Connecting Tube Research Articles

Assessment of Tube–Fin Contact Materials in Heat Exchangers: Guidelines for Simulation and Experiments

This paper describes experiments on finned tube heat exchangers, focusing on reducing the thermal contact resistance at the contact between the pipe and the lamella. Various contact materials, such as solders and adhesives, were investigated. Several methods of establishing contact were tested, including blowtorch soldering, brazing, and furnace soldering. Thermal camera measurements were carried out to assess the performance of the contact materials. Moreover, finite element analysis was performed to evaluate the contact materials and establish guidelines in the fin–tube connection modeling by comparing simplified models with the realistic model. Blowtorch brazing tests were successful while soldering attempts failed. During the thermographic measurements, reflective surfaces could be measured after applying a thin layer of paint with high emissivity. These measurements did not provide valuable results; thus, the contact materials were assessed using a finite element analysis. The results from the finite element analysis showed that all the inspected contact materials provided better heat transfer than not using a contact material. The heat transfer rate of the tight-fit realistic model was found to be 33.65 for air and 34.9 for the Zn-22Al contact material. This finding could be utilized in developing heat exchangers with higher heat transfer with the same size.

Design and performance analysis of multi-section expansion chamber muffler based on Actran

Abstract. In order to compare and analyze the influence of different structural parameters on the muffler performance of multi-section expansion chamber muffler, this paper explores the main factors affecting the noise suppression performance through the transmission loss formula, and it establishes the model of two cylindrical expansion chamber silencer. The muffler expansion chamber is analyzed by changing the section number of the muffler expansion chamber, the cross-section diameter of the front and rear expansion chamber, the length of the front and rear expansion chamber, the length of connecting tube, the arrangement order of expansion chamber with different cross-section area and the arrangement order of expansion chamber with different length. The simulation results show that the muffler volume can be effectively increased by increasing the number of expansion chamber and the cross-section diameter of expansion chamber. The length of the expansion chamber does not show the peak value of the transmission loss curve, which only affects the span of the transfer loss curve; the order of the expansion chamber with different diameters and the arrangement order of the expansion chamber with different lengths have little influence on the transmission loss peak value of the muffler; the change of the length of the connecting tube affects the span of the transmission loss curve, but the peak value of the transfer loss curve is not affected. This study can be used as a reference for the design of a multi-section expansion chamber silencer.

Seismic Performance of Precast Concrete Bridge Piers with Built-In Steel Tube Connection Key

Investigating the seismic behavior of precast concrete bridge piers is crucial in the design process due to the complex stress distribution in the connecting components. To demonstrate the seismic behavior of precast concrete bridge piers with hybrid joint connections, three bridge piers were designed with a scaling ratio of 1:8 and then tested under low cyclic loading conditions. The tests involved varying shapes of steel tube connection keys as parameters. This study involved examining failure modes and crack development, as well as analyzing the hysteretic performance, deformation capacity, energy dissipation, and stiffness degradation of the specimens. Furthermore, a finite element model was developed using ABAQUS, and the validity of the modeling approach suggested in this study was confirmed through tests. The results indicate that the precast piers exhibit reduced concrete damage at the joints. The enhanced strength of the joints is attributed to the incorporation of steel tube connection keys. The circular steel tube connection key integrated into the precast bridge pier offers a superior bearing capacity, energy dissipation, and stiffness degradation compared to the cross-shaped steel tube connection key. The presence of the built-in circular steel tube connection key in the precast bridge pier suggests that it complies with the seismic structural measures and is consistent with the design principle of “strong joint and weak member”.

Observations from opening of a novel geotextile tube connection in field test site

A novel connection configuration for geotextile tubes was proposed, involving the insertion of an auxiliary tube between two main tubes, to ensure proper alignment and leveling when connecting them in a series, thus consolidating individual tubes into a unified structure while maintaining a consistent horizontal level. The novel connection was implemented at a test bed site in the Saemangeum reclaimed area, South Korea, to test exposure to the marine environment including sea waves, sun light exposure and reclamation process. This study presents the observations made upon opening the connection tube after 8 years. The observation shows that the connected geotextile tubes using the proposed auxiliary tube are suitable for use in long-term reclamation projects.

