scholarly journals Transient Dynamic Analysis of a Cantilever Rod with Axial Impulse Loading Using Finite Element Method

2018 ◽  
Vol 202 ◽  
pp. 02005
Author(s):  
Sushmita Deka ◽  
Pallekonda Ramesh Babu ◽  
Maneswar Rahang
Keyword(s):  
Cross Section ◽  
Circular Cross Section ◽  
Fem Analysis ◽  
Axial Direction ◽  
The Body ◽  
Impulse Loading ◽  
Transient Dynamic Analysis ◽  
Impulse Load ◽  
Cantilever Rod ◽  
Impulse Force

The behavior of bodies subjected to impulse loading is of prime importance in the study of forces that occur in impulse facilities. Before performing the actual tests, theoretical and numerical simulations are carried out to obtain the response of bodies subjected to impulse loading. The simplest model for this study can be considered as a rod of circular cross section fixed at one end and free at other end. When a transient impulse load is applied on a body, vibrations occur in the body for the brief period of time. In this paper, the effect of a half sine impulse force applied on a cantilever rod in the axial direction has been discussed. The displacements at the tip of the rod were obtained based on two theories, the basic vibration formulae and FEM analysis. Simulations were performed using ANSYS and compared with the displacements obtained from the two theoretical methods.

The Structure and Function of the Basement Membrane Muscle System in Amphiporus lactifloreus (Nemertea)

1952 ◽  
Vol s3-93 (21) ◽  
pp. 1-15
Author(s):  
J. B. COWEY
Keyword(s):  
Basement Membrane ◽  
Cross Section ◽  
Circular Cross Section ◽  
The Body ◽  
Minimum Length ◽  
Muscle Fibres ◽  
Body Volume ◽  
Cross Sectional ◽  
Elliptical Cross ◽  
Sectional Shape

The body wall of A. lactifloreus has the following structure from the outside inwards. (i) A basement membrane of five to six layers immediately underlying the epithelium. Each layer consists of right-hand and left-hand geodesic fibres making a lattice, whose constituent parallelograms have a side length of from 5 to 6µ. The fibres are attached to one another where they cross; so there can be no slipping relative to one another. (ii) A layer of circular muscle-fibres running round the animal containing two systems of argyrophil fibres--one of fibres at intervals of 10µ. running parallel to the muscle-fibres and the other of fibres running radially through the layer from the basement membrane to the myoseptum. (iii) A myoseptum which is identical in structure with a single layer of the basement membrane (iv) A layer of longitudinal muscle, whose fibres are arranged in layers on each side of a series of longitudinal radial membranes. Membranes identical in structure with the basement membrane invest the nerve cords, the gut, the gonads, and the proboscis. The interrelations of argyrophil and muscle-fibres in the muscle layers is described and their functioning discussed. The system of inextensible geodesic fibres is analysed from a functional standpoint. The maximum volume enclosed by a cylindrical element (cross-section circular), of such a length that the geodesic makes one complete turn round it, varies with the value of the angle θ between the fibres and the longitudinal axis. When θ is 0° the volume is zero; it increases to a maximum when θ is 54° 44' and decreases again to zero when θ is 90°. The length of the element under these conditions varies from zero when θ is 90° to a maximum (the length of one turn of the geodesic) when θ is 0°. The body-volume of the worm is constant. Thus it has a maximum and minimum length when its cross-section is circular, and at any length between these values its cross-section becomes more or less elliptical. It is maximally elliptical when θ is 54° 44', i.e. when the volume the system could contain, at circular cross-section, is maximal. From measurements of the ratio of major to minor axes of this maximally elliptical cross-section, the maximum and minimum lengths of the worm relative to the relaxed length and values of θ at maximum and minimum length are calculated. The worm is actually unable to contract till its cross-section is circular; but measurements of its cross-sectional shape at the minimum length it can attain, permit calculation of the theoretical length and value of θ for this cross-sectional shape. Calculated values of length and the angle 6 agree well with the directly observed values.

The transmission of surface waves under surface obstacles

1961 ◽  
Vol 57 (3) ◽  
pp. 638-668 ◽  
Author(s):  
F. Ursell
Keyword(s):  
Free Surface ◽  
Surface Waves ◽  
Transmission Coefficient ◽  
Cross Section ◽  
Water Waves ◽  
Wave Train ◽  
Circular Cross Section ◽  
Great Distance ◽  
The Body ◽  
Radius Of Curvature

