Wire Cross Section Research Articles

Study on Breaking Concrete Structures by Pulse Power Technology

Using pulse power technology to break concrete structures can reduce environmental pollution, save energy, and increase safety and reliability. The whole process of concrete beam subjected to shock wave generated by pulse power discharge was simulated and analyzed. An experiment of breaking reinforced concrete beams by metal wire explosion in liquid was carried out. And the main parameters are pulse power discharge voltage, copper wires section size, concrete beam material strength, drilling parameters, etc. The results show that with the increase of discharge voltage and the total area of copper wire cross section between electrodes, the breaking effect of concrete beam is obviously improved. The breaking effect of the beam is slightly improved when the concrete strength is reduced. The breaking effect of concrete beams with 40 mm aperture is better than that of concrete beams with 50 mm aperture. As the distance between adjacent boreholes decreases, the fractures are easier to connect. According to the test results, the formulas for calculating the crack width of concrete beams were proposed, which takes the output voltage, the number of copper wires between electrodes, the hole spacing, the strength of concrete and other key parameters as independent variables. The calculated results agree well with the test results.

Violation of magnetic flux conservation by superconducting nanorings

The behavior of magnetic flux in ring-shaped finite-gap superconductors is explored from the view-point of the flux-conservation theorem, which states that under the variation of an external magnetic field ‘the magnetic flux through the ring remains constant’ (see, e.g., Landau and Lifshitz 1960 Electrodynamics of Continuous Media (New York: Pergamon)). Our results, based on the time-dependent Ginzburg–Landau equations and COMSOL modeling, made it clear that in the general case this theorem is incorrect. While for macroscopic rings the corrections are small, for micro- and nanorings they become rather substantial. The physical reasons behind this effect are discussed. The dependence of flux deviation on ring size, bias temperature and the speed of external flux evolution is explored. The detailed structure of flux distribution inside the ring opening, as well as the electric field distribution inside the ring wire cross section, are revealed. Our results and the developed finite element modeling approach can assist in elucidating various fundamental topics in superconducting nanophysics and in the advancement of nanosize superconducting circuits prior to time-consuming and costly experiments.

Enhanced elastocaloric stability in NiTi alloys under shear stress

Significant elastocaloric effects (eCE) generated from stress-induced B2↔B19’ transition under axial load in NiTi shape memory alloys have already been proved. However, the huge hysteresis of B2↔B19’ transition directly leads to severe functional fatigue, which restricts its practical application. Here, we prepared linear NiTi spring using Ni50.8Ti49.2 wire with diameter of 300 μm aiming at converting normal stress into shear stress considering the fact that martensitic transition is achieved by shear deformation. An isothermal entropy change of ∼41 J/kg·K as well as an adiabatic temperature decrease of −16.8 K have been obtained in present spring. Furthermore, no significant degradation of elastocaloric strength emerged after 254 cycles, while only ∼2.5 K temperature degradation after 1505 cycles. Such superior stability of elastocaloric effect was mainly attributed to pure shear stress condition and gradient martensitic transition (MT) on the wire cross-section during a superelasticity cycle, which effectively reduced transition actuation load and avoided adverse factors under normal stress condition. Therefore, our spring allows for not only stable and huge caloric effect but also fast cycle frequency, thus, being attractive for micro-cooling devices or heating pumps.

To Compare the Stress Magnitude on Roots of Mandibular Incisors at Different Inclinations With Different Arch Wires During Intrusion Mechanics—A Fem Study

Introduction: Force is applied through brackets in fixed mechanotherapy which generates stress in periodontal ligament and root of the teeth and is difficult to measure directly. Finite element analysis is used as a solution for understanding this biomechanical response. So the aims and objectives of this study were to evaluate the stress magnitude induced in the labial and lingual surface of mandibular incisors using superelastic NiTi arch wires of different cross-section at different inclination through finite element analysis. Materials and Methods: Finite element model of all mandibular teeth including periodontal ligament, alveolar bone, buccal tubes, brackets, and arch wire were constructed using mechanical elastic properties of the materials. Three different NiTi arch wires, round (0.016″), square (0.016″ × 0.016″), and rectangular (0.016″ × 0.022″), were placed into the bracket slots and models were constructed which were analyzed for stress distribution on root surface and periodontal ligament with 3 different cross-sections at 90°, 100°, and 110° with Ansys Version 14 software. Conclusion: Labial stress was found highest in round arch wire as compared to square and rectangular wire. Lingual stress was found to be slightly more in rectangular wire as compared to round and square arch wire.

