Anisotropic creep behavior of soft-hard interbedded rock masses based on 3D printing and digital imaging correlation technology

Three-dimensional(3D)printing technology is increasingly used in experimental research of geotechnical engineering.Compared to other materials,3D layer-by-layer printing specimens are extremely similar to the inherent properties of natural layered rock masses.In this paper,soft-hard interbedded rock masses with different dip angles were prepared based on 3D printing(3DP)sand core technology.Uniaxial compression creep tests were conducted to investigate its anisotropic creep behavior based on digital imaging correlation(DIC)technology.The results show that the anisotropic creep behavior of the 3DP soft-hard interbedded rock mass is mainly affected by the dip angles of the weak interlayer when the stress is at low levels.As the stress level increases,the effect of creep stress on its creep anisotropy increases significantly,and the dip angle is no longer the main factor.The minimum value of the long-term strength and creep failure strength always appears in the weak interlayer within 30°–60°,which explains why the failure of the layered rock mass is controlled by the weak interlayer and generally emerges at 45°.The tests results are verified by comparing with theoretical and other published studies.The feasibility of the 3DP soft-hard interbedded rock mass provides broad prospects and application values for 3DP technology in future experimental research.

Modeling Methods of 3D Model in Digital Twins

To understand the current application and development of 3D modeling in Digital Twins(DTs),abundant literatures on DTs and 3D modeling are investigated by means of literature review.The transition process from 3D modeling to DTs modeling is analyzed,as well as the current application of DTs modeling in various industries.The application of 3D DTs modeling in the􀀀elds of smartmanufacturing,smart ecology,smart transportation,and smart buildings in smart cities is analyzed in detail,and the current limitations are summarized.It is found that the 3D modeling technology in DTs has broad prospects for development and has a huge impact on all walks of life and even human lifestyles.At the same time,the development of DTs modeling relies on the development and support capabilities of mature technologies such as Big Data,Internet of Things,Cloud Computing,Articial Intelligence,and game technology.Therefore,although some results have been achieved,there are still limitations.This work aims to provide a good theoretical support for the further development of 3D DTs modeling.

Review of Digital Campus Construction Led by Virtual Reality Technology

In recent years,the government has issued a series of documents to promote the construction of digital campuses.This initiative serves to encourage the deep integration of information technology and intelligent technology education and digital reform,the combination of virtual reality and campus management is the need for innovative thinking and economic and social development,and then better change our learning style and living environment.The construction of the digital campus is based on virtual reality technology,BIM,GIS,and three-dimensional modeling technology to provide an immersive platform for students,promote the integration of virtual reality technology and education,help teachers,students,and parents to understand all kinds of education information and resources,to achieve their interoperability.From the off-campus environment to the school teaching equipment,teachers to teaching quality certification,and learning,to extracurricular entertainment,opening ceremonies to graduation parties,to bring more efficient,convenient,and safe campus life for teachers,students,and staff in school,and break the traditional information restrictions.

Reconstruction of 3-D digital cores using a hybrid method

A 3-D 数字核心描述岩石的毛孔空间微观结构。X 光检查微 CT 扫描是最精确、直接却昂贵的方法获得 3-D 数字核心。在这研究，我们建议联合沉积模拟的一个混合方法并且退火模仿(SA ) 产生 3-D 的方法数字核心基于岩石的 2-D 图象。有沉积模拟的方法开始造 3-D 数字核心，它是为 SA 方法的起始的配置。我们用 SA 方法更新起始的数字核心匹配 2-D 岩石图象的自相关功能并且最后造最后的 3-D 数字核心。与典型 SA 方法相比，混合方法显著地减少了计算时间。本地孔理论被用于份量上比较重建的 3-D 有 X 光检查微 CT 3-D 图象的数字核心。结果显示 3-D 数字核心由混合方法重建了有同质和 X 光检查微 CT 图象的类似于那些的几何连接。形成因素和重建的 3-D 的渗透数字核心用有限元素方法被估计(女性) 并且格子 Boltzmann 方法(LBM ) 分别地。模仿的结果在对试验性的大小的好同意。模拟结果的比较建议数字核心由更多仔细独自比典型 SA 方法反映真运输性质的混合方法重建了。

Uniaxial experimental study of the acoustic emission and deformation behavior of composite rock based on 3D digital image correlation(DIC)