ABSTRACTA train of surface waves (water waves under gravity) is normally incident on a cylinder with horizontal generators fixed near the free surface, and is partially transmitted and partially reflected. At a great distance behind the cylinder the wave motion tends to a regular wave train travelling towards infinity; the ratio of its amplitude to the amplitude of the incident wave is the transmission coefficient . The transmission coefficient is studied when the wavelength is short compared to the dimensions of the body; physically (though not for engineering applications) this is the most interesting range of wavelengths, which corresponds to the range of shadow formation and ray propagation in optics and acoustics. The waves are then confined to a thin layer near the free surface, and the transmission under a partially immersed obstacle is then small. In the calculation the boundary condition at the free surface is linearized, viscosity is neglected, and the motion is assumed to be irrotational.At present the transmission coefficient is known only for a few configurations, all of them relating to infinitely thin plane barriers. A method is now given which is applicable to cylinders of finite cross-section and which is worked out in detail for a half-immersed cylinder of circular cross-section. The solution of the problem is made to depend on the solution of an integral equation which is solved by iteration. Only the first two terms can be obtained with any accuracy, and it appears at first that this is not sufficient to give the leading term in the transmission coefficient at short wavelengths; this difficulty is characteristic of transmission problems. By various mathematical devices which throw light on the mechanism of wave transmission, it is, nevertheless, found possible to prove that the transmission coefficient for waves of short wavelength λ and period 2π/ω incident on a half-immersed circular cylinder of radius a is asymptotically given bywhen N = 2πα/λ = ω2α/g is large. Earlier evidence had pointed towards an exponential law. It is suggested that transmission coefficients of order N−4 are typical for obstacles having vertical tangents and finite non-zero radius of curvature at the points where they meet the horizontal mean free surface. For obstacles having both front and rear face plane vertical to a depth a, is probably of order e−2N approximately; if only one of the two faces is plane vertical, is probably of order e−N approximately. Thus is seen to depend critically on the details of the cross-section.

The mechanisms of boring in Martesia striata Linné (Bivalvia: Pholadidae) and Xylophaga dorsalis Turton (Bivalvia: Xylophaginidae)

1969 ◽  
Vol 174 (1034) ◽  
pp. 123-133 ◽  
Keyword(s):  
Cross Section ◽  
Circular Cross Section ◽  
Mantle Cavity ◽  
Body Fluids ◽  
The Body ◽  
Clockwise Rotation ◽  
Faecal Pellets ◽  
Adductor Muscles ◽  
Inhalant Siphon ◽  
Wood Boring

Penetration of timber by the wood-boring bivalves Martesia striata and Xylophaga dorsalis is effected by means of the cyclical repetition of a group of movements termed the boring cycle. In Martesia the boring cycle comprises first the retraction of the shell to the base of the burrow, followed by the abrasion of the wall of the burrow by movements of the shell caused by a single consecutive contraction of each of the adductor muscles. In Xylophaga similar movements are involved, but the boring cycle in this species has become elaborated by repetition of the contractions of the adductor muscles which may be repeated to give a series of up to 24 rocking movements of the shell about a dorso-ventral axis. In both species the boring cycle may be followed by movements involving anti-clockwise and clockwise rotation in the burrow, while simultaneously the siphons are partially withdrawn and re-extended; in both, longer term rotations in the burrow result in the production of a drop-shaped burrow of circular cross-section. In both species the material abraded from the base of the burrow is collected into the mantle cavity; in Martesia it is then ejected as pseudofaeces through the inhalant siphon at intervals during boring, while in Xylophaga a larger proportion passes into the gut and eventually collects in the form of faecal pellets to form a plug to the burrow. The pressures developed in the mantle cavity and haemocoele during boring are small compared to those in burrowing forms, but of the same order as those recorded from the related rock-boring pholad Zirphaea crispata , and it is concluded that the body fluids play a decreasing hydraulic role as specialization for boring increases.

Natural Convection Heat Transfer From Long Horizontal Isothermal Cylinders

1994 ◽  
Vol 116 (1) ◽  
pp. 96-104 ◽  
Author(s):  
S. B. Clemes ◽  
K. G. T. Hollands ◽  
A. P. Brunger
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Cross Section ◽  
Body Height ◽  
Convection Heat Transfer ◽  
Circular Cross Section ◽  
Correlation Equation ◽  
The Body ◽  
Natural Convection Heat Transfer ◽  
Convection Heat

A new set of measurements is reported on natural convection heat transfer in air from isothermal long horizontal cylinders of noncircular cross section at various orientations, covering the Rayleigh number (Ra) range from about 103 to about 109. The data are correlated reasonably well by a conduction layer model with a constant value (i.e., the same for all body shapes and orientations) of 5.42 for the Churchill-Usagi coefficient blending the laminar and turbulent asymptotes. The resulting correlation equation normally requires only the geometric specification of the body height and perimeter. This model is also tested against data in the literature on the subject problem, and found to be generally predictive, to within about ±10 percent. A new set of data covering the same Ra range is also reported for the circular cross-section case, i.e., the long horizontal isothermal circular cylinder. Comparison of this data with the several existing correlations for this well-known problems shows that the Kuehn and Goldstein equation predicts the data best, although the Raithby and Hollands equation also predicts the data very well, but only after a revision to the blending coefficient.

