Thin-walled Cylinder Research Articles

Strength design of tubular textile composites for pipeline rehabilitation under internal pressure

The tubular textile composite material is lined on the inner wall of the pipeline by the inversion method, and realizes the structural or semi-structural repair of the pipeline in the form of “pipe in pipe”. Under the action of inversion pressure and working internal pressure, its strength directly affects the repair effect. In this paper, the pressure in the process of inversion and conveying medium is discussed, using theories such as the thin-walled cylinder theory and Hooke's law to analyse the stress of composite materials under internal pressure of the pipeline, and strength calculation equations used in the structural or semi-structural repair are established. The strength design was carried out by taking drainage pipes as an example. The results show that in the structural repair pipeline, and there is a certain value in the range of pipe diameter 1200–1400 mm. When the pipe diameter is before a certain value, the strength of tubular textile composites is designed according to the stress generated by working internal pressure. After a certain value, the strength is designed according to inversion pressure. Moreover, in the semi-structural repair pipeline, the stress under working pressure is far less than that under inversion pressure, so the strength of the material is designed according to inversion pressure.

Numerical Study of Tube Hydroforming Process Using Conical Dies

In this paper the effect of die angle, fluid pressure and axial force on loading paths were studied. In order to reduce the cost and time for the experimental work, ANSYS program is used for implementing the Finite Element Method (FEM), to get optimized loading paths to form a tube using double – cones shape die. Three double die angles θ (116˚ 126˚, 136˚), with three different values of tube outer diametres (40, 45, 50) mm were used. The tube length L_o and thickness t_o for all samples were 80 mm and 2 mm respectively.
 The most important results and conclusions that have been reached that had the highest wall thinning percentage of 26.8% with less corner filling is at tube diameter 40 mm and cone angle of (116^°) at forming pressure of 43 MPa with axial feeding 10 mm. However, the lowest wall thinning percentage was 6.9% with best corner filling at diameter 50 mm and cone were angle of (136^°) and forming pressure of 30 MPa with axial feeding 4.5 mm. Two wrinkles constituted during the initial stages of forming the tube with initial diameter of 40 mm where the ratio d⁄(t=20) (thick-walled tubes) for all die angles, while only one wrinkle is formed at the center for tubes diameter 45 and 50 mm (thin-walled tubes) . The difference in the location and number of wrinkles at the first stage of formation depends on the loading paths that has been chosen for each process, which was at the diameter 45 and 50 mm towards thin-wall cylinder deformation mode was uniaxial tension. The maximum wall thinning percentage was at the bulge apex for tube diameter 40 mm. But, the maximum wall thinning for tubes of diameters 45 and 50 mm was found at the two sides of the bulge apex .

Research and Application of Flutter Suppression Technology for Aeroengine Case Machining

The magazine is an important part of the aero-engine, its main role is to bear the load and mass inertia force generated by the engine in the work. The design and manufacturing level of the magazine is of great significance to improve the aero-engine’s quality. Engine magazine belongs to a thin-wall cylinder part with large size, complex shape and high processing precision. Due to its thin wall rigidity difference, the processing quality is easy to reduce caused by the vibration of machine tools and other processing system, and cannot meet the requirements. According to the absorption principle of TMD (Tuning Mass Damper), an auxiliary fixture is designed to transfer the magazine processing vibration energy to the auxiliary fixture to reduce the vibration of the processing system and to improve the processing quality. Through ANSYS analysis, the maximum vibration amplitude of the magazine was reduced by 60% by using this fixture. Therefore, the fixture can significantly reduce the vibration in the processing and have good effect on improving the quality of the processing. The auxiliary fixture has the advantages of simple installation, simple disassembly, and strong scalability.

