Coaxial Joints Research Articles

WrapToR composite truss joints: Concept introduction and coaxial joint analysis and demonstration

WrapToR composite truss joints: Concept introduction and coaxial joint analysis and demonstration

Producing of coaxial joints of dissimilar metals with the help of explosion

Producing of coaxial joints of dissimilar metals with the help of explosion

Особливості формування структури коаксіальних з’єднань міді та алюмінію при зварюванні вибухом з вакуумуванням зварювального проміжку

Особливості формування структури коаксіальних з’єднань міді та алюмінію при зварюванні вибухом з вакуумуванням зварювального проміжку

Features of formation of structure of coaxial joints of copper and aluminium in explosion welding with vacuuming of welding gap

Features of formation of structure of coaxial joints of copper and aluminium in explosion welding with vacuuming of welding gap

Induced Currents and AC Losses Models for a Butt-Joint With Rutherfords Shunts

The ITER Central Solenoid (CS) has terminal butt-type joints called Coaxial joints. It was decided to study a design of this joint with rutherford shunts, and to build models for its resistive and inductive behaviors. In particular, the behavior of the joint under magnetic field transients is investigated with various analytical models that are compared with a FEM model. The key point of the study was to verify that the induced currents were reasonable and would not induce flux jumps in the rutherfords. To validate the model, a prototype with simplified geometry was tested in the CEA Josefa facility under various field ramps. The comparison between model and experimental results are presented and discussed.

Demountable Coaxial Clamped Joint For ITER Central Solenoid Module Final Test Program

The ITER Central Solenoid Modules (CSM) are being fabricated at General Atomics (GA) at their Magnet Technologies Center in Poway, CA. Each of the seven modules will undergo final testing at the GA facility to demonstrate their performance at 48.5 kA, 11 T, and at 4.5 K. In order to perform tests on multiple modules, a demountable coaxial joint using indium wires was developed to connect the modules to the feeders. Two full scale joints were fabricated to establish the assembly technique and preliminarily tested (up to 3 kA) on the CSM qualification coil (Cu conductor). The same joint components were then tested using a superconducting jumper (NbTi) and their resistance measured (2.3 and 4.9 nΩ, at 4.5 K, 40 kA). In parallel to measuring the voltage across the joints, a calorimetric evaluation was also performed and it confirmed the low resistance measurements of both joints. Testing of the same coaxial clamped joints on a heat treated Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn jumper took place in February 2019 and the results are reported in this paper. With these acceptable results, the same joint components and assembly techniques will be utilized to connect the 14 joints on the seven CSM (Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn) for full current testing.

A novel 6R metamorphic mechanism with eight motion branches and multiple furcation points

The furcation point in a mechanism is a salient feature of reconfigurable mechanisms and change of a joint from an unconstrained condition to a geometrically constrained condition resulting in naturally link annexing with this geometrical constraint is a typical feature of metamorphic mechanisms. This paper presents a novel 6R metamorphic mechanism by inserting two revolute joints to a Bennett mechanism. From parameters of this novel 6R metamorphic mechanism, the source mechanism before changing is a special case of the Bricard 6R line-symmetric mechanism while the closure equation gives constraint conditions of joints. The geometrically constrained conditions result in variable motion branches of the mechanism. When all joints are unconstrained geometrically, two 6R motion branches can be obtained and when two joints are under geometric constrained, three 4R motion branches can be obtained. Further, three further motion branches with coaxial joints are obtained and motion branch transformation is illustrated with kinematic curves. For each of the motion branches, motion screws of this novel 6R metamorphic mechanism present corresponding geometry morphology and are analysed with screw algebra.

Examination of ITER Central Solenoid prototype joints

The ITER Magnet System will be the largest and most challenging integrated superconducting magnet system ever built. For the Central Solenoid (CS), cable – in – conduit - conductors (CICCs) of nearly one kilometre length are produced, but still, it will be necessary to connect several lengths together to wind the gigantic 110 tonnes coils. The creation of these superconducting joints is one of the most delicate parts of the assembly. There are three types of ITER CS joints: splice joints, coaxial joints and twin – box joints. US ITER, the ITER Domestic Agency of the USA produced a prototype containing all three types of joints. The goal is to test the performance of the joints in the SULTAN facility of the Swiss Plasma Center (SPC), capable of reproducing close – to – service conditions: high magnetic field (up to 11 T background field), high current (up to 100 kA) and high mass flow rate of supercritical helium for cooling. The paper describes the results of a comprehensive examination campaign aimed at understanding the relation between fabrication and performance of the CS prototype joints. The test campaign combines advanced image analysis for the assessment of the void fraction of the conductors with Scanning Electron Microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) to evaluate the quality of the contact between the strands and the sleeve / sole of the joints.

Structural evaluation of coaxial joints for FRP rebars using winding wet fabrics composites

Owing to limit in transportation and production, the connection of FRP rebars is an unavoidable problem. A coaxial joining scheme for FRP rebars using winding wet fabrics and fiber bundle/belt composite is presented in this paper. The experimental results indicate that the connection method is effective. And it has the following characteristics: small size, light weight, high strength, corrosion resistance, easy to construction etc. Facing the development of the engineering application in the future, some works need further research are putting forward.

