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Showing papers on "Spherical shell published in 2014"


Journal ArticleDOI
Ömer Civalek1
TL;DR: In this article, nonlinear static and dynamic responses of shallow spherical shells resting on Winkler-Pasternak elastic foundations are carried out, where the nonlinear governing equations of motion of shallow shells are discretized in space and time domains using the discrete singular convolution and the differential quadrature methods, respectively.

94 citations


Journal ArticleDOI
Shiqiang Li1, Zhihua Wang1, Guiying Wu1, Longmao Zhao1, Xin Li1 
TL;DR: In this article, the deformation of spherical shells, the energy absorption of each core layer, and the propagation characteristic of stress waves in the foam core layers were analyzed and discussed.
Abstract: Finite element simulations were conducted to investigate the dynamic responses of metallic sandwich spherical shells with graded aluminum foam cores under inner blast loading. The deformation of spherical shells, the energy absorption of each core layer, and the propagation characteristic of stress waves in the foam core layers were analyzed and discussed. The spherical shells exhibited an overall inflation–deformation mode as the foam cores were compressed gradually. The arrangement of the core layers with different relative densities had significant effects on the dynamic plastic responses of the spherical shells. The core layer arrangements of 15%–20%–10% and 20%–15%–10% (relative densities) from inside to outside demonstrate the optimal resistance to blast loading.

80 citations


Journal ArticleDOI
TL;DR: In this article, a numerical model of heat transfer and fluid flow during melting of a phase change material (PCM) inside a closed and uniformly heated spherical shell has been developed to investigate the thermal performance of the system.

71 citations


Journal ArticleDOI
TL;DR: In this article, a 3D free vibration analysis of multilayered structures is proposed based on a layer-wise approach, the continuity of displacements and transverse shear/normal stresses is imposed at the interfaces between the layers of the structures.
Abstract: A 3D free vibration analysis of multilayered structures is proposed. An exact solution is developed for the differential equations of equilibrium written in general orthogonal curvilinear coordinates. The equations consider a geometry for shells without simplifications and allow the analysis of spherical shell panels, cylindrical shell panels, cylindrical closed shells and plates. The method is based on a layer-wise approach, the continuity of displacements and transverse shear/normal stresses is imposed at the interfaces between the layers of the structures. Results are given for multilayered composite and sandwich plates and shells. A free vibration analysis is proposed for a number of vibration modes, thickness ratios, imposed wave numbers, geometries and multilayer configurations embedding isotropic and orthotropic composite materials. These results can also be used as reference solutions for plate and shell 2D models developed for the analysis of multilayered structures.

67 citations


Journal ArticleDOI
TL;DR: In this paper, the authors explored the occurrence of the spherical shell closures for superheavy nuclei in the framework of the relativistic Hartree-Fock-Bogoliubov (RHFB) theory.

65 citations


Journal ArticleDOI
TL;DR: In this paper, the first community activity to compare numerical results of computer codes designed to calculate fluid flow within a whole sphere was reported, and the first two benchmarks are defined based on uniform internal heating within the sphere under the Boussinesq approximation with boundary conditions that are uniform in temperature and stress-free for the flow.
Abstract: Convection in planetary cores can generate fluid flow and magnetic fields, and a number of sophisticated codes exist to simulate the dynamic behaviour of such systems. We report on the first community activity to compare numerical results of computer codes designed to calculate fluid flow within a whole sphere. The flows are incompressible and rapidly rotating and the forcing of the flow is either due to thermal convection or due to moving boundaries. All problems defined have solutions that allow easy comparison, since they are either steady, slowly drifting or perfectly periodic. The first two benchmarks are defined based on uniform internal heating within the sphere under the Boussinesq approximation with boundary conditions that are uniform in temperature and stress-free for the flow. Benchmark 1 is purely hydrodynamic, and has a drifting solution. Benchmark 2 is a magnetohydrodynamic benchmark that can generate oscillatory, purely periodic, flows and magnetic fields. In contrast, Benchmark 3 is a hydrodynamic rotating bubble benchmark using no slip boundary conditions that has a stationary solution. Results from a variety of types of code are reported, including codes that are fully spectral (based on spherical harmonic expansions in angular coordinates and polynomial expansions in radius), mixed spectral and finite difference, finite volume, finite element and also a mixed Fourier–finite element code. There is good agreement between codes. It is found that in Benchmarks 1 and 2, the approximation of a whole sphere problem by a domain that is a spherical shell (a sphere possessing an inner core) does not represent an adequate approximation to the system, since the results differ from whole sphere results.