In this paper, uniaxial compression tests were carried out on a series of composite rock specimens with different dip angles, which were made from two types of rock-like material with different strength. The acoustic emission technique was used to monitor the acoustic signal characteristics of composite rock specimens during the entire loading process. At the same time, an optical non-contact 3 D digital image correlation technique was used to study the evolution of axial strain field and the maximal strain field before and after the peak strength at different stress levels during the loading process. The effect of bedding plane inclination on the deformation and strength during uniaxial loading was analyzed. The methods of solving the elastic constants of hard and weak rock were described. The damage evolution process, deformation and failure mechanism, and failure mode during uniaxial loading were fully determined. The experimental results show that the θ = 0?–45?specimens had obvious plastic deformation during loading, and the brittleness of the θ = 60?–90?specimens gradually increased during the loading process. When the anisotropic angle θincreased from 0?to 90?, the peak strength, peak strain,and apparent elastic modulus all decreased initially and then increased. The failure mode of the composite rock specimen during uniaxial loading can be divided into three categories:tensile fracture across the discontinuities(θ = 0?–30?), slid-ing failure along the discontinuities(θ = 45?–75?), and tensile-split along the discontinuities(θ = 90?). The axial strain of the weak and hard rock layers in the composite rock specimen during the loading process was significantly different from that of the θ = 0?–45?specimens and was almost the same as that of the θ = 60?–90?specimens. As for the strain localization highlighted in the maximum principal strain field, the θ = 0?–30?specimens appeared in the rock matrix approximately parallel to the loading direction,while in the θ = 45?–90?specimens it appeared at the hard and weak rock layer interface.

Dynamic full-color digital holographic 3D display on single DMD

Digital holography has high potentials for future 3D imaging and display technology.We present a method for a dynamic full-color digital holographic 3D display on single digital micro-mirror device(DMD)with full-color,high-speed and high-fidelity characteristics.We combine the square regions of adjacent micro-mirrors into super-pixels that can modulate amplitude and phase independently.Gray images are achieved by amplitude modulation and precise positioning of each color is achieved by phase modulation.The proposed method realizes a full-color imaging based on the three primary colors and achieves measured structural similarity of more than 88%and color similarity of more than 98%,while retaining the high switch speed of 9 kHz,thus achieving dynamic full-color 3D display on charge-coupled device(CCD).

Effect of layer thickness on the flexural property and microstructure of 3D-printed rhomboid polymer-reinforced cemented tailing composites

For mines with poor ore bodies and surrounding rocks,the general mining method does not allow the ore to be extracted from underground safely and efficiently.For these mines,the downward layered filling mining technique is undoubtedly the most suitable mining method.The downward filling mining technique may eliminate the troubles relating to poor ore deposit conditions,such as production safety,ore loss rate,and depletion rate.However,in this technique,the safety of the artificial roof of the next stratum is of paramount importance.Cementitious tailings backfilling(CTB)that is not sufficiently cemented and causes collapses could threaten ore production.This paper explores a diamond-shaped composite structure to mimic the stability of a glued false roof in an actual infill mine based on the recently emerged three-dimensional(3D)printing technology.Experimental means such as three-point bending and digital image correlation(DIC)techniques were used to explore the flexural characteristics of 3D construction specimens and CTB combinations with different cement/tailings weight ratios at diverse layer heights.The results show that the 3D structure with a 14-mm ply height and CTB has strong flexural characteristics,with a maximum deflection value of 30.1 mm,while the 3D-printed rhomboid polymer(3D-PRP)structure with a 26-mm ply height is slightly worse in terms of flexural strength characteristics,but it has a higher maximum flexural strength of 2.83 MPa.A combination of 3D structure and CTB has more unique mechanical properties than CTB itself.This research work offers practical knowledge on the artificial roof performance of the downward layered filling mining technique and builds a scientific knowledge base regarding the successful application of CTB material in mines.

Multi-source data-based 3D digital preservation of large scale ancient chinese architecture:A case report

The 3D digitalization and documentation of ancient Chinese architecture is challenging because of architectural complexity and structural delicacy.To generate complete and detailed models of this architecture,it is better to acquire,process,and fuse multi-source data instead of single-source data.In this paper,we describe our work on 3D digital preservation of ancient Chinese architecture based on multi source data.We first briefly introduce two surveyed ancient Chinese temples,Foguang Temple and Nanchan Temple.Then,we report the data acquisition equipment we used and the multi-source data we acquired.Finally,we provide an overview of several applications we conducted based on the acquired data,including ground and aerial image fusion,image and LiDAR(light detection and ranging)data fusion,and architectural scene surface reconstruction and semantic modeling.We believe that it is necessary to involve multi-source data for the 3D digital preservation of ancient Chinese architecture,and that the work in this paper will serve as a heuristic guideline for the related research communities.