Cyclic axial loading tests on mortar-filled rectangular tube with various connection details

Although a mortar-filled rectangular hollow structural section (RHS) under monotonic loading has achieved large tensile capacity using various connection details and buckling capacity of RHS members, the structural capacity of the mortar-filled RHS tubes has not been investigated under cyclic loading. In this study, the seismic performances of newly developed mortar-filled RHS tubes with various connection details were evaluated under cyclic axial loading. The major test parameters included the end connection type, the thicknesses of the RHS tube, cap plate, and cleat plate, as well as the length of the RHS tube. The test results showed that the RHS tube in all specimens failed by tensile fracture before axial compression failure. The seismic performance of the embedded shear plate end connection with penetrating rebar was superior to that of a conventional welded T-end connection. The test results were compared with the current design code to evaluate the seismic capacity of the RHS tube according to the connection details. Design considerations for the connections of the mortar-filled rectangular tubes were also provided.

Hydrodynamic performance characteristics of small-scale in-situ buoys with critical motion requirements

As the accuracy of high-precision oceanographic measurement instruments increases, the operational requirements for buoy motion become critical. This study focuses on the small-scale in-situ buoy, optimizing buoy configuration to ensure stability and performance. Aiming at the special structure which consists of a large floating column and several small tube connectors, a method for evaluating the hydrodynamic performance is proposed which combines potential flow theory with Morison equation. And the method validity is confirmed using experimental data. The performances analysis of different type buoy with catenary or taut mooring system are developed. According to the critical motion requirements for the long-term stability, the cylindrical type buoy equipped with a catenary mooring system is regarded as the most stable and economical choice, exhibiting a surge motion response of 4.07 m, a heave motion response of 2.89 m, and a pitch motion response of 9.37°. Furthermore, the anchor chain acts as an elastic damper which can mitigate the transient impact of the environmental loads, greatly limiting the amplitude of the longitudinal and heaving motions. And the maximum mooring line tension is 249.28 kN, which is significantly lower than other schemes. The evaluation method offers a technical support for engineering applications.

Application of a Novel Disposable Flow Cell for Spectroscopic Bioprocess Monitoring

The evaluation of the analytical capabilities of a novel disposable flow cell for spectroscopic bioprocess monitoring is presented. The flow cell is presterilized and can be connected to any kind of bioreactor by weldable tube connections. It is clamped into a reusable holder, which is equipped with SMA-terminated optical fibers or an integrated light source and detection unit. This modular construction enables spectroscopic techniques like UV-Vis spectroscopy or turbidity measurements by scattered light for modern disposable bioreactors. A NIR scattering module was used for biomass monitoring in different cultivations. A high-cell-density fed-batch cultivation with Komagataella phaffii and a continuous perfusion cultivation with a CHO DG44 cell line were conducted. A high correlation between the sensor signal and biomass or viable cell count was observed. Furthermore, the sensor shows high sensitivity during low turbidity states, as well as a high dynamic range to monitor high turbidity values without saturation effects. In addition to upstream processing, the sensor system was used to monitor the purification process of a monoclonal antibody. The absorption module enables simple and cost-efficient monitoring of downstream processing and quality control measurements. Recorded absorption spectra can be used for antibody aggregate detection, due to an increase in overall optical density.

Glubam roof truss with riveted glubam connections adopting thin-walled steel tube: Experiment, modeling, and model-updating

Bio-based laminated structures offer a timely solution to meet the pressing demand for resource-efficient and environmentally responsible construction practices in civil engineering. Riveted connections are a kind of commonly used joint and significantly impact the mechanical behaviors of global structure. However, existing studies on the complex behavior of such joints for bamboo-based structures are insufficient. This study investigated the hysteretic behavior of riveted Glued Laminated Bamboo (glubam) connections using thin-walled steel tube and corresponding planar roof truss with thin-walled steel tube connections by experimental and numerical methods. Firstly, cyclic tests were conducted on the riveted glubam connections with thin-walled steel tube to investigate their hysteretic behavior. The test matrix encompasses four distinct connection configurations, carefully selected to assess the connection behavior of glubam. After the investigation of connection behavior, cyclic tests were further conducted on glubam planar roof truss structures to evaluate their global and local hysteretic behavior. Subsequently, the numerical hysteretic models for joints and hybrid roof trusses were developed within the OpenSeesPy framework. To accurately and efficiently calibrate the model parameters, a novel parallel genetic algorithm (PGA) was proposed to carry out an initial calibration on model parameters. Based on PGA, a more comprehensive model updating framework combining the neural network, prior knowledge and PGA was developed to obtain optimal parameters. Finally, the numerical models were successfully validated against the experimental data, demonstrating the effectiveness of the established numerical model and model-updating framework.