Short circuit fire risk assessment in investigating and examining fires caused by emergency modes in overhead transmission lines

Emergency modes (short circuits) in electric power system and equipment are the main technical cause of fires. However, it is not always possible to prove the involvement of a particular operating mode in a fire. The fire hazard can be due to three components: a fuel load, an oxidizer and an ignition source. Since overhead transmission lines are used in an open space, they are oxidized. The presence of a fuel load is confirmed by a fire. The source of ignition should be identified. The aim of the study is to develop an algorithm for assessing the fire hazard for short circuits in overhead transmission lines with 1000 V. The study was conducted using scientific analysis, physical experiment and simulation. The ignition source is due to the appearance of an energy source with parameters sufficient to ignite a fuel load. The probability of ignition in overhead line wires depends on the probability of occurrence of the short circuit itself ( Qi (v1) ) , the probability of failure of protection devices ( Qi (v2) ), and the probability that the electric current value in the event of a fault is in the range of fire hazard values (Qi(z)). The values of the first two components are determined on the basis of statistical data, taking into account the theory of reliability. The third component is based on the experiment results. The experimental studies made it possible to establish the ranges of fire hazard values for uninsulated aluminum wires of various cross-sections, thereby providing the possibility of calculating ( Qi (z). Using the data obtained and information about the nature of changes in short-circuit currents and performance characteristics of protection devices, depending on the line length, an algorithm for assessing the fire hazard for a short circuit was developed. The results make it possible to assess the fire hazard for short circuits in various sections of the electrical network, made by overhead transmission lines, and to establish the involvement of sparks generated by short circuits in a fire

Contactless Measurement of Integrity of Silicone Coating on Self-Expandable Esophageal Nitinol Stents.

A stent is a mesh tube inserted into a natural passage in the body to prevent disease induction. Self-expandable esophageal nitinol stents such as SX-ELLA Stent Esophageal HV (HV Stent Plus) can be indicated for palliation of malignant esophageal strictures, for the treatment of benign esophageal strictures that are refractory to standard therapy and for the treatment of esophago-respiratory fistulas. A silicone-stent coating is used for tumor in-growth prevention and esophago-respiratory fistula occlusion. The thickness of the stent and the overall integrity of the silicone coating of all wires indicate the overall mechanical properties of the esophageal stent and the resistance to external adverse events such as corrosion and mechanical and chemical resistance. The polymer multicomponent epoxy resin - a mixture of Epon and Durcupan - was used as a method for robust sample stabilization. A cutting system using a thin water beam with a powder (Blue Line) was chosen as the best variant to obtain 6 samples for both-sided measurement (10 measuring sides). The optical microscopic reflective light method was used to examine wire crossing points in the sections. Fifty values were measured on either sample side for the internal, external and mesh thickness of the silicone stent layer. The wire crossing points were selected so that the silicone layer structure could be clearly seen, and the wires approached each other most closely. Only approximately 4 to 8 crossing points in each section could be measured when applying this approach. The resolution of the microscope and calibration (based on the camera used) was 0.677 μm/pixel. Additional data could be obtained on 8 planes. Two boundary samples were destroyed by the cutting process. Whole coating of the stent was around all mesh wires, especially in areas with higher mechanical stress (wire crossing). The minimum detectable and admissible value determined for all 3 measuring areas (internal, external, mesh) on the wire crossings was 6.77 μm, i.e., 10 pixels, based on the microscope resolution and manufacturer's methodology. The results were characterized by p < 0.001 for all 3 parameters. We tested opposite samples in each section to verify the section quality and data consistency. For the 4 areas, the data were significantly different, but the thickness differences were only on the order of units percent, so the measurements were not appreciably affected. We assume that the material cutting loss, making up 1-2 mm, contributed to the differences in the sections. We examined the overall integrity of the silicone coating of the esophageal stent. The method of HV stent anchoring in a polymeric bath followed by cutting with a waterjet and sample measurement under an optical microscope proved to be very simple and reliable. Sufficient thicknesses of the silicone layer on the wire cross sections were verified. The coated silicone layer thickness appeared to be significantly different along the stent from the proximal part to the distant part, presumably due to the manufacturing technology.

