量地缩短产品的研制周期。

多分隔受限场景空间火灾疏散安全性分析

为了优化密室逃脱类场所的复杂空间布局,基于该场所剧情场景下空间多重分隔、空间狭小、封闭且组合多样等结构特点,分析归纳该场所3种典型的受限场景空间类型,以西安市某密室逃脱类场所建筑布局为例,运用Pathfinder和PyroSim软件对其展开火灾情景下的疏散模拟仿真,进而对比分析不同场景空间的火灾特性指标以及疏散安全性。研究结果表明:密室逃脱类场所3种场景空间中,串联式场景空间人员疏散时间最长(141.53 s),单元式次之(115.53 s),并联式最短(112.28 s);从火灾烟气模拟结果看,串联式场景空间安全出口的温度、CO体积分数以及能见度始终都处于安全临界范围内,而其他2种场景空间均超过临界值,并且能见度降至0.06 m,因此从安全性判定,该密室逃脱类场所只有串联式场景空间人员疏散过程是安全的,并联式和单元式场景空间人员疏散过程中均存在一定危险性。对于密室逃脱类场所这种特定狭小空间,烟气的危害对人员安全疏散的影响尤为显著,因此要在防排烟和火灾荷载方面进行重点防控。研究结果可为密室逃脱类场所的空间结构优化提供消防指导。

重大节假日出行方式选择模型研究

为优化节假日高速公路免费政策,选取出行者变量、出行方式相关变量和行程特性变量作为效用变量,构建了出行方式位于上层、出行距离位于下层的NL模型。利用弧弹性法分析不同收费标准和收费里程条件下出行者的行为特性,并利用场景仿真评价多种收费组合对出行方式的影响。研究结果表明:提高收费标准,汽车出行比例会显著降低,且高速铁路承担了大部分的转移交通量。随着收费里程的增加,出行者逐渐倾向于出行成本较小的普通铁路。对长距离出行收费可以提升公共交通分担率,缓解节假日高速公路的交通拥堵。

以问题为基础的学习联合场景模拟教学法对骨科护生参与度及综合能力的影响

目的探讨以问题为基础的学习(PBL)联合场景模拟教学法在骨科护生教学中的应用效果。方法选取2021年6月至2023年2月在我院骨科实习的88例护生为研究对象,将其随机分为传统教学组和联合教学组,各44例。传统教学组采用常规教学法,联合教学组采用PBL联合场景模拟教学法。比较两组的参与度、理论及实操成绩、批判性思维能力、教学评价及教师评价。结果联合教学组的教学、临床护理工作、沟通协作、科研、职业价值观、专业发展能力评分高于传统教学组(P<0.05)。第1、3、6个月,联合教学组的理论及实操成绩均高于传统教学组(P<0.05)。教学后,两组的批判性思维能力倾向量表(CTDI-CV)评分高于教学前,且联合教学组高于传统教学组(P<0.05)。联合教学组的教学好评率高于传统教学组(P<0.05)。联合教学组的教学质量、学生积极性、成绩反馈评分及总分高于传统教学组(P<0.05)。结论PBL联合场景模拟教学法能提升骨科护生的综合成绩,增强参与度,有助于提升护生的教学评价及带教老师的教师评价。

基于FMI的卫星数字仿真平台设计及实现

针对卫星仿真技术的标准化和通用化发展需求,基于FMI(functional mock-up interface)的接口标准和模型复用技术,构建一个能够支持卫星数字仿真的工具体系架构,在此基础上,运用模块化思想设计了卫星数字仿真平台,并给出Simulink及C/C++模型的FMI标准封装方法.利用卫星数字仿真平台,搭建了多星运行仿真场景,通过远程过程调用技术,将仿真过程数据推送到可视化平台中,完成对卫星运行场景的可视化展示.仿真案例说明,卫星仿真平台可以对模型运行状态及变化趋势进行监控,同时,场景可视化平台可以对卫星的运行轨道及姿态等数据实时动态显示.