Droplet-based microfluidics for engineering shape-controlled hydrogels with stiffness gradient

Current biofabrication strategies are limited in their ability to replicate native shape-to-function relationships, that are dependent on adequate biomimicry of shape, size and spatial heterogeneity, within cell-laden hydrogels. In this study, a diffusion-based microfluidics platform is presented that meets these needs in a two-step process. In the first step, a hydrogel-precursor solution is dispersed into a continuous oil phase within the microfluidics tubing. By adjusting the dispersed and oil phase flow rates, the physical architecture of hydrogel-precursor phases can be adjusted to generate spherical and plug-like structures, as well as continuous meter-long hydrogel-precursor phases (up to 1.75 m). The second step involves the controlled introduction a small molecule-containing aqueous phase through a T-shaped tube connector to enable controlled small molecule diffusion across the interface of the aqueous phase and hydrogel-precursor. Application of this system is demonstrated by diffusing co-initiator sodium persulfate (SPS) into hydrogel-precursor solutions, where the controlled SPS diffusion into the hydrogel-precursor and subsequent photo-polymerization allows for the formation of unique radial stiffness patterns across the shape- and size-controlled hydrogels, as well as allowing the formation of hollow hydrogels with controllable internal architectures. Mesenchymal stromal cells are successfully encapsulated within hollow hydrogels and hydrogels containing radial stiffness gradient. The cells are observed to respond to the microscale spatial heterogeneity as evidenced by increased cell elongation in softer core regions of the hydrogel as compared to the peripheral stiffer hydrogel regions, as well as stiffness-dependent nuclear accumulation of the yes-associated protein mechano-regulator. Finally, breast cancer cells are found to phenotypically switch in response to stiffness gradients, causing a shift in their ability to aggregate, which may have implications for metastasis. The diffusion-based microfluidics will mimic native shape-to-function relationship and provides a platform to further study the roles of micro- and macroscale architectural features that exist within native tissues.

Introduction to a novel geotextile tube connection construction method: A case study of test site and field application

One particular challenge in constructing geotextile tubes is ensuring proper alignment and leveling, especially when connecting them in a series. This study introduces a novel connection configuration to address this challenge by inserting an auxiliary tube between two main tubes. The proposed connection method offers the advantage of consolidating individual geotextile tubes into a unified structure while maintaining a consistent horizontal level. The proposed connection technique was successfully applied both at test site and on dry construction platform for bridge construction. This study is beneficial for practicing engineers as it presents a new and effective method for connecting geotextile tubes, offering valuable insights into its practical application.

Experimental and numerical investigations on the axial compression performance of precast geopolymer concrete sandwich wall panel

This paper investigated a novel precast concrete sandwich panel (PCSP) which made by the geopolymer concrete and enabled by the glass fiber reinforced polymer (GFRP) hexagonal tube connector. Six precast geopolymer concrete sandwich wall panel (PGCSP) specimens were fabricated and tested under axial compression load. The investigating parameters included the connector spacing, panel height, and panel thickness. The failure mode, axial load capacity, load-axial deflection relationship, and load-concrete strain relationship were studied and discussed. Moreover, two-dimensional (2D) finite-element (FE) analysis was conducted to reproduce the test. Parameter analysis was then performed to modify the axial load capacity formula in the Chinese code GB50010-2010. The results indicated that: all specimens exhibited large eccentric compression failure due to the second-order effect, which was caused by concrete crushing and horizontal cracking in the two wythes, respectively; with the decrease of the connector spacing, the crushing area of the specimens would be enlarged, the out-of-plane lateral deformation would be decreased, and the axial load capacity decreased by 17 % and 42 % when the connector spacing changed from 300 mm to 600 mm and 900 mm, respectively; with the decrease of the panel height and the increase of concrete wythes thickness, the axial load capacity of the specimens almost presented a linear increase; the established 2D FE model and the modified formula effectively reflected the axial load capacity of the specimens.