59 citations


Journal ArticleDOI
TL;DR: In this article, the free vibration of laminated functionally graded (FG) spherical shells with general boundary conditions and arbitrary geometric parameters is studied based on the three-dimensional shell theory of elasticity and the energy based Rayleigh-Ritz procedure.

58 citations


Journal ArticleDOI
TL;DR: In this article, the authors extended the Kirchhoff-love shell theory to thin shell/membrane structures, which allows for finite membrane stretching as well as large deflection and bending strain.

56 citations


Journal ArticleDOI
TL;DR: In this article, a unified accurate solution procedure for free vibration analysis of arbitrary functionally graded spherical shell segments with general end restraints is presented, where the material properties of the spherical shells are assumed to change continuously in the thickness direction and two different four-parameter power-law distributions are considered.

53 citations


Journal ArticleDOI
TL;DR: In this article, the authors proposed a metamaterial made of an anisotropic and heterogeneous medium described by an elasticity tensor, which has 21 non-zero spatially varying coefficients in spherical coordinates.
Abstract: We propose a cloak for coupled shear and pressure waves in solids. Its elastic properties are deduced from a geometric transform that retains the form of Navier equations. The spherical shell is made of an anisotropic and heterogeneous medium described by an elasticity tensor ℂ′ (without the minor symmetries), which has 21 non-zero spatially varying coefficients in spherical coordinates. Although some entries of ℂ′, e.g., some with a radial subscript, and the density (a scalar radial function) vanish on the inner boundary of the cloak, this metamaterial exhibits less singularities than its cylindrical counterpart studied in [M. Brun, S. Guenneau, and A. B. Movchan, Appl. Phys. Lett. 94, 061903 (2009).] In the latter work, ℂ′ suffered some infinite entries, unlike in our case. Finite element computations confirm that elastic waves are smoothly bent around a spherical void.

49 citations


Journal ArticleDOI
TL;DR: In this article, a nonlinear thermo electro elastic analysis of a thick spherical shell for the functionally graded piezoelectric materials is presented, where the assumed structure is loaded under thermal, electrical and mechanical loads.

Journal ArticleDOI
TL;DR: In this article, a three-dimensional elastic analysis of the free vibration problem of one-layered spherical, cylindrical, and flat panels is proposed, and the exact solution is developed for the differential equations of equilibrium written in orthogonal curvilinear coordinates for the free vibrations of simply supported structures.
Abstract: The paper proposes a three-dimensional elastic analysis of the free vibration problem of one-layered spherical, cylindrical, and flat panels. The exact solution is developed for the differential equations of equilibrium written in orthogonal curvilinear coordinates for the free vibrations of simply supported structures. These equations consider an exact geometry for shells without simplifications. The main novelty is the possibility of a general formulation for different geometries. The equations written in general orthogonal curvilinear coordinates allow the analysis of spherical shell panels and they automatically degenerate into cylindrical shell panel, cylindrical closed shell, and plate cases. Results are proposed for isotropic and orthotropic structures. An exhaustive overview is given of the vibration modes for a number of thickness ratios, imposed wave numbers, geometries, embedded materials, and angles of orthotropy. These results can also be used as reference solutions to validate two-dimensional models for plates and shells in both analytical and numerical form (e.g., closed solutions, finite element method, differential quadrature method, and global collocation method).

Journal ArticleDOI
TL;DR: In this article, the Euler- Jacobi-Lie theorem was applied to the problem of free motion of a bundle of two bodies connected by means of a nonholonomic hinge.
Abstract: In this paper we investigate two systems consisting of a spherical shell rolling without slipping on a plane and a moving rigid body fixed inside the shell by means of two different mechanisms. In the former case the rigid body is attached to the center of the ball on a spherical hinge. We show an isomorphism between the equations of motion for the inner body with those for the ball moving on a smooth plane. In the latter case the rigid body is fixed by means of a nonholonomic hinge. Equations of motion for this system have been obtained and new integrable cases found. A special feature of the set of tensor invariants of this system is that it leads to the Euler — Jacobi — Lie theorem, which is a new integration mechanism in nonholonomic mechanics. We also consider the problem of free motion of a bundle of two bodies connected by means of a nonholonomic hinge. For this system, integrable cases and various tensor invariants are found.