Deformation Analysis and Fixture Design of Thin-walled Cylinder in Drilling Process Based on TRIZ Theory

Thin-walled cylindrical workpiece is easy to deform during machining and clamping processes due to the insufficient rigidi. Moreover, it’s also difficult to ensure the perpendicularity of flange holes during drilling process. In this paper, the element birth and death technique is used to obtain the axial deformation of the hole through finite element simulation. The measured value of the perpendicularity of the hole was compared with the simulated value to verify then the rationality of the simulation model. To reduce the perpendicularity error of the hole in the drilling process, the theory of inventive principle solution (TRIZ) was used to analyze the drilling process of thin-walled cylinder, and the corresponding fixture was developed to adjust the supporting surface height adaptively. Three different fixture supporting layout schemes were used for numerical simulation of drilling process, and the maximum, average and standard deviation of the axial deformation of the flange holes and their maximum hole perpendicularity errors were comparatively analyzed, and the optimal arrangement was optimized. The results show that the proposed deformation control strategy can effectively improve the drilling deformation of thin-walled cylindrical workpiece, thereby significantly improving the machining quality of the parts.

Optimal design of integrated main supporting structure with ultra-light weight and high stability for space camera

To ensure excellent performance of a micro reflective space camera, an integrated main supporting structure (IMSS) combined with a thin-walled tube and a supporting rod structure design is applied in this study. Firstly, this paper covers the design and comparison of the performance of three traditional types of main supporting structures (MSS), including thin-walled cylinder type, rod-supporting type and truss type. Then, an IMSS combined with a thin-walled tube and a supporting rod structure is described. In addition, a multi-objective integrated optimization method which allows automatic modeling, analysis, calculation and optimization is proposed. Further, the influence of the supporting rod angle on the structure performance is studied, the performance of stiffness, deformation and mass is better when the height ratio of the rod-structure and the thin-walled cylinder is 6:1. The IMSS mass is only 0.56 kilograms, that is 11.2 % of the total mass of the payload, and the maximum deformation on the supporting bar is no more than 4.5 nm. Finally, the IMSS performance is analyzed by the finite element method and experimental verification, and the first order frequency is up to 192.7 Hz. The degree of light weight is significantly better than that of the traditional structures. The results of the experiment further prove the stability of the IMSS.

Phase solitons in a weakly coupled three-component superconductor

Based on the phenomenological Ginzburg-Landau approach, we investigate phase solitonic states in a class of three-component superconductors for mesoscopic doubly-connected geometry (thin-walled cylinder) in external magnetic fields. Analysis of the Gibbs free energy of the system shows that solitonic states in a three-component superconductor are thermodynamically metastable and separated from the ground state by a sizable energy. Our results demonstrate that despite of the presence of the zoo of phase solitons states earlier proposed method [Phys. Rev. B 96, 144513 (2017)] for the detection of BTRS in multiband superconductors remains valid and useful.

Localization and snaking in axially compressed and internally pressurized thin cylindrical shells

Abstract This paper uncovers new manifestations of the homoclinic snaking mechanism in the post-buckling regime of a pressurized thin cylindrical shell under axial load. These new forms tend to propagate either wholly or partially in a direction that is orthogonal to the direction of the applied load and so, unlike earlier forms in Woods & Champneys (1999, Heteroclinic tangles in the unfolding of a degenerate Hamiltonian Hopf bifurcation. Phys. D, 129, 147–170), are fundamentally 2D in nature. The main effect of internal pressurization on the snaking mechanism is firstly to transition the circumferential multiplication of buckles from a one-tier pattern to a three-tier pattern. Secondly, internal pressurization can induce oblique snaking, whereby the sequential multiplication of buckles occurs in a helical pattern across the cylinder domain. For low levels of internal pressure, the single dimple remains—as in the unpressurized case—the unstable edge state that forms the smallest energy barrier around the stable pre-buckling equilibrium. For greater levels of pressure, the edge state changes to a single dimple surrounded by four smaller dimples. By tracing the limit point that denotes the onset of these edge states in the parameter space of internal pressure and axial load, we justify and validate the empirically derived design guideline for buckling of pressurized cylinders proposed by Fung & Sechler (1957, Buckling of thin-walled circular cylinders under axial compression and internal pressure. J. Aeronaut. Sci., 24, 351–356).