基于三维场景的铁路车站列车运行联锁控制仿真研究

联锁控制对铁路车站的调度指挥和列车的有序安全运行起着非常关键的作用。为保证铁路车站联锁控制及列车运行演练的真实性和安全性,提出铁路车站联锁控制及列车运行三维虚拟仿真的总体框架。从铁路车站联锁功能入手,设计车站联锁控制的数据结构、功能逻辑和联锁控制仿真算法,实现了铁路车站联锁的逻辑控制及人机交互仿真。采用面向对象的层次分级法,设计铁路车站设备三维模型的层次结构。通过创建预制体并修改其组件的方式,构建铁路车站列车运行三维虚拟场景模型。结合铁路线路逻辑模型,提出了面向联锁控制的列车运行虚拟寻路算法和列车运动驱动算法,利用该算法进行列车各车辆空间位置和姿态的连续计算,实现了在三维场景下铁路列车的启动,加减速运动,定点停车、换道等功能。在此基础上,在Unity引擎环境下开发了基于三维场景的铁路车站列车运行联锁控制虚拟仿真系统,该系统支持铁路车站联锁控制人机交互仿真,并可在铁路车站三维场景中的不同视角下,以可视化方式观察信号设备状态变化以及列车的动态运行情况。通过给定的站内列车调度计划表,利用所开发的系统进行了铁路车站联锁控制及列车运行三维仿真。仿真实例表明,所采用的方法及技术方案在车站联锁的仿真演练与培训学习方面具有良好的应用前景和实际意义。

基于SIMULINK和VR技术的三维监视软件开发

在某武器系统演示试验中,需要对靶目标的运动进行实时跟踪,并方便直观地查看其飞行姿态和飞行轨迹。根据任务需求,给出了一种基于Matlab(Simulink)和VR技术的三维动态监视软件的实现方法。软件采用VB与Matlab混合编程,使用Simulink模型接收VB传送的数据并即时更新虚拟世界场景,充分利用虚拟现实技术的真实直观、视点可变、与现实同步等优点,很好地完成了动态监视任务。重点介绍了程序接口技术和Simulink模型控制技术,这种方法也能够方便地应用于其他类似的监视任务中。

基于PDCA的情景模拟教学在放射科中医住培学员中的应用探索

目的 探讨PDCA结合情景模拟教学在提高中医住培学员碘对比剂ADR处置能力中的应用效果。方法 将2020年9月-2021年5月在我科轮转的28名中医规培学员纳入对照组采用传统教学模式;将2021年6月-2022年2月在我科轮转的46名中医规培学员为试验组,采用PDCA+情景摸拟教学模式,试验组分为9个小组,每小组情景模拟教学中采用PDCA循环。将两组学员培训前、培训后的考核成绩,临床实践能力、学习兴趣、学习效率、团结协作能力和满意度纳入考核指标。结果 试验组和对照组培训后的考核成绩较培训前考核成绩均有显著提高(P<0.05);培训前的考核成绩两组间无统计学差异(P>0.05),培训后的考核成绩试验组高于对照组(P<0.05);在临床实践能力、学习兴趣、学习效率、团结协作能力和满意度方面试验组高于对照组(P<0.05)。结论 PDCA结合情景模拟教学方法有助于提高中医住培学员在碘对比剂ADR处置能力的教学效果,是一种值得推广的教学方法。

基于虚拟现实技术的船舶PSC检查训练仿真系统

针对现有PSCO培训效果差、风险和成本较高的问题,提出并开发了不受时间和场地限制的船舶PSC检查训练仿真系统。以集装箱船为例,运用三维建模技术构建船舶主要区域和仪器设备的模型,使用OCR文字识别技术实现证书文件的有效信息提取,运用反向动力学技术实现虚拟船员在三维场景中的操作模拟,运用模糊综合评判法建立PSC检查训练的评估模型,实现对学员检查过程的评估。仿真结果表明,所开发的系统场景沉浸感良好、满足PSC检查训练的需求,可用于PSCO的教学与培训。

基于AnyLogic的微观交通场景仿真研究

随着出行量增加,城市交通压力剧增,拥堵问题日益显著。如何分析交通拥堵因素,优化交通疏导方案,是一个很重要的问题。本文以郑州市二七广场附近交通为例,运用AnyLogic仿真技术进行全数据仿真建模研究,构建了车流量信息的数据统计模型。通过调整模型参数,进行了优化实验,结果表明:合理地优化调整红绿灯时长,可以使车辆在此路段的通行时间降低20%左右,能有效缓解交通拥堵。