A multi-purpose prototype test system for mechanical behavior of tunnel supporting structure: Development and application

A multi-purpose prototype test system is developed to study the mechanical behavior of tunnel sup-porting structure,including a modular counterforce device,a powerful loading equipment,an advanced intelligent management system and an efficient noncontact deformation measurement system.The functions of the prototype test system are adjustable size and shape of the modular counterforce structure,sufficient load reserve and accurate loading,multi-connection linkage intelligent management,and high-precision and continuously positioned noncontact deformation measurement.The modular counterforce structure is currently the largest in the world,with an outer diameter of 20.5 m,an inner diameter of 16.5 m and a height of 6 m.The case application proves that the prototype test system can reproduce the mechanical behavior of the tunnel lining during load-bearing,deformation and failure processes in detail.

Electromagnetic–thermal–structural coupling analysis of the ITER edge localized mode coil with flexible supports

In a fusion reactor, the edge localized mode（ELM） coil has a mitigating effect on the ELMs of the plasma. The coil is placed close to the plasma between the vacuum vessel and the blanket to reduce its design power and improve its mitigating ability. The coil works in a high-temperature,high-nuclear-heat and high-magnetic-field environment. Due to the existence of outer superconducting coils, the coil is subjected to an alternating electromagnetic force induced by its own alternating current and the outer magnetic field. The design goal for the ELM coil is to maintain its structural integrity in the multi-physical field. Taking as an example the middle ELM coil（with flexible supports） of ITER（the International Thermonuclear Fusion Reactor）, an electromagnetic–thermal–structural coupling analysis is carried out using ANSYS. The results show that the flexible supports help the three-layer casing meet the static and fatigue design requirements. The structural design of the middle ELM coil is reasonable and feasible. The work described in this paper provides the theoretical basis and method for ELM coil design.

Tunnel Support Structure System and Its Synergy

The tunnel support system is composed of lining,bolt,and steel frame.It is of great significance to effectively control the deformation of the surrounding rock of the tunnel,make full use of the characteristics of different support methods,and formulate an economical and effective support plan to ensure the safe operation of the tunnel structure.This paper clarifies the synergistic relationship between the support structure and the surrounding rock based on their fundamental characteristics and functions.Various support structures and components are also discussed in this paper.Additionally,the paper presents an optimized design of the tunnel support structure system.

Neuron-fibrous scaffold interfaces in the peripheral nervous system: a perspective on the structural requirements

The nerves of the peripheral nervous system are not able to effectively regenerate in cases of severe neural injury.This can result in debilitating consequences,including morbidity and lifelong impairments affecting the quality of the patient’s life.Recent findings in neural tissue engineering have opened promising avenues to apply fibrous tissue-engineered scaffolds to promote tissue regeneration and functional recovery.These scaffolds,known as neural scaffolds,are able to improve neural regeneration by playing two major roles,namely,by being a carrier for transplanted peripheral nervous system cells or biological cues and by providing structural support to direct growing nerve fibers towards the target area.However,successful implementation of scaffold-based therapeutic approaches calls for an appropriate design of the neural scaffold structure that is capable of up-and down-regulation of neuron-scaffold interactions in the extracellular matrix environment.This review discusses the main challenges that need to be addressed to develop and apply fibrous tissue-engineered scaffolds in clinical practice.It describes some promising solutions that,so far,have shown to promote neural cell adhesion and growth and a potential to repair peripheral nervous system injuries.

A Lower Rigid Support Structure for the HT-7U Vacuum Vessel

Vacuum vessel of the HT-7U is a fully welded toroidal structure with a noncircular cross-section nested in the bore of the TF coils. According to the requirement of the physics design, sixteen horizontal ports on outboard mid-plane and thirty-two vertical ports on the top and bottom are designed for diagnostics, plasma heating, current driving, vacuum pumping and gas puffing. Bellows on these port necks are used for flexible components to absorb the relative displacement in radial and vertical directions due to external load, thermal expansion or contrac-tion and assembly tolerance, and also used for isolation of mechanical vibration. For the support system of vacuum vessel it should be not only strong enough to withstand forces acting on the vessel interior components and the vessel itself due to the dead weight and electromagnetic inter-actions during plasma disruption, but also sufficiently flexible to be suited to thermal expansion during baking. In order to solve this contradiction a new kind of low rigid support has been designed, which has a perfectly rigid in vertical direction and perfectly soft in radial direction. Some three-dimension finite element COSMOS models were performed to analyze their structural strength, stiffness and fatigue life, with an emphasis on the static stress analysis. The load spectra during vacuum vessel operation were also simulated on these models in the view of fatigue design. It was confirmed that the bellows and support had sufficient strength in the designed range of the load conditions. The results showed that the peak stress on bellows was 87 MPa and on the support system was 97 MPa. Now all kinds of bellows and support system have been designed. In order to accumulate some engineering experiences and probe into some molding die and welding technologies, prototypical bellows and support system have been fabricated. At the same time a mechanical testing apparatus was designed for proof tests on the prototypical bellows and support to verify their functional and structure capability. The experimental data indicated that the re-sults of finite element analysis were coincident with experimental test results. It has been proved that the present vacuum vessel's bellows and support system are reasonable and feasible.