More Precise Honing of Holes in Stepped Thin-Walled Cylinders

More Precise Honing of Holes in Stepped Thin-Walled Cylinders

Oscillation of a balanced hollow cylinder on an inclined plane

The static and dynamic properties of an asymmetric rigid body are studied using a Lagrangian approach. The body consists of a thin-walled cylinder balanced by a point mass attached to its inner surface. When resting on an inclined plane, stable and unstable equilibrium points are found, and oscillations about the stable point are studied for different angles of inclination and different values of the balancing mass. The analysis illustrates the utility of Lagrangian mechanics, and the derived results can be experimentally verified using simple materials.

Burst pressures of thin-walled cylinders constructed of steel exhibiting a yield plateau

The burst pressures of large diameter-to-thickness ratio thin-walled cylinders constructed of steel exhibiting a yield plateau were evaluated experimentally, by finite element analyses (FEA), and by existing predictive equations. The good agreement between the predicted and experimentally measured burst pressures of three thin-walled tanks with a large diameter-to-thickness ratio of 342, demonstrates that the proposed FEA model and failure criterion can evaluate the burst pressure of a thin-walled cylinder accurately. In contrast, a conventional elastic-strain hardening plasticity material model may overestimate the burst pressure of a cylinder. The results indicate that a nonlinear stabilization technique in ANSYS is a useful way to overcome the convergence difficulty caused by material softening when the FEA model includes the steel yield plateau. Comparisons of existing predictive models and experimental values reveal that most of the equations have a prediction deviation less than 10%, and that the Faupel equation can predict the burst pressure of a thin cylinder with high diameter-to-thickness ratio, with high precision.

Modelling of dimensional and geometric error prediction in turning of thin-walled components

In die-mold manufacturing and aircraft industry, many components that have thin-walled features are produced by turning operation. The major problem encountered during internal or external turning is cutting force induced deflection of workpiece along the periphery as well as axial length of a component. The present research work aims to develop a mathematical model for estimating dimensional and geometric errors during turning of thin-walled hollow cylinder qualitatively and quantitatively. In the proposed model, a mechanistic approach which is semi-analytical in nature is followed to achieve accuracy of the predicting results. First of all, process geometry model for thin-wall turning is developed based on process geometry variables such as uncut chip thickness, actual feed per revolution, actual depth of cut, peripheral cutting speed, effective cutting area etc. Using these process geometry variables and mechanistic cutting constants, a force model of turning is developed to estimate the tangential and radial force components. Later on, based on the predicted forces, tool-workpiece combined deflection model is developed to estimate radial, diametric and various geometric errors of the turned surface. The developed models are able to predict radial, diametric and various geometric errors such as straightness, circularly and cylindricity errors without conducting expensive actual machining operation. Hence, the present study will be helpful to take care of precautionary measures for controlling of dimensional and geometric errors more efficiently and reliably. Therefore, an attempt has been made to provide a basic platform to machining practitioners and process planners for in-depth comprehension and characterization of dimensional and geometric errors of the entire turned surface for varying machining conditions.

Про застосування титанової фольги в конструкціях паяних малогабаритних вікон для передачі променевої енергії