Journal ArticleDOI
TL;DR: In this article, the authors compare numerical results of several different types of computer codes that are capable of solving the equations of momentum transfer, magnetic field generation and heat transfer in the setting of a spherical shell, namely a sphere containing an inner core.
Abstract: SUMMARY It is frequently considered that many planetary magnetic fields originate as a result of convection within planetary cores. Buoyancy forces responsible for driving the convection generate a fluid flow that is able to induce magnetic fields; numerous sophisticated computer codes are able to simulate the dynamic behaviour of such systems. This paper reports the results of a community activity aimed at comparing numerical results of several different types of computer codes that are capable of solving the equations of momentum transfer, magnetic field generation and heat transfer in the setting of a spherical shell, namely a sphere containing an inner core. The electrically conducting fluid is incompressible and rapidly rotating and the forcing of the flow is thermal convection under the Boussinesq approximation. We follow the original specifications and results reported in Harder & Hansen to construct a specific benchmark in which the boundaries of the fluid are taken to be impenetrable, non-slip and isothermal, with the added boundary condition for the magnetic field B that the field must be entirely radial there; this type of boundary condition for B is frequently referred to as ‘pseudovacuum’. This latter condition should be compared with the more frequently used insulating boundary condition. This benchmark is so-defined in order that computer codes based on local methods, such as finite element, finite volume or finite differences, can handle the boundary condition with ease. The defined benchmark, governed by specific choices of the Roberts, magnetic Rossby, Rayleigh and Ekman numbers, possesses a simple solution that is steady in an azimuthally drifting frame of reference, thus allowing easy comparison among results. Results from a variety of types of code are reported, including codes that are fully spectral (based on spherical harmonic expansions in angular coordinates and polynomial expansions in radius), mixed spectral and finite difference, finite volume, finite element and also a mixed Fourier-finite element code. There is good agreement among codes.

Journal ArticleDOI
TL;DR: In this paper, the authors proposed a cloak for coupled shear and pressure waves in solids, which is made of an anisotropic and heterogeneous medium described by an elasticity tensor.
Abstract: We propose a cloak for coupled shear and pressure waves in solids. Its elastic properties are deduced from a geometric transform that retains the form of Navier equations. The spherical shell is made of an anisotropic and heterogeneous medium described by an elasticity tensor C' (without the minor symmetries) which has 21 non-zero spatially varying coefficients in spherical coordinates. Although some entries of C, e.g. some with a radial subscript, and the density (a scalar radial function) vanish on the inner boundary of the cloak, this metamaterial exhibits less singularities than its cylindrical counterpart studied in [M. Brun, S. Guenneau, A.B. Movchan, Appl. Phys. Lett. 94, 061903 (2009).] In the latter work, C' suffered some infinite entries, unlike in our case. Finite element computations confirm that elastic waves are smoothly detoured around a spherical void without reflection.

Journal ArticleDOI
TL;DR: In this paper, the authors numerically explore the different instabilities emerging for rotation rates up to, venturing also into the nonlinear regime where oscillatory and chaotic solutions are found.
Abstract: The spherical Couette system is a spherical shell filled with a viscous fluid. Flows are driven by the differential rotation between the inner and the outer boundary that rotate with and about a common axis. This setup has been proposed for second-generation dynamo experiments. We numerically explore the different instabilities emerging for rotation rates up to , venturing also into the nonlinear regime where oscillatory and chaotic solutions are found. The results provide a comprehensive overview of the possible flow regimes. For low values of viscosity dominates and an equatorial jet in meridional circulation and zonal flow develops that becomes unstable as the differential rotation is increased beyond a critical value. For intermediate and an inner boundary rotating slower than the outer one, new double-roll and helical instabilities are found. For large values Coriolis effects enforce a nearly two-dimensional fundamental flow where a Stewartson shear layer develops at the tangent cylinder. This shear layer is the source of nearly geostrophic non-axisymmetric instabilities that resemble columnar Rossby modes. At first, the instabilities differ significantly depending on whether the inner boundary rotates faster or slower than the outer one. For very large outer boundary rotation rates, however, both instabilities once more become comparable. Fast inertial waves similar to those observed in recent spherical Couette experiments prevail for larger values and in when and are of comparable magnitude. For larger differential rotations , however, the equatorial jet instability always takes over.