Reconstructing the 3D digital core with a fully convolutional neural network

In this paper, the complete process of constructing 3D digital core by fullconvolutional neural network is described carefully. A large number of sandstone computedtomography (CT) images are used as training input for a fully convolutional neural networkmodel. This model is used to reconstruct the three-dimensional (3D) digital core of Bereasandstone based on a small number of CT images. The Hamming distance together with theMinkowski functions for porosity, average volume specifi c surface area, average curvature,and connectivity of both the real core and the digital reconstruction are used to evaluate theaccuracy of the proposed method. The results show that the reconstruction achieved relativeerrors of 6.26%, 1.40%, 6.06%, and 4.91% for the four Minkowski functions and a Hammingdistance of 0.04479. This demonstrates that the proposed method can not only reconstructthe physical properties of real sandstone but can also restore the real characteristics of poredistribution in sandstone, is the ability to which is a new way to characterize the internalmicrostructure of rocks.

Application of 3D Digital Technology in Urban Design:A Case Study of Wuhan City

To achieve standardization and facilitation of urban design and 3D demonstration of construction program,and provide technological support for urban design and approval of construction program,this project integrates planning control elements,builds 3D urban design platform and explores functions of the platform on the basis of existing 3D information base.The platform will improve the efficiency of planning management department's controlling over urban spaces and buildings,further play the role of planning department in supporting the urban construction decision making,and also promote the overall city image and quality of urban spaces.

Digital Refocusing: All-in-Focus Image Rendering Based on Holoscopic 3D Camera

This paper presents an innovative method for digital refocusing of different point in space after capturing and also extracts all-in-focus image. The proposed method extracts all-in-focus image using Michelson contrast formula hence, it helps in calculating the coordinates of the 3D object location. With light field integral camera setup the scene to capture the objects precisely positioned in a measurable distance from the camera therefore, it helps in refocusing process to return the original location where the object is focused;else it will be blurred with less contrast. The highest contrast values at different points in space can return the focused points where the objects are initially positioned as a result;all-in-focus image can also be obtained. Detailed experiments are conducted to demonstrate the credibility of proposed method with results.

Research of Constructing 3D Digital River Based on ArcEngine and SketchUp

With the development of the 3D GIS and the digital basin, it is important for us to deal with the rivers from the 3D space. Compared to traditional forms of 2D GIS, the 3D GIS system brings better user experience for us. After introducing the current development status of the 3D digital river, the paper proposes a novel method for constructing 3D digital river system. It explores the methods in 3D digital river modeling by SketchUp, driving 3D scene by ArcScene and secondary developing by ArcGIS Engine. It discusses the specific issues of 3D river modeling with a river in Nanjing, and sums up a complete 3D modeling of operational process. Finally, that proves the feasibility of the method.

Dynamic Investigations on the Wear Behavior of a 3D Revolute Joint Considering Time-Varying Contact Stiffness: Simulation and Experiment

The existence of the relative radial and axial movements of a revolute joint’s journal and bearing is widely known.The three-dimensional(3D)revolute joint model considers relative radial and axial clearances;therefore,the freedoms of motion and contact scenarios are more realistic than those of the two-dimensional model.This paper proposes a wear model that integrates the modeling of a 3D revolute clearance joint and the contact force and wear depth calculations.Time-varying contact stiffness is first considered in the contact force model.Also,a cycle-update wear depth calculation strategy is presented.A digital image correlation(DIC)non-contact measurement and a cylindricity test are conducted.The measurement results are compared with the numerical simulation,and the proposed model’s correctness and the wear depth calculation strategy are verified.The results show that the wear amount distribution on the bearing’s inner surface is uneven in the axial and radial directions due to the journal’s stochastic oscillations.The maximum wear depth locates where at the bearing’s edges the motion direction of the follower shifts.These find-ings help to seek the revolute joints’wear-prone parts and enhance their durability and reliability through improved design.

Integrating Highly Spatial Satellite Image for 3D Buildings Modelling Using Geospatial Algorithms and Architecture Environment

The growing demand for current and precise geographic information that pertains to urban areas has given rise to a significant interest in digital surface models that exhibit a high level of detail. Traditional methods for creating digital surface models are insufficient to reflect the details of earth’s features. These models only represent three-dimensional objects in a single texture and fail to offer a realistic depiction of the real world. Furthermore, the need for current and precise geographic information regarding urban areas has been increasing significantly. This study proposes a new technique to address this problem, which involves integrating remote sensing, Geographic Information Systems (GIS), and Architecture Environment software environments to generate a detailed three-dimensional model. The processing of this study starts with: 1) Downloading high-resolution satellite imagery; 2) Collecting ground truth datasets from fieldwork; 3) Imaging nose removing; 4) Generating a Two-dimensional Model to create a digital surface model in GIS using the extracted building outlines; 5) Converting the model into multi-patch layers to construct a 3D model for each object separately. The results show that the 3D model obtained through this method is highly detailed and effective for various applications, including environmental studies, urban development, expansion planning, and shape understanding tasks.