Strengthening and reconstructionof drilling core pipe for engineeringand geological exploration

Currently, there is a tendency to increase the depth of gaseous and liquid fossils extraction. Therefore, prospecting and developing new deposits is promising. There is also a need to create new freshwater sources and implement relevant geological work based on this need. It is essential to have information about the characteristics of the explored slabs and the geology of the fields in general. Implementation of engineering and geological core drilling exploration is the most acceptable and provides the necessary data. Here, the peculiarities of the technological schemes of the process implementation make it possible to obtain separate sections of structures at a depth of the drilling equipment. It is essential to use traditional equipment, recommended for decades and provides the necessary results [1–3]. In the drilling process, you can achieve different diameters and depths of wells execution, obtain fossil samples etc. Engineering and geological exploration drilling is now taking on increased use in various industries [3]. Therefore, the problem of providing high- quality drilling tools, the stability of their operating characteristics, and the possibility of usage in different conditions is an urgent need today. Modern drilling problems determine the usage of components of the core set with the appropriate physical and mechanical characteristics. Especially it relates to elements close to the drilling tool and the place of fossil; destruction – drill pipe. It is installed immediately after the crown core drill and receives almost the same loads and effects during working [1–3]. Conditions for the implementation of the process of core drilling are characterized primarily by the effect on the elements of the significant axial and twisted core set forces. There is the influence of the corrosive and active environment of the fossil in the washing and lubricating liquids well, etc. High temperatures are also observed at the drilling sites [3], which negatively affect the working tool and speed up its operation. As a result, there is an intensive shock, and abrasive core pipe wear and operation indicators change their constructive size. As a result, it is necessary to replace the operated drill string periodically. Considering modern technical and economic factors, it may be decided to repair a pipe to its original size in many cases. There are tasks for providing the appropriate characteristics of the core pipe surface. It is possible to model such properties of the new surface that functionally the best meet the conditions of the drilling process of a given geological formation. The peculiarities of applying the therapeutic layer on the surface of the core pipe are investigated in work. The experience shows that using electric arc surfacing under the flux layer is expedient. This provides the necessary adhesion of the applied layer and promotes obtaining resistance to the operation surface of the core pipe. At the same time, there is high-quality protection and the possibility of additional alloying through the flux-slaggy welding bath. Using electrode powder type wires creates conditions for flexibility to achieve the established characteristics of functional layers [4–6]. The filling flux, located in the cross-section of the electrode wire, can be easily changed by chemical composition. At the same time, it is possible to make relatively small parties of a wire with the set characteristics. The technological scheme justification about the core pipe surfacing is performed. It provides the previous displacement of the electrode butt size from the zenith of the core pipe to prevent the welding bath from spreading. The structural pipe size , the requirements for residual deformations, and the conditions of shapping the welded layer show the practicality of welding on a helix.