Investigation on the Fatigue Characteristic in Support Structure of HL-2M Tokamak

In order to obtain enhanced plasma parameters a complete new tokamak HL-2M is now under construction in Southwestern Institute of Physics. To assure the structural safety of the device for the entire operation cycle, one of the most important issues is the lifetime-limiting effects due to the pulsed operation mode. Fatigue is one of the major failure modes to be considered in mechanical design, and pulsed operation imposes stress with significant alternating components on the support structure （SS）. Therefore, the reliability of the whole device is strongly affected by the stress and fatigue characteristic of the SS as the interface structure. This article introduces the SS design and details the fatigue life calculation methods based on the different characteristics of the sub-structures. The fatigue life in hazardous areas of the toroidal field coils anti-torque structure （TFCs-ATs） has been determined by non-linear analysis results. And with the stress- time history data of the vacuum vessel ＆ poloidal field coils support structure （VV＆PFCs SS）, the fatigue analysis of the hot spots has been completed based on rain-flow counting method and linear cumulative damage method. The calculated minimum fatigue life on TFCs-ATs and VVSzPFCs SS is 4.743E＋05 and 1.805E＋06 cycles, respectively. And the calculated fatigue life on sub-structures can meet the required life for HL-2M tokamak： 1.0E＋05 cycles.

Information Monitoring Technology for Support Structure of Railway Tunnel During Operation

In the process of railway construction, because of the inconvenience ofgeological condition, water bursting and mud surging happen frequently, and the laterdeformation of support structure on the happening geology section would threaten thenormal running of railway. The limit difference of deformation control value of thesupport structure section where geological accidents frequently happen, is small, andartificial half-automatic supervisory technology cannot get the health condition of tunnelin time, resulting many cars speed-down accidents due to deformation of supportstructure. Through design innovation, we introduce TGMIS in the later period ofYanzishan railway construction to quickly capture the deformation of support structure,the strain of lining concrete, the strain of steel frame, stress of surrounding soil, stress ofsurrounding water, strain of second lining steel bar and other situ data. Also we setobservation prism and measuring robot device in specific position inside tunnel, androbot laser locator laser spot is projected onto reflection target surface, by graphicprocessing algorithm, the receiver calculates the measured value and standard value ofthe 3D coordinates of the laser spot. Then the information is transmitted throughtransmitting device, transducer and USB-485 to computer to predict and evaluate thehealth condition of the support structure of the tunnel so as to provide safety warninginformation. Provide timely and reliable data for the operation company to avoid theoccurrence of vicious accidents.

Synthesis, Characterization, and Properties of Supported Tungstozincate Bridged by Co(Ⅱ) Complex Fragment

[Co^11（phen）3]2[{（ZnW12O40）Co^11（phen）2（H2O）}2Co^11（trien）2（NaH2O）2]·3H2O was synthesized via hydrothermal technique and characterized with elemental analyses, IR spectroscopy, TGA-DTA, and variable temperature magnetic susceptibility. The compound crystallized in the monoclinic system with the space group P21/n, a=1.8210 nm, b=2.3592 nm, c=2.2932 nm, β=110.31°, V=9.239 nm^3, Z=2, R1=0.0827. The compound consists of two coordination cations, three lattice water molecules, and a macroanion [{（ZnW12O40）Co（phen）2（H2O）}2Co（C6H18N4）2·（NaH2O）2]^4- in which each supported Keggin anion [（ZnW12O40Co^11（phen）2（H2O）]^4- acts as a ligand to coordinate to central bridging Co^2＋ ion via a terminal oxygen atom. Hydrogen bonds are responsible for the construction of 3D architecture of the compound. The compound is paramagnetic with a weak antiferromagnetic interaction（0=-46.796 K）.

REQUIREMENTS AND DESIGN METHOD FOR MATCHING AIRCRAFT GUNS WITH THEIR SUPPORTING STRUCTURE

In aircraft structural dynamic design the matching of guns with their supportingstructure is one of the most important tasks on which hinges the success or failure of thestructural design.The design curves for matching guns with their supporting structure can be obtained fromresponse calculations of the plate-spring system supporting the gun on the ground,the modelstructure tested on the ground and the actual structure.A set of matching curves is given forengineering application.Then,the matching design can be accomplished by means of impactload spectrograms so as to perform an optimal structural design and to make further improvementson dynamic design program.