Journal ArticleDOI
TL;DR: In this article, the authors experimentally observed heat diffusion transparency with a self-made heat diffusion device, which can measure time-dependent temperature using the effective medium theory and showed that the temperature gradients are parallel and equal outside the neutral inclusions.
Abstract: In this Letter, we experimentally observed heat diffusion transparency with the heat diffusion device we fabricated, which can measure time-dependent temperature Utilizing the effective medium theory, we fabricated an isotropic spherical shell with an isotropic spherical core, as well as a multilayer isotropic spherical shell with an isotropic spherical core as neutral inclusions We measured the temperatures and temperature gradients outside the neutral inclusions with the self-made heat diffusion device and analyzed the heat transparent conditions The experimental results show that the temperature gradients are parallel and equal outside the neutral inclusion, and the iso-temperature lines are also parallel outside the neutral inclusion

Journal ArticleDOI
TL;DR: In this article, the nonlinear free vibration behavior of laminated composite shallow shell under uniform temperature load is investigated and the midplane kinematics of the laminated shell is evaluated based on higher order shear deformation theory to count the out of plane shear stresses and strains accurately.
Abstract: In this article, nonlinear free vibration behavior of laminated composite shallow shell under uniform temperature load is investigated. The mid-plane kinematics of the laminated shell is evaluated based on higher order shear deformation theory to count the out of plane shear stresses and strains accurately. The nonlinearity in geometry is taken in Green-Lagrange sense due to the thermal load. In addition to that, all the nonlinear higher order terms are taken in the mathematical model to capture the original flexure of laminated panel. A nonlinear finite element model is proposed to discretise the developed model and the governing equations are derived using Hamilton’s principle. The sets of governing equations are solved using a direct iterative method. In order to validate the model, the results are compared with the available published literature and the limitations of the existing models have been discussed. Finally, some numerical experimentation has been done using the developed nonlinear model for different parameters (thickness ratio, curvature ratio, modular ratio, support condition, lamination scheme, amplitude ratio and thermal expansion coefficient) and their effects on the responses are discussed in detail.

Journal ArticleDOI
TL;DR: In this paper, the authors developed piezo-thermo-elastic analysis of a thick spherical shell for generalized functionally graded piezoelectric material, where the assumed structure is loaded under thermal, electrical and mechanical loads.
Abstract: The present paper develops piezo-thermo-elastic analysis of a thick spherical shell for generalized functionally graded piezoelectric material. The assumed structure is loaded under thermal, electrical and mechanical loads. The mechanical, thermal and electrical properties are graded along the radial direction based on a power function with three different non homogenous indexes. Primarily, the non homogenous heat transfer equation is solved by applying the general boundary conditions, individually. Substitution of stress, strain, electrical displacement and material properties in equilibrium and Maxwell equations present two non homogenous differential equation of order two. The main objective of the present study is to improve the relations between mechanical and electrical loads in hollow spherical shells especially for functionally graded piezoelectric materials. The obtained results can evaluate the effect of every non homogenous parameter on the mechanical and electrical components.

Journal ArticleDOI
TL;DR: In this paper, the authors studied axisymmetric gravito-inertial modes in the radiative zone of a differentially rotating star, where the star is a linearly stratified rotating fluid within a spherical shell, with differential rotation due to baroclinic effects.
Abstract: While many intermediate- and high-mass main sequence stars are rapidly and differentially rotating, the effects of rotation on oscillation modes are poorly known. In this communication we present a first study of axisymmetric gravito-inertial modes in the radiative zone of a differentially rotating star. We consider a simplified model where the radiative zone of the star is a linearly stratified rotating fluid within a spherical shell, with differential rotation due to baroclinic effects. We solve the eigenvalue problem with high-resolution spectral computations and determine the propagation domain of the waves through the theory of characteristics. We explore the propagation properties of two kinds of modes: those that can propagate in the entire shell and those that are restricted to a subdomain. Some of the modes that we find concentrate kinetic energy around short-period shear layers known as attractors. We describe various geometries for the propagation domains, conditioning the surface visibility of the corresponding modes.

Journal ArticleDOI
TL;DR: In this paper, the theory of nonlinear electroelasticity is used to examine radial deformations of a thick-walled spherical shell of soft dielectric material with compliant electrodes on its inner and outer surfaces combined with an internal pressure.

Journal ArticleDOI
TL;DR: In this paper, an exhaustive study based on numerical three-dimensional simulations of the Boussinesq thermal convection of a fluid confined in a rotating spherical shell is presented.