Numerical Calculations of the Hypersonic Viscid–Inviscid Flow Inside Simple Ducts of Circular Cross-Section

1971 ◽  
Vol 22 (3) ◽  
pp. 233-256 ◽  
Author(s):  
B. H. K. Lee
Keyword(s):  
Cross Section ◽  
Circular Cross Section ◽  
Internal Flow ◽  
Wave Interaction ◽  
Inviscid Flow ◽  
The Body ◽  
Constant Wall Temperature ◽  
Reflected Shock ◽  
Displacement Thickness ◽  
High Mach

SummaryThe method of characteristics and an implicit finite-difference scheme are used to investigate the interaction between the internal flow field and laminar boundary layer in ducts of circular cross-section under the conditions of high Mach number and low Reynolds number. The displacement thickness is added on to the body to form a new “effective body shape” which is used to re-calculate the inviscid flow. Iterations are performed and a solution is obtained when the surface pressures in two consecutive iterations converge to within a specified tolerance. The calculated surface pressures on a 10 degree conical duct placed in a hypersonic stream at M∞=8·34, Re∞=7·5 × 106 and M∞=10·4, Re∞=4·625 × 106 with γ=1·4 show good agreement with experiments. The results are computed for constant wall temperature, using a value of Tw/Tstag=0·23, and the Prandtl number is assumed to be constant and equal to 0·7 throughout the calculations. The type of shock-wave interaction near the axis of symmetry is determined and the computation terminates after the fluid properties behind the reflected shock have been calculated.

scholarly journals Diffraction of a plane wave by an almost circular cylinder

1961 ◽  
Vol 264 (1317) ◽  
pp. 246-268 ◽  
Keyword(s):  
Plane Wave ◽  
Cross Section ◽  
Circular Cross Section ◽  
The Body ◽  
Maximum Deviation ◽  
Dimensional Problem ◽  
Plane Wave Incident ◽  
Method Of Solution ◽  
Watson Transformation ◽  
The Mean

The two-dimensional problem of an E-polarized plane wave incident on a perfectly conducting cylinder of almost circular cross-section is treated , the maximum deviation of the perimeter of the cross-section from a strict circle being regarded mathematically as an infinitesimal quantity whose second and higher powers are neglected. In the body of the paper the method of solution uses infinite Fourier transform techniques, but an analysis involving a Watson transformation, more traditional in this type of problem , is given in appendix A. Attention is for the most part directed to the case in which the mean radius of the cylinder is large compared to the wavelength, and the form of the solution then appropriate is examined in some detail. In particular, initial terms of asymptotic expansions in inverse powers of the mean radius to wavelength ratio are obtained for the ‘specular’ and for the ‘creeping’ contributions to the far field. It is shown that the former contributionis in agreement with that derived by the Luneberg—Kline method, and the latter with the prescription proposed by Keller. Various Bessel function results are required, some of which are derived in appendices.

Experimental Tensile Tests on Bone Cement: Effect of Test Sample Shape

2015 ◽  
Vol 665 ◽  
pp. 29-32
Author(s):  
Cristian Sorin Nes ◽  
Lucian Bogdan ◽  
Jenel Marian Patrascu
Keyword(s):  
Bone Cement ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Circular Cross Section ◽  
Tensile Tests ◽  
The Body ◽  
Sample Shape ◽  
Cross Section Area ◽  
Section Area ◽  
Shape And Size

Objectives: The mechanical characteristics of bone cement depend on the chemical composition, mixing technique, polymerization period and temperature. Additionally, the shape of the cement mantle can also lead to variations in the mechanical properties of the material, as thicker walls are significantly more non-homogeneous and less permeable for the body fluids. This paper presents experimental tensile tests on bone cement focused on the study of the influence of the test specimen shape on the obtained results.Methods: High viscosity bone cement, produced and supplied as polymer powder and monomer liquid portions was used. The mixed cement was inserted during the working time into two types of silicon molds: one with the shape and size according to ISO 527 (“dogbone” shape with rectangular cross section area) and other with the shape and size according to ASTM F 2118 (“dogbone” shape with circular cross section area). Both types of test specimens have approximately the same value of the cross sectional gauge area. All samples were polished with grit abrasive paper in the longitudinal direction and soaked in phosphate buffered saline (PBS) solution. The specimens were subjected to a tensile test on a hydraulic machine. To avoid the occurrence of critical stress areas on the specimen, special fixing devices were manufactured.Results and conclusions: The stress–strain curves of all specimens tested exhibited similar linear elastic regime followed by brittle fracture. However, different values of the ultimate tensile strength and elastic modulus of tested samples were recorded.

SAF file: It's really three dimensional file

2018 ◽  
Vol 14 (1) ◽  
pp. 1
Author(s):  
Prof. Dr. Jamal Aziz Mehdi
Keyword(s):  
Cross Section ◽  
Root Canal ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Circular Motion ◽  
Root Canal Treatment ◽  
Metal Core ◽  
Rotating Blade

The biological objectives of root canal treatment have not changed over the recentdecades, but the methods to attain these goals have been greatly modified. Theintroduction of NiTi rotary files represents a major leap in the development ofendodontic instruments, with a wide variety of sophisticated instruments presentlyavailable (1, 2).Whatever their modification or improvement, all of these instruments have onething in common: they consist of a metal core with some type of rotating blade thatmachines the canal with a circular motion using flutes to carry the dentin chips anddebris coronally. Consequently, all rotary NiTi files will machine the root canal to acylindrical bore with a circular cross-section if the clinician applies them in a strictboring manner

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