The Texture Developed by Manufacturing the Spring Made of SWOSC-V

The texture of springs is related to fatigue, creep, and especially strength. We investigated the microstructure in order to clarify the changes of the texture during the manufacturing process of the springs, and to contribute to further strengthening of springs. In this study, we simulate the texture produced by drawing and coiling wires in the spring manufacturing according to the predictive theory of crystal rotation based on Katoh's theory, which is based on the theory of Taylor et al. Also, we observed the crystal structure of the drawn and oil-tempered wires by electron backscattering diffraction (EBSD), and it was observed that the axial direction of crystal orientation rotates toward <110>. This result follows the predicted ones. Next, in order to predict the crystal direction rotated by coiling, we used finite element analysis (FEM) to identify the plastic strain generated during the coiling process, and input them to that theory for crystal rotation. The results show that the axial crystallographic orientation <110> relaxes on the outside of the wire cross section and also, while on the inside, the orientation accumulated around the crystallographic orientation <110> on the inside during the coiling process.

Influence of drawing speed on thin wire mechanical properties and microhardness

A general idea of the steel cord and the process of drawing a thin steel wire is given. It has been determined that the properties of a thin wire influences the properties of a steel cord. At the stage of fine drawing and twisting into a steel cord, the wire receives the final set of mechanical properties. It has been determined that the properties of a thin wire are influenced by the degree of deformation, the rate of deformation at the stage of drawing, and the uniform of deformation. The necessity of increasing the uniformity of the distribution of deformations in the process of drawing a thin wire is determined. Increasing the uniformity of the microhardness distribution shows an increasing the uniformity of the deformation&rsquo;s distribution. High uniformity of deformation distribution increases the technological properties of the wire, increases its quality. The influence of the drawing a thin wire speed on the mechanical properties is investigated. The influence of the drawing speed on the uniformity of the deformation&rsquo;s distribution in the cross-section of a thin wire was investigated by the method of measuring the microhardness. Diagrams of distribution of values of microhardness on wire cross-section for the studied drawing speeds are presented. Microhardness values can be used to determine the mechanical properties of the wire samples. This makes it possible, by measuring the microhardness of the wire cross section, to assess the nature of the metal mechanical properties distribution in the wire cross section. The optimal drawing speed is shown at which the most uniform distribution of deformations is observed. The dependence of the microhardness over the wire cross section average value on the drawing speed is proposed. With an increase the drawing speed, the microhardness of the wire increases.&nbsp;

Numerical comparison study on heat transfer enhancement of different cross-section wire coils insert with varying pitches in a duct

Heat transfer enhancement (HTE) efforts spent during the last half-century have become one of the most important working areas of researchers from both academia and industry. One of the most popular passive methods, with regard to the price-performance ratio, is to place wire coils in a pipe or duct. In this study, the heat and pressure drop characteristics of diamond, triangular, and circular cross-sectional wire coils (DWC, TWC, and CWC) in a square duct were investigated by using the FLUENT program. In addition to the cross-section examination, the thermo-hydraulic behavior of three different pitches (p = 54, 72, and 90 mm) for the specified geometries were also investigated. The Reynolds number was between 4387 and 18,415. The square duct was 1.25 m in length, and was 18 mm in diameter. The results showed that the Nusselt number of CWC, TWC, and DWC were higher than that of a smooth pipe within 38–88%, 37–93%, and 38–98% range, respectively. The friction of CWC, TWC, and DWC was observed to be higher than that of a plain tube within a range of 87–278%, 82–266%, and 107–366%, respectively. The TWC with 90 mm pitch showed the highest heat transfer performance evaluation criteria (PEC) with a performance coefficient of 1.3 at Reynolds number of 4504, whereas the DWC with 54 mm pitch was observed to show the lowest PEC. Thus, the as-obtained PEC, which is 30% higher than that of a plain tube, indicates the prominence and effectiveness of the numerical study in increasing the heat transfer.