Improved air gap permeance modelling for single-slice magnetic equivalent circuits of skewed induction motors

PurposeWhen rotor and stator teeth are close, the connecting air gap flux tube's cross-sectional area exceeds the tooth overlap area. This flux fringing effect is disregarded in the air gap permeance calculation of single-slice magnetic equivalent circuits (MECs) of electric motors with skewed rotors. This paper aims to extend an air gap permeance calculation method incorporating flux fringing for unskewed rotors to skewed and radially eccentric rotors.Design/methodology/approachAssuming axial independence, the unskewed air gap permeance is rotated according to the skew and integrated along the axial dimension, resulting in a first method. The integral is approximated analytically, resulting in a second method. Results are compared to a commonly used reference method and validated using a non-linear finite element method (FEM) simulation.FindingsThe proposed methods provide better alignment with the FEM validation compared to the reference method for skewed rotors and common rotor eccentricity, i.e. below 50% of the air gap length. The analytical method is shown to be competitive with the reference method regarding computational time cost.Originality/valueTwo novel air gap permeance methods are proposed for single-slice MECs with skewed rotors. Their characteristics are discussed and validated.

Load-carrying capacity of hole threads in TOBs bolted curved T-stubs to circular steel tube connections

This study investigates the load-carrying mechanism and proposes precise strength prediction methods for hole threads in Thread-fixed One-side Bolts bolted curved T-stubs to circular steel tube connections. A series of parametric analysis was performed with an advanced 3D finite element model considering critical parameters including tube wall thickness, bolt angle and bolt size. The axial load distribution along the hole threads and the shear stress distribution at the thread root were analyzed in detail. It was found that there were three typical load distribution patterns along hole threads, which were (1) linear pattern; (2) concave parabola pattern; and (3) convex parabola pattern, and the ratio of bolt stiffness to tube wall stiffness was identified as the pivotal factor affecting the axial load distribution. Meanwhile, the analysis results indicated that the bending moment on the TOBs did not affect the load distribution along hole threads, but led to a non-uniform stress distribution along the thread in the same turn. In the end, the prediction formulas for the carrying capacity of hole threads are presented by modifying Yamamoto’s equation based on the analysis findings. The formulas are validated against the finite element analysis results and previous test results. The prediction can reach the highest accuracy when adopting the proposed failure criterion 2, with average errors of − 0.001 and − 0.002, respectively, demonstrating the accuracy and reliability.

Utilizing phased array ultrasound technique to examine seal surface contact status in premium connections

Premium connections are commonly employed in wells subjected to high temperature and high pressure (HTHP) conditions. The key parameter in evaluating the sealing capability of premium connections is the contact condition between the sealing surface. This paper presents a method based on phased array ultrasound testing (PAUT) technique to examine the metal-to-metal contact states of the seal surface in premium conditions, and presents experimental work on contact status of the seal surface in premium tubing connections using PAUT, testing impacts of torque, seal surface defects and thread compounds dosage. The experimental findings demonstrate an inverse relationship between the observed ultrasonic reflection amplitude and the applied torque on the premium. Additionally, there is a robust exponential correlation manifested between the ultrasonic reflection amplitude and the torque exerted on the premium. The ultrasonic reflection amplitude at the defect of the seal surface increases. Under equivalent make-up torque conditions, the ultrasonic reflection amplitude on the sealing surface of premium connections escalates as the dosage of thread compounds diminishes, and the importance of precise control of the amount of thread compound used was confirmed. These data demonstrate that PAUT provides a reliable detection technique for performance assessment on premium connections, both in quality control and field inspection.

Velocity (μPIV) and temperature/concentration (μLIF) measurements in a dual serpentine microchannel of a micro DMFC stack

Herein, we present an experimental study of the flow, as well as the thermal and concentration characteristics of two serpentine microchannels, via micro particle image velocity/micro laser induced fluorescence optical visualization techniques, which simulate the flow channels at the anode of a typical micro direct methanol fuel cell stack (two cells: Cell A/B). The flow channel consists of two serpentine microchannels. Each channel has one channel and six paths. Channels A and B were connected by a connecting tube to create an entire flow loop with methanol as the working fluid. The velocity, temperature and concentration distribution along the channel downstream for 5.7 ≤ Re ≤ 594 were visualized and measured. At a particular operation condition of methanol flow rate of 1 ml/min and concentration of 1 M at stack temperature of 25 °C, both in series and parallel arrangements were examined with a peak power density of 61.4 mW/cm2 (current density 120 mA/cm2 and voltage 1.0 V) and of 75 mW/cm2 (current density 120 mA/cm2 and voltage 1.2 V), respectively. CO2 ellipse-like bubbles were found at the up/down stream corners with a definite major/minor axis length. Furthermore, relevant (f, Nu, and Sh) correlations regarding the relationship of the methanol solution pumping power, heat transfer and utilization with Reynolds number in form of power law were developed with 95 % accuracy of experimental data. With these related results, it might be beneficial to the configuration design of the μDMFC stack.