Journal ArticleDOI
TL;DR: In this paper, a full-field solution for the linear elasto-static problem of a homogeneous infinite Kirchhoff plate with a semi-infinite rectilinear crack resting on a two-parameter elastic foundation is presented.
Abstract: This paper presents a full-field solution for the linear elasto-static problem of a homogeneous infinite Kirchhoff plate with a semi-infinite rectilinear crack resting on a two-parameter elastic foundation. The same model describes the problem of a plate equi-biaxially loaded in its mid-plane by a constant normal force and, as a limiting case, the problem of a spherical shell. The full-field solution is obtained in closed form through the Wiener–Hopf method in terms of Fourier integrals. The stress-intensity factor (SIF) for the case of symmetric ( K 1 ) and skew-symmetric ( K 2 ) loading conditions is obtained and the role of the soil parameters is discussed. In particular, it is shown that a purely local model (Winkler) is unable to provide a safe-proof design limit.

Journal ArticleDOI
TL;DR: In this article, the authors considered the electrostatic problem of excitation of a homogeneous axisymmetric particle in a constant electric field and derived the expansion coefficients from infinite systems of linear algebraic equations (ISLAE).
Abstract: The electrostatic problem of excitation of a homogeneous axisymmetric particle in a constant electric field is considered. The approach is based on the surface integral equations arising in the extended boundary condition method (EBCM). The electrostatic fields are related to the scalar potentials, which are represented as expansions in the eigenfunctions of the Laplace operator in the spherical coordinate system. Unknown expansion coefficients are determined from infinite systems of linear algebraic equations (ISLAE). Analytic analysis of the solvability of the ISLAE is performed, and the convergence radii of expansions are obtained. It is shown that the EBCM can be applied in the far zone of a particle, i.e., the T matrix, can be constructed even if the Rayleigh hypothesis (the expansions converge up to the boundary of the particle) is not satisfied. However, a weaker restriction appears, which can be reduced to the requirement that there exists a spherical shell inside which the expansions of excited and internal fields simultaneously converge. The case of spheroids, as well as pseudospheroids that arise from spheroidal particles by inversion, is studied in detail. It is shown that the EBCM is applicable to spheroids for any ratio a/b of semiaxes and to pseudospheroids for a/b < 1 + \(\sqrt 2 \). The external Rayleigh hypothesis, i.e., the convergence of the expansion of a “scattered” field up to the surface of a particle is valid for a spheroid if a/b < \(\sqrt 2 \). The internal hypothesis, i.e., the convergence of an internal field, is always valid because the field is uniform inside the spheroid. For a pseudospheroid, the hypotheses are valid for a/b < \(\sqrt 2 \) and a/b < \(\sqrt 2 \), respectively. The relation and similarity between the results obtained for the wave and electrostatic problems are discussed.

Journal ArticleDOI
TL;DR: In this article, the authors proposed two ad hoc algorithms: (i) an explicit integration scheme based on a forward Euler technique with a center-of-mass return correction and (ii) an implicit integration scheme using a cutoff-substepping return algorithm.
Abstract: Inelastic deformation of ceramic powders (and of a broad class of rock-like and granular materials), can be described with the yield function proposed by Bigoni and Piccolroaz (2004. Yield criteria for quasibrittle and frictional materials. Int J Solids Struct, 41:2855–78). This yield function is not defined outside the yield locus, so that ‘gradient-based’ integration algorithms of elastoplasticity cannot be directly employed. Therefore, we propose two ad hoc algorithms: (i) an explicit integration scheme based on a forward Euler technique with a ‘centre-of-mass’ return correction and (ii) an implicit integration scheme based on a ‘cutoff-substepping’ return algorithm. Iso-error maps and comparisons of the results provided by the two algorithms with two exact solutions (the compaction of a ceramic powder against a rigid spherical cup and the expansion of a thick spherical shell made up of a green body), show that both the proposed algorithms perform correctly and accurately.

Patent
08 Oct 2014
TL;DR: In this article, a spherical modular autonomous robotic traveler (SMART) is provided for delivering a payload along a surface from a first position to a second position, which includes an outer spherical shell for rolling along the surface, an inner spherical chamber within the outer shell to carry the payload, a plurality of weight shifters arranged in the inner chamber, and a controller to activate a select weight shifter among the plurality.
Abstract: A spherical modular autonomous robotic traveler (SMART) is provided for delivering a payload along a surface from a first position to a second position. The SMART includes an outer spherical shell for rolling along the surface, an inner spherical chamber within the outer shell to carry the payload, a plurality of weight-shifters arranged in the inner chamber, and a controller to activate a select weight-shifter among the plurality. The weight-shifters can be arranged symmetrically or asymmetrically. The outer shell rolls in a direction that corresponds to the activated weight-shifter by torque induced thereby. The inner chamber maintains its orientation relative to the surface, even while the outer shell rolls along the surface. Each weight-shifter includes a channel containing an armature and an electromagnet activated by the controller. For the symmetrical arrangement, the channel is oriented from bottom periphery to lateral radial periphery of the inner chamber. The electromagnet is disposed proximal to the channel at the lateral radial periphery. The armature travels from the bottom periphery within the channel to the lateral radial periphery upon activation of the electromagnet.

