Influence Of Plate Thickness Research Articles

Uji Beban dan Analisis Lendutan Model Pelat Fleksibel yang Didukung Tiang-Tiang pada Tanah Pasir

Sand commonly has a good bearing capacity. Problems may occur when sand has low density and thick deposit. Flexible plate foundation may be used in this soil but plate deflection may be still high. To reduce deflection and improving soil density, piles were used to support the plate. Installing piles made foundation system stiffer. The objectives of this study are to studies about behavior of plates and plate with a pile of sand on the ground, influence of plate thickness , pile length and spacing of the pole deflection, and the influence of the bond between the plate and the deflection of the pile .In this study is used test box of 1.2 m depth, 1.2 m width, 1.2 m length, and 1.0 m depth filled out with sand. Plate models were made from plexiglas of rectangular and square geometry. Piles were of steel pipesof 2.5cm diameter. Some parameters were as follows : plate thickness, plate geometry, pile length (L), pile spacing (s), bounding between plate and pile (fix or free), ’piled’ and freestanding foundation, and base pile enlargement. The behavior of the plateswere observed under loading (point load). The result shows that plate deflections were affected by the method of pile installation, plate thickness and pile length. For a ticker plate, contact surface between plate and soil was wider. For the 40cmx10cm plates with fix end pile, deflectionswere founf to reduced up to 70% compared with free end pile. The ’piled foundation’ on 40cmx10cm plates, L=20cm, s=4d, deflections were reduced 83,63% compared with free standing foundation.

Modeling and analysis of transient temperature field in finite thickness plate under symmetrically located moving heat sources

The thermal problem of plate slides against symmetrically located contacting pads is investigated. The aim is to find out the influences of plate thickness, moving speed, and convection on the temperature field of the plate. Proper models and computing methods for specific situations can be determined based on these analyses. Finite element method of moving heat input is used to calculate the temperature field which is validated by comparing with some existing analytical solutions. The results show that the characteristic time for the steady state of temperature can be approximated exponentially as a function of moving speed. If the plate is thinner than the critical thickness, the surface temperature is increased significantly, which means that the temperature field is very sensitive to the plate thickness in this situation. The increasing moving speed increases the peak surface temperature almost linearly, and the convection outside of the contact area can decrease the peak surface temperature significantly if the heat sources move slowly, while it hardly affects the peak surface temperature if the heat sources move fast. Based on these results, the criterion of choosing a model and computing methods for studying the temperature fields in the similar structures is established.

Fatigue behavior prediction of welded joints by using an integrated fracture mechanics approach

Current fracture mechanics methods for fatigue assessment of welded joints are based on long crack behavior. The present work introduces a method to predict the fatigue strength of welded joints by means of an integrated fracture mechanics approach (IFMA) that takes into account the fatigue behavior of short cracks. This methodology estimates the fatigue crack propagation rate as a function of the difference between the applied driving force and the material threshold for crack propagation, function of crack length. Firstly, the proposed fracture mechanic method is introduced and compared with the traditional fracture mechanic approach, used mainly for fitness for purpose assessment of welded joints with cracks or other crack-like defects. Then, the method is used for several theoretical and parametric applications to show its ability to predict the influence of different mechanical, geometrical and microstructural parameters in the definition of the fatigue resistance of welded joints. The influence of plate thickness, initial crack length and reinforcement angle on fatigue strength of butt-welded joints has been analysed and results show good agreement with experimental trends. Finally, the method is applied to predict and analyze the fatigue behavior of butt welded and non-load-carrying transverse fillet welded joints, and estimated and experimental results are analysed and compared.

Time-dependence in mantle convection models featuring dynamically evolving plates