Recent developments in the structural design and optimization of ITER neutral beam manifold

This paper describes a new design of the neutral beam manifold based on a more optimized support system.A proposed alternative scheme has presented to replace the former complex manifold supports and internal pipe supports in the final design phase.Both the structural reliability and feasibility were confirmed with detailed analyses.Comparative analyses between two typical types of manifold support scheme were performed.All relevant results of mechanical analyses for typical operation scenarios and fault conditions are presented.Future optimization activities are described,which will give useful information for a refined setting of components in the next phase.

Research on Temperature Field of the Support Structure for the Independent LNG Tank

The independent LNG(Liquified Nature Gas)containment is widely used for small or medium-sized LNG carrier and ship using LNG as fuels.The common tank pattern includes single-spherical-cylindrical tank and double-spherical-cylindrical tank,which is the key to design the hull structure and its support.The support is designed to connect the hull structure and LNG tank.Its main functions are heat transferring and force loading.This paper focus on the temperature field distribution of hull and its support structure.The thermal boundary conditions are simulated according to the heat transfer action,such as thermal convection,heat conduction and thermal radiation.The method on how to carry out thermal analysis is presented for an independent LNG containment.The case study is carried out with two typical independent LNG tanks.One is a tank with double spherical cylindrical in the LNG carrier,and the other is a tank with single spherical cylindrical on the deck of the ship using LNG as fuels.The result shows the method presented in this paper is a good reference for the structural design with independent LNG containment.

Dynamic evolution in mechanical characteristics of complex supporting structures during large section tunnel construction

The shallow tunnelling method(STM)often uses temporary supports to divide large section tunnels into several closed or semiclosed sections so as to share the upper load.The complex support system composed of primary and temporary supports can ensure safety during tunnel construction.Based on the large section tunnel of Beijing Subway Line 12,the mechanical characteristics of support system by the double-side-drift method(DSDM)during excavation and demolition were analyzed through numerical simulation and monitoring.The study showed that the middle cave excavation was the most critical stage of the DSDM,during which the load on the supporting structure increased significantly.The temporary vertical support bore most of the new load during middle cave excavation.During the demolition stage,the load was redistributed,which caused arch settlement and section convergence.The removal of the temporary vertical support exerted the greatest impact in this process.The lateral temporary inverted arch changed from axial compression to axial tension after the middle and lower caves were excavated.Based on the mechanical characteristics of the support system,some engineering suggestions were proposed for large section tunnel construction.These research results can provide reference for the design and construction of similar large section tunnels.

A Practical Decision Making on Design of Fixed Offshore Wind Turbine Support Structure Considering Socio-economic Impact

Wind energy is considered one of the most promising alternative energy sources against the conventional fossil fuels.However,the deployment of these structures in deep-water for better power production is considered as a complex task.This also has raised the issue regarding selection of appropriate support structures for various sea conditions by considering environmental impact and carbon footprint.This paper considers a jacket like support structure as a case study for an intermediate water depth(50m).The jacket is considered to be located in North of Dutch Sea,and 100-extreme wave is applied as load condition.Here,the presented methodology provides an insight towards environmental/social impact made by the optimized designs in comparison with reference design.

Design and Kinematics Analysis of Support Structure for Multi-Configuration Rigid-Flexible Coupled Modular Deployable Antenna

In order to meet the urgent need for diversified and multi-functional deployable antennas in many major national aerospace projects,such as interstellar exploration,the fourth phase of lunar exploration project,and the industrial application of Bei Dou,a deployable antenna structure composed of hexagonal prism and pentagonal prism modules is proposed.Firstly,the arrangement and combination rules of pentagonal prism and hexagonal prism modules on the plane were analyzed.Secondly,the spatial geometric model of the deployable antenna composed of pentagonal prism and hexagonal prism modules was established.The influence of module size on the antenna shape was then analyzed,and the kinematic model of the deployable antenna established by coordinate transformation.Finally,the above model was verified using MATLAB software.The simulation results showed that the proposed modular deployable antenna structure can realize accurate connection between modules,complete the expected deployment and folding functional requirements.It is hoped that this research can provide reference for the basic research and engineering application of deployable antennas in China.