The aim of this work was to miniaturize the design of a brazed joint of a thin non-metallic disk with a hollow thin-walled metal cylinder for operation as part of a vacuum device in a wide temperature range. For brazing a non-metallic disk with a glass tube-shaped device body, when choosing a metal filler, the fragility of glass, its low mechanical strength in bending and tensile and a lower thermal coefficient of linear expansion than metal fillers must be taken into account. Therefore, the use of low-temperature plastic solders based on tin, indium, lead etc., which are alloyed with titanium, is preferable. However, the disadvantages of these fillers include a significant decrease in mechanical strength when the brazed unit is heated to relatively low temperatures, especially if there is a gas inside the device under excessive pressure. The option of brazing a leucosapphire disk with a glass tube was also considered. A design has been proposed to determine how a disk is connected to a titanium body. This design has increased the heat resistance of the leucosapphire lens, which is connected to the body of the product made of titanium alloy or covar. Such connection can be used as pyrometer windows installed directly in the body of an internal combustion engine or gas turbine engine. The main feature of this development was the creation of a brazed joint structure in which the shell covering the disk is made of non-metal, in this case of leucosapphire, made of titanium foil with a thickness of 100 and in some cases 50 μm. Brazing modes were set and brazed windows were made. Tests on the vacuum density after different modes of thermal cycling of brazed samples showed high performance of this structure of the brazed joint. It was shown that the use of titanium foil makes it possible to obtain high-quality heat-resistant brazed joints. The relatively small stresses that lead to plastic deformation of the foil make it possible to increase the inconsistency of the thermal coefficient of linear expansion (TCLE) of materials that were brazed. It shout be noted that the foil material can also be other metals which had chemical active towards non-metallic materials or their components, for example, zirconium, niobium, tantalum, etc. Keywords: structures of brazed joints, brazing of non-metals, non-metallic materials, leucosapphire, glass tube, adhesive-active filler metals, fillers, titanium.

Loss of atoms from a near-resonance hollow dipole trap

The lifetime of a gas of 6Li atoms in a large hollow optical dipole trap formed by radiation with a frequency detuned by 4 or 2 GHz upward from resonance is measured. The trap has the shape of a thin-walled cylinder with flat bases and a volume of ∼1 mm3. The main mechanism responsible for the loss of atoms is heating due to Rayleigh scattering. The influence of collisions of atoms with the background gas and with each other on the measured lifetime is negligible.

Simulation and Experiment of a Kind of Thin-Walled Tube Crushing Member Used for Antiimpact Column

In order to solve the problem of poor antiimpact ability of hydraulic support under rock bursting, a kind of thin-walled cylinder crushing component used in the composite spiral antiimpact device was developed, and different structural models were proposed and simulated. On this basis, the model was verified by experiments. The results show that the arrangement of the hollow structure can restrain the ring mode deformation and Euler instability of the tube member in the crushing yield and can carry out the buckling deformation according to the expected crushing force during the compression deformation process and effectively reduce the initial peak force. The arrangement of guide grooves can make the buckling deformation more stable and regular, which can effectively reduce the initial peak force and elastic displacement. With the smaller wall thickness and the smaller wall thickness of the induced groove, the effective deformation yield stroke of the crushing member increases, and the initial peak force, total energy absorption, average reaction force, and elastic displacement decrease. The simulation results are consistent with the experimental results which will be used in the future works.

Bulging initiation and propagation in fiber-reinforced swellable Mooney\u2013Rivlin membranes

This article considers a thin-walled hollow cylinder, which is composed of a fibrous and swellable hyperelastic material. The fibers are arranged in two families and they are taken to be parallel within each fiber family. The two fiber families are also assumed to be mechanically equivalent and symmetrically disposed in the ground substance material. At each instant of the homogeneous swelling, the material is taken to be incompressible. This article studies the interplay of swelling, fiber orientation, and the mechanical properties of the constituents on the initiation as well as on the axial propagation of bulging.

Mini-max optimization of actuator/sensor placement for flexural vibration control of a rotating thin-walled cylinder over a range of speeds