Fatigue tests of superelastic NiTi wires: an analysis using factorial design in single cantilever bending

This paper investigates the fatigue behavior of superelastic NiTi shape memory alloy thin wires with circular and rectangular cross-sections under single cantilever bending mode. A dynamic mechanical analyzer operating in single cantilever mode is employed as a testing machine. The fatigue life of the wires was analyzed at different strain amplitudes and loading frequencies. The simultaneous influence of these parameters was assessed through a factorial design with replication. Circular wires have higher fatigue life compared to rectangular wires. Higher strain amplitudes decrease the fatigue life of both circular and rectangular cross-section wires. On the other hand, the loading frequency strongly affected the rectangular cross-section wire, while having a significantly weaker effect on the circular wire. The NiTi wires showed fatigue lives between 103 and 105 cycles in the evaluated range of strain amplitude, which falls within the fatigue life observed for shape memory alloy (SMA) wires under similar loading conditions. Furthermore, the factorial design proved to be a valuable tool in the study of fatigue life of NiTi SMA, especially for the visualization and interpretation of the effect of the chosen variables.

A Method for Determining the Impact of Ambient Temperature on an Electrical Cable during a Fire

Evaluating environmental conditions that trigger fire-fighting equipment is one of the primary design tasks that have to be taken into account when engineering electrical systems supplying such devices. All of the solutions are aimed at, among others, preserving environmental parameters in a building being on fire for an assumed time and at a level enabling safe evacuation. These parameters include temperature, thermal radiation, visibility range, oxygen concentration, and environmental toxicity. This article presents a new mathematical model for heat exchange between the environment and an electric cable under thermal conditions exceeding permissible values for commonly used non-flammable installation cables. The method of analogy between thermal and electrical systems was adopted for modelling heat flow. Determining how the thermal conductivity of the cable and the thermal capacity of a conductor-insulation system can be applied to calculate the wire temperature depending on the heating time t and distance x from the heat source is discussed. Thermal conductivity and capacity were determined based on experimental tests for halogen-free flame-retardant (HFFR) cables with wire cross-sections of 2.5, 4.0, and 6.0 mm2. The conducted experimental tests enable verifying the results calculated by the mathematical model.

Study on the subsurface damage depth of monocrystalline silicon in ultrasonic vibration assisted diamond wire sawing

Diamond wire sawing is one of the key technologies in solar cell manufacturing process and semiconductor chip manufacturing process. The subsurface damage depth (SSD) affects the quality of machined surface in diamond wire sawing, which must be evaluated. In this paper, a mathematical model of the SSD in monocrystalline silicon wafers induced by ultrasonic vibration assisted diamond wire sawing (UAWS) was proposed. In this model, the input is the depth and deflection angle of the median crack, the depth and length of the lateral crack, and ultrasonic vibration, and the output is the residual SSD on the chip. According to the model, the variation of SSD with position angle of diamond abrasives under ultrasonic vibration was analyzed on the cross section of wire saw, and the influence of shielding effect about median crack on SSD under ultrasonic vibration was analyzed later. Then, a finite element model (FEM) of diamond wire sawing monocrystalline silicon was established by ABAQUS,and the SSD under different slicing parameters was simulated. Finally, the interface bonding method was used to measure the SSD of monocrystalline silicon wafer. The experimental results showed that the SSD increases with the increase of the wire saw feed rate, and decreases with the increase of the wire saw speed and the workpiece rotation speed. The SSD in wafer sliced by UAWS is 18.95% on average lower than that in wafer sliced by conventional wire sawing (CWS). The maximum error between theoretical of mathematical model and experimental values is 15.9%, which verifies the validity of the mathematical model.

The cross-sectional effects of ribbon arch wires on Class II malocclusion intermaxillary traction: a three-dimensional finite element analysis