Analysis of Remotely Sensed Imagery and Architecture Environment for Modelling 3D Detailed Buildings Using Geospatial Techniques

The use of three-dimensional maps is more effective than two-dimensional maps in representing the Earth’s surface. However, the traditional methods used to create digital surface models are not efficient for capturing the details of Earth’s features. This is because they represent only three-dimensional objects in a single texture and do not provide a realistic representation of the real world. Additionally, there is a growing demand for up-to-date and accurate geo-information, particularly in urban areas. To address this challenge, a new technique is proposed in this study that involves integrating remote sensing, Geographic Information System, and Architecture Environment software to generate a highly-detailed three-dimensional model. The method described in this study includes several steps such as acquiring high-resolution satellite imagery, gathering ground truth data, performing radiometric and geometric corrections during image preprocessing, producing a 2D map of the region of interest, constructing a digital surface model by extending the building outlines, and transforming the model into multi-patch layers to create a 3D model for each object individually. The research findings indicate that the digital surface model obtained with comprehensive information is suitable for different purposes, such as environmental research, urban development and expansion planning, and shape recognition tasks.

腹壁下动脉穿支皮瓣的3D可视化研究

目的为腹壁下动脉穿支皮瓣的设计与安全截取提供解剖学依据。方法 8具新鲜尸体,采用选择性颜料灌注、动脉造影及CT扫描与三维重建,重点观察腹壁下动脉肌皮穿支及其跨越正中线的有效吻合血管。然后,层次解剖观测腹前外侧壁外径≥0.5 mm的穿支,测量其管径及其走行、分支、分布情况并拍摄X线片。利用Photoshop与Scion Image软件分析穿支供血的趋向性及其供血面积。结果腹壁下动脉的出现率为100%,平均每侧发出(4.8±1.7)支肌皮穿支,直径(0.7±0.2)mm,单穿支供血面积为33cm2,单个穿支皮瓣大小为20cm×15cm。结论腹壁下动脉起源、行程及其穿支较恒定。双侧肌皮穿支间有丰富的、跨越正中线的真性吻合,具备截取跨越中线的横向跨区穿支皮瓣的解剖学基础,横向皮瓣面积可达20cm×42cm。

建筑3D打印数字建造技术研究应用综述

3D打印技术起源于20世纪80年代末,也称为"增材制造"或"快速原型"技术。21世纪以来,随着3D打印技术的引入,数字建造成为了建筑领域数字化发展的趋势。本文对国内外现有建筑3D打印技术相关研究及应用情况进行了分析,依据使用材料和打印工艺将目前主要建筑3D打印技术归纳为三类:基于混凝土分层喷挤叠加的增材建造方法、基于砂石粉末分层粘合叠加的增材建造方法和大型机械臂驱动的材料三维构造建造方法。文章对未来建筑3D打印的研究方向提出了若干展望,包括材料理论及新材料研发、机械设备及工艺改良、软硬件协同和智能化控制研究、3D打印构件及结构力学性能研究、技术适用性及工作模式研究、技术标准体系研究、社会经济效益评价研究等方面。

基于GTP修正的R3DGM建模与可视化方法

将广义三棱柱(GTP)的辅助几何要素———对角线———修正为四面体,解决了R3DGM(真三维地学模型)中数据组织与几何要素的不一致和空间操作中的几何裂缝问题.修正后的GTP模型集成了TIN,GTP和四面体模型的优点,构建算法简单且空间操作无缝.R3DGM过程分3步进行:①根据钻孔孔口数据点与断层露头约束,按约束Delaunay法则生成地表不规则三角网(CD-TIN);②按地学推理规则,将CD-TIN中三角形沿钻孔迹线向下扩展生成GTP;③根据最小顶点标识法,将GTP模型转换成四面体.介绍了基于GTP修正构建的三维数字地质模型的任意平面剖切、虚拟开挖、空间查询等可视化方法.并结合北京CBD地下三维集成建模与空间操作,展示了模型构模及空间操作效果.

3D数字工厂监控系统的设计与实现

针对传统工厂监控软件系统存在的对空间点难以准确定位以及界面不够直观等不足,采用虚拟现实技术,运用OGRE和VC++混合编程技术,设计3D数字工厂监控系统。该系统主要有实时监控、3D场景多视角漫游、场景实体精细碰撞检测及粒子声音特效等功能。试验结果表明,该系统具有较强的沉浸感,及能够快速对复杂分布的检查点定位等特点。

基于对象全景技术的病理大体标本数字化3D标本制作研究

分析医学病理大体标本的应用现状和存在的问题,研究用对象全景技术构建病理大体标本数字化3D模型。用高清相机360度拍摄处理后的病理大体标本图像,然后运用软件技术进行处理,实现标本的数字化3D互动展示。所构建的数字化病理标本比照片或三维建模进行数字化的效果好,更适合临床应用并支持网络在线浏览。