Journal ArticleDOI
TL;DR: In this article, the Laplace transformation has been used to solve the problem of heat conduction with fractional order generalized thermoelasticity in a homogeneous visco-elastic orthotropic spherical shell.
Abstract: This problem deals with the thermo-elastic interaction due to step input of temperature on the stress free boundaries of a homogeneous visco-elastic orthotropic spherical shell in the context of a new consideration of heat conduction with fractional order generalized thermoelasticity. Using the Laplace transformation, the fundamental equations have been expressed in the form of a vector-matrix differential equation which is then solved by eigen value approach and operator theory analysis. The inversion of the transformed solution is carried out by applying a method of Bellman et al (1966). Numerical estimates for thermophysical quantities are obtained for copper like material for weak, normal and strong conductivity and have been depicted graphically to estimate the effects of the fractional order parameter. Comparisons of the results for different theories (TEWED (GN-III), three-phase-lag model) have also been presented and the effect of viscosity is also shown. When the material is isotropic and outer radius of the hollow sphere tends to infinity, the corresponding results agree with that of existing literature.

Journal ArticleDOI
TL;DR: In this paper, a finite element method has been applied to analyze free vibration problems of laminated composite stiffened shallow spherical shell panels with cutouts employing the eight-noded curved quadratic isoparametric element for shell with a three noded beam element for stiffener formulation.

Journal ArticleDOI
TL;DR: In this paper, the authors considered the problem of finding a non-collinear equilibrium solution for a rigid spherical shell with two primary bodies, one inside the shell and the other outside the shell.
Abstract: In this problem, one of the primaries of mass $m^{*}_{1}$ is a rigid spherical shell filled with a homogeneous incompressible fluid of density ρ1. The smaller primary of mass m2 is an oblate body outside the shell. The third and the fourth bodies (of mass m3 and m4 respectively) are small solid spheres of density ρ3 and ρ4 respectively inside the shell, with the assumption that the mass and the radius of the third and the fourth body are infinitesimal. We assume that m2 is describing a circle around $m^{*}_{1}$ . The masses m3 and m4 mutually attract each other, do not influence the motions of $m^{*}_{1}$ and m2 but are influenced by them. We also assume that masses m3 and m4 are moving in the plane of motion of mass m2. In the paper, equilibrium solutions of m3 and m4 and their linear stability are analyzed. There are two collinear equilibrium solutions for the system. The non collinear equilibrium solutions exist only when ρ3=ρ4. There exist an infinite number of non collinear equilibrium solutions of the system, provided they lie inside the spherical shell. In a system where the primaries are considered as earth-moon and m3,m4 as submarines, the collinear equilibrium solutions thus obtained are unstable for the mass parameters μ,μ3,μ4 and oblateness factor A. In this particular case there are no non-collinear equilibrium solutions of the system.

Patent
10 Sep 2014
TL;DR: In this article, an underwater spherical robot for shallow water detection is described, which consists of a pressure-proof sealing spherical shell structure, assistant propellers, a main propeller, an inner control device, a taper pedestal, a camera device and a sealing strip.
Abstract: An underwater spherical robot for shallow water detection is disclosed. The robot comprises a pressure-proof sealing spherical shell structure, assistant propellers, a main propeller, an inner control device, a taper pedestal, a camera device and a sealing strip. The pressure-proof sealing spherical shell structure is formed by sealing two semicircular spherical shells with the sealing strip. The four assistant propellers are fixedly installed outside the pressure-proof sealing spherical shell structure, and are evenly distributed at the hemisphere cross section. The main propeller is fixedly installed at the bottom of the pressure-proof sealing spherical shell structure. The installation axis of the main propeller is perpendicular to the installation axis of the assistant propellers and passes through the centre of sphere. The taper pedestal is fixedly installed at the bottom of the pressure-proof sealing spherical shell structure. The camera device is installed on an inner platform of the pressure-proof sealing spherical shell structure. The robot is good in integral pressure-proof effects, conform to hydromechanics, flexible and convenient for underwater movement and good in environmental suitability, and can be used as a detection device for shallow water detection that cannot be completed directly by humans.