Resolving Uncertainties in the Quantification of Trace Elements within Organic-Rich Boreal Rivers for AF4-UV-ICP-MS Analysis.

Over the past few decades, asymmetric flow field-flow fractionation (AF4) has emerged as a robust technique for the separation of colloid-associated trace elements (TEs) in aqueous samples. Nevertheless, little is known about potential artifacts and how to control them when measuring the concentrations of colloid-associated elements at low (μg L-1) or ultralow concentrations (ng L-1) using AF4-UV-ICP-MS. Water from a boreal river was selected as a challenging test material due to its high concentrations of dissolved organic matter (DOM) and Fe-rich colloids. These colloids are expected to be significant contributors to artifact occurrence, even in a metal-free, ultraclean laboratory. The results show that the adsorption of Mn, Co, Ni, Cu, and Pb onto acid-cleaned, non-channel surfaces (such as connection tubing and autosampler) accounted for up to 48% of TE loss. These losses on non-channel surfaces also represent potential sources of cross-contamination for Co, Ni, Cu, and Pb. New, uncleaned poly(ether sulfone) membranes are also sources of contamination for Ni and Cu. Analytical bias may exist in the measured concentrations of TEs, primarily due to the potential carryover of weakly adsorbed TEs (e.g., Ni and Cu) on the system surfaces by colloids in the samples (e.g., DOM). On the other hand, colloids in the samples can also act to gradually remove contaminants from the surfaces. For these types of DOM-rich waters, preconditioning the AF4 system using 40 mg C L-1 of Suwannee River Natural Organic Matter (SRNOM, pH = 7) is recommended to mitigate the impact of membrane fouling and carryover. A comprehensive strategy for minimizing instrumental artifacts is presented and discussed.

Optimizing ultrasound Doppler measurement precision: a comprehensive experimental approach

Experimental studies were conducted utilizing advanced equipment comprising a generator, tubing system, pump module, sonographer, and PC. The generator serves as the central component connected by tubes to the pump, forming a closed circuit. A tee in the tubing set prevents Doppler fluid leakage, with the fluid poured through a special funnel into the circuit post-connection. The Doppler fluid is evenly mixed by shaking its bottle to enhance signal strength. The entire system is sealed. The centrifugal pump generates continuous flows; different power modes were tested for 30 minutes each, with frequency shifts measured at angles α=15°, 30°, and 60°. Pump disconnection from the power supply prevents liquid entry during tubing connection. The pump module housing includes ventilation holes. A 3 by 8 cm Doppler prism, treated with ultrasonic gel, was connected to the tubing to capture data. A sonographer emitting signals at 2 MHz, with a gain range of 10 to 40 dB, was utilized for sound spectra analysis. High-mode operation, 4 microseconds pulse duration, and a 32 microseconds receiver gate were set. The ultrasound apparatus dimensions were 230 x 236 x 168 mm, with a power consumption of 27 VA. Data visualization was facilitated by an LED panel, with adjustable acoustic signal volume. A USB interface enabled connection to a PC for ease of use and data analysis. Special software facilitated graph generation depicting frequency vs. time dependence measurements. Frequency analysis yielded average (f-mean) and maximum (f-max) frequency values, with f-mean utilized to measure Doppler effect frequency shift. The presented data showcases various pump speeds and incidence angles, each yielding distinctive frequency characteristics.