BackgroundThe application of intermaxillary traction is often accompanied by the unexpected movement of dentition, especially anchorage teeth. The aim of this study was to comprehensively compare the influence of cross-sectional shape of ribbon arch wires with edgewise and round wires on intermaxillary traction in Class II malocclusion treatment using FEA simulation.MethodsThe dentofacial structure was simulated in finite element software. A retraction force of 1.5 N was applied to different cross-sectional orthodontic arch wires: a ribbon wire (0.025 × 0.017-in. and 0.025 × 0.019-in.), a rectangular wire (0.017 × 0.025-in. and 0.019 × 0.025-in.) and a round wire (Φ 0.018-in. and Φ 0.020-in.).ResultsAmong the three groups, ribbon wire (0.025 × 0.017-in. and 0.025 × 0.019-in.) exhibited the lowest displacement in the X-axis (12.61 μm and 12.77 μm, respectively) and Z-axis (8.99 μm and 9.06 μm, respectively). However, the 0.025 × 0.017-in. ribbon wire showed the highest Y-axis displacement. In the round wire group, Φ 0.020-in. wire displayed less rotation than Φ 0.018-in. wire, where the sagittal, frontal and occlusal rotation of Φ 0.020-in. wire was almost half of that of Φ 0.018-in. wire. The movement of the first molar region was intermediate between the ribbon arch group and the round wire group. Notably, the values of the 0.025 × 0.017-in. arch wire displacement, which were higher than those of any other group, peaked at 0.019 mm in the central incisor region with a spike-like shape. The deformation range of the Φ 0.018-in. wire group was the largest in this study.ConclusionsThe cross-section of the arch wire influenced force delivery in Class II intermaxillary traction. With the same shape, a larger cross-sectional area led to less mandibular dentition movement. For the rectangular arch wire and ribbon arch wire groups, since the height and width were inverted, the vertical displacement of anchorage teeth in the ribbon wire group was reduced, but the possibility of buccal tipping in mandibular anterior teeth also increased.

Experimental Investigation to Study the Feasibility of Fabricating Ultra-Conductive Copper Using a Hybrid Method.

Ultra-conductive copper (UCC) has an enormous potential to disrupt the existing electrical and electronic systems. Recent studies on carbon nanotubes (CNTs), a new class of materials, showed the ballistic conductance of electricity. Researchers around the world are able to demonstrate ultra-conductivity in micro- and millimeter-length sections using various processing techniques by embedding CNTs in the copper matrix. Although multiple methods promise the possibility of producing copper-based nanocomposites with gains in electrical conductivity, thus far, scaling up these results has been quite a challenge. We investigated a hybrid method of both hot-pressing followed by rolling in order to produce UCC wire. Cu/CNT billets of 1/10%, 1/15%, and 1/20% were hot-pressed and the conductivity results were compared to a hot-pressed pure copper billet. Our results indicated that this method is not a viable approach, as the gains in electrical conductivity are neutralized, followed by attenuation of the wire cross-section.

Effect of different media on frictional forces between tribological systems made from self-ligating brackets in combination with different stainless steel wire dimensions.

The purpose was to determine the effect of different environments (artificial saliva, human saliva, distilled water, dry storage) on frictional forces between various tribological systems made from self-ligating brackets in combination with stainless-steel wires (dimensions: 0.016″×0.022″, 0.018″×0.025″ and 0.019″×0.025″). An universal testing-machine applied a normal force of 1 N. Two-way ANOVA and Tukey post-hoc tests (α=5%) were used. Saliva had significantly higher frictional forces (p<0.001). Yet, the influence of the media depends on the wire dimensions. The results were not as straightforward as in 0.018″×0.025″, which had a clear order (dry storage<water<artificial saliva<human saliva, p<0.001 each). Except for human saliva, wire dimensions differed significantly from each other (p<0.001). Increasing wire cross-sections increases frictional force. Thus, saliva acts as adhesive. High frictional forces of larger wires are attributed to the contact between latch and wire. Still, in-vitro experiments can only approximate the quasi-static tooth movement and the various fluids in the mouth.