For a rotating thin-walled cylinder subject to flexural vibration, active control can be applied using surface-mounted actuators and sensors. To achieve acceptable vibration control performance, the dependency of the dynamic behaviour on rotational speed must be accounted for in the control system design, including the selection and positioning of actuators and sensors. A key issue is that the natural modes of vibration of the cylinder wall involve circumferential travelling waves and, for certain rotational speeds, the frequency of a backward wave for a low order mode can become equal to that of a forward wave for a high order mode. It is shown that these frequency-crossings have important implications for the actuator/sensor placement problem due to the potential for loss of controllability. Accordingly, an actuator/sensor placement approach is introduced based on a mini-max optimization, where the system controllability is maximized for the worst-case rotational speed within a specified interval. Placement solutions are obtained through the application of a nested particle swarm optimization algorithm, used to find saddle-point solutions. The approach is shown to be effective for cases involving 2, 3 and 4 actuator/sensor pairs and with multi-mode model (including up to 16 modes). The results are confirmed by experiments on a thin-walled rotor system with piezo patch actuators and sensors, where H2 control algorithms are applied to suppress vibrational resonances within a control bandwidth of 200-1200 Hz. The potential for loss of controllability at certain rotational speeds is confirmed, as well as the effectiveness of the optimal placement solutions in maintaining control performance over a targeted range of speeds.

In-plane asymmetric buckling of an FGM circular arch subjected to thermal and pressure fields

Several recent applications, i.e. space-structures and fusion reactors, involve the adoption of functionally graded materials (FGM) in their basic elements, such as the thin-walled cylinders, arches, beams, plates, and so on. These elements may be under a temperature variational environment due to the season's change, day and night temperature variation, or even fire disasters. The load capacity and/or buckling behavior of these thin-walled structures may be different from the ones only under mechanical loadings. Based on this fact, this study refers to the in-plane asymmetric buckling of the heated circular FGM arches under uniform pressure fields. The material of the FGM arch is thermo-elastic. A thermal radially-outward deflection occurs before the pressure field is introduced. This deflection may result in different buckling mechanisms from the arch under pure pressure loading. Analytical predictions on the buckling pressure are derived by combining the thin-walled shell schemes, admissible displacement functions, and the energy theory. Subsequently, a finite element simulation is introduced to trace the kinematic movement of the crown point. The pressure-displacement plots are obtained, from which, the buckling pressure is reachable. It is found the thermal field affects considerably the static stability of the FGM arch. Finally, a discussion refers mainly to the influence of material inhomogeneity on the buckling pressure, especially focusing on the influence of different power-law indexes on the internal forces, stresses, and strains.

Improving the honing accuracy of the holes of stepped thin-walled cylinders

Different ways of fixing of stepped thin-walled cylinders during honing are analyzed. The conditions for increasing the accuracy of hole machining are determined on the basis of unevenness of cylinder deformations from clamping forces and radial forces simulating cutting forces. The studies used the finite element method and the DEFORM-3D V6.1 software package. Keywords: honing, stepped thin-walled cylinder, hole, accuracy, fixing method, deformation, unevenness, DEFORM-3D V6.1 software package. ogorodov.va@inbox.ru

Experimental investigation of frost heave force on tubing and casing

Currently, CO2 injection is mainly used to rejuvenate oil reservoirs as a tertiary oil recovery technology. During the cryogenic CO2 injection process, when the temperature drops below the freezing point of water, the volume expansion caused by the freezing of the water in the tubing and casing annulus generates a frost heave force. This additional force increases the risk of tubing fracture and shortens the life of the well. Therefore, in this paper, a laboratory experiment is carried out to analyse the characteristics of tubing and casing stress under the effect of a frost heave force. The results show that the frost heave force in the annulus squeezes the tubing and casing into an ellipse during the freezing process and that the strength of the frost heave force is approximately equivalent to the internal pressure of 104 MPa in a thin-walled cylinder pressure vessel of the same size. The experimental results explain the tubing and casing failure mechanism with the effect of frost heave force and provide a theoretical basis for providing a solution to improve the service life of tubing and casing in a cryogenic CO2 injection well.

Application of UHMWPE in energy-absorbing road safety systems

The article considers the possibility of using a polymer material based on ultra-high molecular weight polyethylene (UHMWPE) in energy-absorbing structures of road safety systems. To determine the mechanical and energy absorbing characteristics of the material, bench tests carried out on the material and element of the designed structure in the form of a thin-walled cylinder. The possibility of using UHMWPE in the actual design of the road safety system checked by creating a validated digital twin of the impact attenuator. Based on the simulation results, polymer and metal structures compared.