SAFE PERFORMANCE OF WORKS IN CONSTRUCTION AND HOUSING AND COMMUNAL SERVICES USING THE ORIGINAL SCAFFOLDING DESIGN

Our development relates to construction, namely scaffolding and scaffolding used when working at height. It is intended for fencing the work area when carrying out various types of work, for example, when performing brickwork from scaffolding. In construction, where safety and efficiency play a crucial role, the correct selection and use of scaffolding are integral to every successful project. We have proposed a patent-protected solution. It is a scaffolding railing consisting of vertical support posts hinged with horizontal crossbars, characterised by the fact that each support post is made in the form of a telescopic connection of pipes of different diameters with the possibility of extending them from each other and is fixed with the help of an existing locking device. The hinge connection of horizontal crossbars with them, except the upper row of such bars that are railing, is made in random order, for example, by attaching a hinge to the upper end of the upper tube of the smallest diameter, and is carried out using additional ring elements mounted on the corresponding telescopic connecting tubes. The inner diameter of each of these annular elements, exceeding the outer diameter of the tube on which it is mounted, is less than the outer diameter of the next subordinate telescopic tube. Thus, it can move only vertically in a telescopic connection within this and above pipes. It makes it possible to support each of the ring elements with horizontal crossbars attached to them under their weight at a certain level of height of the vertical support post, determined by the height of the underlying tube of the telescopic connection. At the same time, the lower horizontal crossbar is hinged to the ring element of the largest diameter, put on the lower tube of the telescopic connection, and rested directly on the working flooring made in the form of a sideboard. The proposed device is not technically complex to implement. Its use increases the workers’ productivity, improves the working conditions, and ensures the safety of various construction works. Keywords: safety, construction, ease of use, prototype, fencing, scaffolding.

AS A MEANS OF REDUCING THE LEVEL OF EXTERNAL NOISE CHASSIS KRAZ-6511NE

Ukraine’s full-scale war with its northern neighbor has been going on more than two years now. One of the most important laws of war is: “If you don’t detect it, you don’t hit the target.” It’s about masking. In wartime, the camouflage properties of a military vehicle are especially relevant. There are a number of ways to improve them. One of them is reducing the external noise level of a military vehicle. Using the example of the KrAZ-6511NE chassis, one of the ways to reduce noise is considered. The BM 9P140 “Uragan” antiircraft missile system is placed on this chassis. The developed silencer has the ability to change its frequency response synchronously with the change in the engine crankshaft rotation frequency. The developed muffler is a well-known twochamber reactive muffler, which is modified by the ability to change the effective lengths of the chambers. A diagram showing the operation of the developed noise muffler is given, where the main elements are: two muffler chambers, a connecting tube, piston drive mechanisms of the first and second muffler chambers, respectively, an electric motor, a control unit, and a sensor for determining the frequency of rotation of the crankshaft. The acoustic efficiency of this muffler was determined with fixed geometric parameters (outer diameter, diameters of the inlet and outlet pipes) and variable effective lengths of both chambers, families of frequency characteristics were constructed for various combinations of the muffler’s geometric parameters. To construct graphs, code was written in Python, which uses the NumPy and Matplotlib libraries. As a result of the introduction of the developed noise muffler, it is predicted that the external noise level of the KrAZ 6511НЕ chassis will decrease by 5-7 dBA in the speed range of 45-85 km/h.

Analysis of guidance and levitation forces between HTS magnets and conductive tubes for Hyperloop

High-temperature superconducting (HTS) magnets combined with linear synchronous motors and electrodynamic suspension (EDS) are considered as one of the most suitable technologies for Hyperloop. However, HTS magnets on pods generate strong magnetic fields, inducing eddy currents on conductive tubes when pods undergo movement through conductive tubes. The induced eddy currents affect HTS magnets, leading to electromagnetic (EM) drag, guidance, and levitation forces on the pods, thus reducing the propulsion efficiency and dynamic stability of pods. This study continues the existing research on EM drag forces between HTS magnet and tube for Hyperloop by comprehensively analyzing the EM guidance and levitation forces between HTS magnets and conductive tubes. Importantly, the full-scale 3D finite element analysis (FEA) simulations show that different steel tubes, such as AISI 1010 and high-manganese (Hi-Mn) steels, should be adopted, depending on the operating velocities, v, to avoid attractive forces in the guidance direction decreasing horizontal stiffnesses, For example, Hi-Mn tubes generating repulsive guidance forces are adopted when v is below 300 km/h while AISI 1010 tubes are used when v is over 300 km/h to minimize the construction cost of vacuum tubes to guarantee the increase in kx. For the proposed concept, the effect of the different tube connections on guidance and levitation forces is confirmed by the full-scale 3D FEA simulation. Moreover, levitation forces generated between HTS magnets and conductive tubes are nearly 0.5% of the EDS forces of pods, i.e., 200 kN over v of 150 km/h in the levitation direction. Therefore, the effect on vertical stiffnesses, ky, might be limited. In the end, to validate the proposed tube connections, the effect of the two different tube connections on guidance and levitation forces is confirmed by the full-scale 3D FEA simulation, and it was found that the sudden change in the guidance and levitation forces could be low enough to be neglected in the acceleration (from Hi-Mn to AISI 1010 steel tubes) and deceleration (from AISI 1010 to Hi-Mn steel tubes) regions.