Guidelines for 3D printed springs using material extrusion

PurposeSprings are an integral part of mechanisms and can benefit from additive manufacturing’s (AM) increased design freedom. Given the limited literature on the subject, the purpose of this paper is to develop guidelines for fabricating helical springs using three-dimensional (3D) printing.Design/methodology/approachPolylactic acid (PLA) is the main material investigated, with ULTEM™ 9085 used as a comparison. The experimental procedure is to vary the spring parameters, print the springs and test them in tension or compression using constant velocity. Plots of the force and displacement are used to measure the linear and post-deformation spring constants. Loading of the springs is done both to breakage and cyclically. Cyclic loading is also used to observe the plastic behaviour of the springs. Parameters that are varied include wire and coil diameters, pitch, wire cross-section, in-fill and layer height.FindingsA square wire cross-section is used, instead of a circle because it produces more consistent coils. In-fills make no significant difference in the elastic stiffness of the springs but the mono in-fill breaks at a greater extension, so it is recommended. Tension and compression springs are confirmed to behave the same when in the elastic regime. ULTEM™ 9085 produces consistently weaker springs compared to PLA. Variation of layer height shows that thinner layers increase the stiffness of the springs.Originality/valueThis study investigates the behaviour of 3D printed helical springs in tension and compression. Three guidelines are created: square wire cross-section, mono-directional in-fill and thin layers are recommended.

Process design and finite element analysis of multi-station two-roller cassette hot rolling for aluminum alloy 6061 wire

In this paper, a round-oval-round roller cassette wire rolling process of the aluminum alloy 6061 was studied for the process and the roller design evaluation. The elliptic groove of roller was designed for the stand of oval cross-sectional profiles. The billet diameter for this 10- stand rolling process simulation is 20mm. The diameters for the round cross-section profile stands are 16mm,12.8mm,10.2mm,8.2mm, and 6mm, respectively. The forming conditions for the CAE simulation is 400 °C for billet temperature, 0.45 for the constant shear friction factor, 20mm/s for the initial rolling speed. The CAE (Computer Aided Engineering, CAE) results had shown the maximum dimension deviation of the billet is less than 0.25 mm at the location of the roller gap and almost perfect match at the other locations. The maximum principal stress distribution on the cross section had shown a two third area was deformed under the rolling process. The CAE results had demonstrated the proposed process and die design was able to make the smaller wire with good geometrical accuracy without breaking the wire during the rolling process because of the more uniform stress distribution at the cross section of wire.

Calculation Inductance of Toroidal Inductor Wound by Rectangular Cross-Sectional Wire

In this article, we present two methods for calculation of the inductance of toroidal inductor wound by rectangular cross-sectional wire, considering that the current density is inversely proportional to the circular coil radius. The first method is to simplify the helical toroidal coil into a thick-walled toroidal, and based on Grover’s toroidal inductor formula, the inductance is obtained by calculation the magnetic flux and the calculation method is simple, but the applicability is poor. The second method is to simplify the helical toroidal coil into a collection of self-closing circular coils, the calculation method is complex but has high accuracy, and the mutual inductance between the circular coils is calculated by the filament method based on the adjusted Grover’s mutual inductance of circular coils with inclined axes. We verify the adjusted Grover’s mutual inductance of filamentary circular coils with inclined axes and the mutual inductance between inclined circular coils with a rectangular cross section. Finally, we compared and analyzed the results calculated by the two methods proposed in this article and the results calculated by the finite element method.

Modelling the stiffness of plastic springs manufactured via additive manufacturing

The helical spring is one of the most used components in mechanisms but there is little research on the application of 3D printing, also called Additive Manufacturing, to springs. Therefore, the objective of this paper is to derive a model for the stiffness of 3D printed springs. The equation assumes that springs are made of orthotropic material and with a rectangular wire cross-section, that is, die springs. A second version of the equation has also been postulated that accounts for the misalignment of the deposited tracks with respect to the direction of the coils due to the coil pitch. The two models are compared to various springs printed with PLA and ULTEM 9085 and are found to accurately predict the stiffness of real, 3D printed springs. These equations allow the design and manufacturing of helical die springs for applications with few load cycles and that require chemical and radiation resistance, such as in space. The equations are also the first step in the development of models for new kinds of springs, such as linear conical springs or hollow wire die springs.