Development of the bus joint for the ITER Central Solenoid

The terminations of the Central Solenoid (CS) modules are connected to the bus extensions by joints located outside the CS in the gap between the CS and torodial field (TF) assemblies. These joints have very strict space limitations. Low resistance is a common requirement for all ITER joints. In addition, the CS bus joints will experience and must be designed to withstand significant variation in the magnetic field of several tenths of a Tesla per second during initiation of plasma. The joint resistance is specified to be less than 4nΩ.The joints also have to be soldered in the field and designed with the possibility to be installed and dismantled in order to allow cold testing in the cold test facility. We have developed coaxial joints that meet these requirements and have demonstrated the feasibility to fabricate and assemble them in the vertical configuration. We introduced a coupling cylinder with superconducting strands soldered to the surface of the cable that can be installed in the ITER assembly hall and at the cold test facility. This cylinder serves as a transition area between the CS module and the bus extension.We made two racetrack samples and tested four bus joints in our Joint Test Apparatus. Resistance of the bus joints was measured by a decay method and by a microvoltmeter; the value of the current was measured by the Hall probes. This measurement method was verified in the previous tests. The resistance of the joints varied insignificantly from 1.5 to 2nΩ.One of the challenges associated with a soldered joint is the inability to use corrosive chemicals that are difficult to clean. This paper describes our development work on cable preparation, chrome removal, compaction, soldering, and final assembly and presents the test results.

Effect of Recessing in Bondline on Stress in Co-Axial Lap Joint

The effect of recessing on the stresses distributed along the mid-bondline in both standard single lap joints and co-axial ones were analyzed using elasto-plastic finite element method (FEM). The results obtained show that the values of the peak stresses of all the stresses distributed in the mid-bondline were changed greatly as the preformed angle in over lap zone was about 10 0 when the high elastic modulus adhesive is used. The effect of the elastic modulus level on the stress distribution (especially the peak stresses) is small in the middle part of the lap zone. When taken the stress distributed in the middle part of the lap zone into account, there is nearly no significant difference between the peel stress distributed in the standard joint and co-axial single lap joint when the adhesives with lower elastic modulus was used. It is recommended that a co-axial joint is suitable for the recessing joint made by aluminum alloy and a higher elastic modulus adhesive.

Study of the properties of anaerobic adhesives cured in cylindrical joints

Properties of anaerobic adhesive materials during testing and their applications in cylindrical coaxial joints are reviewed.

Durability of Adhesively Bonded Coaxial Joints Assembled into Power Transmission Gear.

The principles of adhesively bonded coaxial assemblies in power transmission gears provide some interesting design possibilities for example, in the attachment of gears to shafts, the savings in machining and material costs can be identified. To evaluate the durability of adhesively bonded coaxial joints applied in power transmission gears, a power circulating durability testing machine was constructed. Using this testing machine, we experimentally investigated the effect of applied mean torque, overlap length and rotational speed on the durability of joints. Static torsional tests were also conducted, and the relationship between durability in the testing machine and static torsional strength was discussed. Furthermore, the stress distribution in joints of this type was analyzed with the finite-element method to investigate the effect of stress distribution within the adhesive layer on the torsional strength and durability of the joint. The main results obtained are summarized as follows. (1) With increase in lap length, the static torsional strength increased. However, the maximum stress in the adhesive layer was almost constant irrespective of the lap length. (2) Durability test data obtained from different lap lengths can be normalized by utilizing the static torsional strength of the joint. (3) Applied torque with constant failure time decreases with increase in rotational speed. This phenomenon is apparently due to fatigue damage to the adhesive layer caused by vibration during rotation.

Coaxial joints in engineering assembly

Coaxial joints occur in a wide range of engineering applications, and a variety of different joining processes are used to achieve the assembly and retention of coaxial components. The metallurgical and mechanical joining methods are briefly reviewed, and the developments in adhesive bonding technology which have led to new concepts in coaxial joint design are discussed in more detail. The importance of surface finish in determining the strength of bonded joints is demonstrated, and the experimental observations are explained by an analytical approach which shows the effects of surface roughness on stress distribution. The potential for application of the different types of joint in coaxial assembly is considered by reference to case studies which show how service demands, material requirements, and manufacturing costs affect the choice of process.MST/363

Coaxial joints in engineering assembly

AbstractCoaxial joints occur in a wide range of engineering applications, and a variety of different joining processes are used to achieve the assembly and retention of coaxial components. The metallurgical and mechanical joining methods are briefly reviewed, and the developments in adhesive bonding technology which have led to new concepts in coaxial joint design are discussed in more detail. The importance of surface finish in determining the strength of bonded joints is demonstrated, and the experimental observations are explained by an analytical approach which shows the effects of surface roughness on stress distribution. The potential for application of the different types of joint in coaxial assembly is considered by reference to case studies which show how service demands, material requirements, and manufacturing costs affect the choice of process.MST/363