Slicing and support structure generation for 3D printing directly on B-rep models

Traditional 3D printing is based on stereolithography or standard tessellation language models,which contain many redundant data and have low precision.This paper proposes a slicing and support structure generation algorithm for 3D printing directly on boundary representation(B-rep)models.First,surface slicing is performed by efficiently computing the intersection curves between the faces of the B-rep models and each slicing plane.Then,the normals of the B-rep models are used to detect where the support structures should be located and the support structures are generated.Experimental results show the efficiency and stability of our algorithm.

The development of 3D printing technology and the current situation of controlling defects in SLM technology

With unique manufacturing technology,the additive manufacturing technology divides the three-dimensional object into countless two-dimensional laminates.Compared with the traditional material reduction manufacturing method,it has the characteristics of saving materials,being fast,and especially suitable for single and small batch parts and the rapid manufacturing of parts with complex shapes and internal structures.In this paper,various methods of additive manufacturing technology are reviewed.This paper introduces the characteristics of selective laser melting technology and its forming equipment system.On this basis,the technical defects of selective laser melting technology are analyzed,and the status of controlling defects in SLM technology is explained.In the end,the prospects of additive manufacturing technology are described.

Mechanism and control technology of strong ground pressure behaviour induced by high-position hard roofs in extra-thick coal seam mining

This work aimed at revealing the mechanism of strong ground pressure behaviour(SGPB)induced by high-position hard roof(HHR).Based on the supporting structures model of HHR,a modified voussoir beam mechanical model for HHR was established by considering the gangue support coefficient,through which the modified expressions of limit breaking span and breaking energy of HHR were deduced.Combined with the relationship between the dynamic-static loading stress of supporting body(hydraulic support and coal wall)and its comprehensive supporting strength,the criteria of ground pressure behaviour(GPB)induced by HHR were discussed.The types of Ⅰ_(1),Ⅰ_(2),Ⅱ_(1),andⅡ_(2) of GPB were interpreted.Results showed that types Ⅰ_(1) and Ⅰ_(2) were the main forms of SGPB in extra-thick coal seam mining.The main manifestation of SGPB was static stress,which was mainly derived from the instability of HHR rather than fracture.Accordingly,an innovative control technology was proposed,which can weaken static load by vertical-well separated fracturing HHR.The research results have been successfully applied to the 8101 working face in Tashan coal mine,Shanxi Province,China.The results of a digital borehole camera observation and stress monitoring proved the rationality of the GPB criteria.The control technology was successful,paving the way for new possibilities to HHR control for safety mining.

Tunnel design considering stress release effect

In tunnel design, the determination of installation time and the stiffness of supporting structures is very important to the tunnel stability. This study used the convergence-confinement method to determine the stress and displacement of the tunnel while considering the counter-pressure curve of the ground base, the stress release effect, and the interaction between the tunnel lining and the rock surrounding the tunnel chamber. The results allowed for the determination of the installation time, distribution and strength of supporting structures. This method was applied to the intake tunnel in the Ban Ve Hydroelectric Power Plant, in Nghe An Province, Vietnam. The results show that when a suitable displacement u0 ranging from 0.0865 m to 0.0919 m occurrs, we can install supporting structures that satisfy the stability and economical requirements.

The Application of Pile Foundation Bearing-Retaining Wall Combination Structure in a Mountainous Urban High Fill Project

Pile foundation bearing-retaining wall combination structure is a new type of support structure developed in recent years.This article focuses on the characteristics,advantages,and application scope of the support structure,while combining a variety of algorithms,according to different geological conditions and slope stability,as well as summarizes the pile foundation bearing-retaining wall combination structure force analysis and design methods,taking a high-fill road project in Chongqing as an example.The application of this support structure under special conditions,such as thicker soil layer,steeper sliding surface,weak foundation,and limited slope release conditions,is presented,which illustrates the technical advantages of this support structure and proving that it has several other advantages,including clear force mechanism as well as economic and reasonable structure,thus providing reference for similar projects.

Formation of Hybrid Ring Structure of Cyanurate/Isocyanurate in the Reaction be-tween 2,4,6-Tris(4-Phenyl-Phenoxy)-1, 3,5-Triazine and Phenyl Glycidyl Ether

Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound which were well known as reaction products of cyanate esters and epoxy resins, compounds with hybrid ring structure of cyanurate/isocyanurate were determined. Gibbs free energies of the compound having hybrid ring structure of cyanurate/isocyanurate with two isocyanurate moiety were found to be lower than that of the compound with cyanurate ring structure through calculations. Calculation data supported the existence of hybrid ring structure of cy-anurate/isocyanurate. It was revealed that isomerization from cyanurate to isocyanurate occurs via hybrid ring structure of cyanurate/isocyanurate in the reaction of aryl cyanurate and epoxy.