SUMMARY We present the findings from a study of 2-D Cartesian geometry mantle convection simulations carried out to determine how plate velocities and the surface and basal heat flux respond to an evolving plate geometry. We model flow for periods equating to hundreds of millions of years and find that while calculations that feature fixed plate geometries exhibit regular reversals in plate motion, this behaviour is absent in models featuring evolving plate boundaries. However, simulations featuring evolving plate boundaries and plates with either a fixed-thickness or temporally varying thickness are highly time-dependent and their globally averaged mean plate velocities are higher than in simulations featuring static plate geometries. Our models featuring evolving plate geometries assume that (1) young plates override old plates with the velocity of the younger plate and (2) that symmetric seafloor spreading occurs at divergent plate boundaries. Plate velocities are dynamically determined in accord with a force-balance modelling approach and the plate velocities determine the dynamic evolution of the plate boundaries according to criteria (1) and (2), above. Plates in our calculations are highly viscous and are treated as rigid blocks for the purpose of determining whether they will break according to a yield stress criterion. The modelling of plate rifting means that both the number and mean size of the plates in our calculations are time-dependent. We focus on isolating the influence of plate thickness on time-dependent flows and examine the time-dependence of global plate velocities and mantle and core heat flow. In an initial study of unit aspect ratio models we find that there is a transition in the character of time-dependent behaviour as the model plate thickness is increased. Plates that are comparable in thickness to the mean thickness of the thermal boundary layer exhibit periodic reversals. Plates that are much thinner than the thermal boundary layer exhibit no reversals. Intermediate thickness plates reverse intermittently. In aspect ratio 12 calculations, we find that the mean global plate velocity can exhibit variations of more than a factor of two over periods of tens of millions of years. We also find that the mean surface velocity of the plates and the mean global heat flux rise and fall in tandem (although high frequency variations in the global velocity are not reflected in the heat flux time-series). In a simulation spanning almost 3 Gyr we observe several instances of surface heat flux fluctuations of 40–50 per cent occurring within periods of 75–200 Myr.

Efficient formulation for band-structure calculations of two-dimensional phononic-crystal plates

Based on Mindlin's plate theory and the plane wave expansion method, a formulation is proposed to study the propagation of Lamb waves in two-dimensional phononic-crystal plates. The method is applied to calculate the frequency band structure of a square array of crystalline gold cylinders in an epoxy matrix with a finite thickness. It is found that complete frequency band gaps for Lamb waves between different pass bands are opened up by tuning thickness of the phononic-crystal plate. The influence of plate thickness on the width of complete frequency band gap is calculated and discussed as well; the existence of frequency stop bands is sensitive to the variation of the thickness of the plate. Finally, we note that the proposed method provides a concise and efficient way in analyzing the frequency band structures of phononic-crystal plates in lower bands.

Integrated fracture mechanics approach to analyse fatigue behaviour of welded joints

Current fracture mechanics methods for fatigue assessment, including those that consider thresholds for crack propagation, are based on long crack behaviour. The present work is concerned with an attempt to predict the fatigue strength of welded joints using a fracture mechanics approach that takes into account the fatigue behaviour of short cracks. The methodology estimates the fatigue crack propagation rate as a function of the difference between the applied driving force and the material threshold for crack propagation, which is a function of crack length. The fatigue strength of butt welded specimens stressed transversely was analysed. Experimental results from the literature were used for comparison. Estimations are obtained by using only the fatigue limit and the fatigue propagation threshold for long cracks, and the applied stress distribution along the crack path obtained from simple finite element models. The influence of plate thickness, initial crack length, and reinforcement angle on fatigue strength of butt welded joints was analysed. Results show good agreement with experimental trends.

Influence of Plate Thickness on the Mechanical Properties of Welded Joints Subjected to Long-Term Postweld Heat Treatments

During their service lives, storage spheres, pressure vessels, and other welded structures are subjected frequently to postweld heat treatments (PWHT). Repeated treatments may result, in some cases, in a reduction in mechanical strength and fracture toughness of the weldments such that their mechanical properties may not meet the code specifications after those treatments. Steel ASTM-A-516 Gr 70 is used frequently to build storage spheres and pressure vessels in the petrochemical industry. In this context, the thickness of the plate is an important variable relative to the mechanical behavior of the welded joint after repeated PWHT. In a previous work (Pimenta and Bastian, JMEPEG, 2001, 10, pp. 192–202), the effect of the duration of a PWHT on the mechanical properties of a 65 mm thick plate was evaluated. In the present work, the effect of the same heat treatment on the properties of a 46.4 mm thick plate was evaluated and compared with those of the 65 mm thick plate. For this purpose, hardness measurements, tensile and Charpy V-notch impact tests, and a metallographic analysis were performed. The results show that both the base metal and heat-affected zone of the thinner plate present higher mechanical strength and impact resistance for all heat-treated conditions. The obtained mechanical properties were then compared with the requirements of the ASME Code, Section VIII.

Effect of Grazing Flow on the Acoustic Impedance of an Orifice

A linearized potential flow model is developed to study the effect of grazing flow on the acoustic behavior of an orifice. In accordance with the previous flow visualization and measurements, this model uses the particle velocity continuity boundary condition rather than the widely used displacement to match the flow-fields separated by the shear layer over the orifice. An experiment is also carried out to validate the present theory in the case of circular or rectangular orifices. The theory agrees well with the experiment. In addition, further comparison is made between the present and two existing impedance models. One major objective of the present investigation is to make a tentative judgement on the two boundary conditions for a sound wave transmitting through a turbulent boundary layer over an orifice. It is found that, compared to the particle displacement continuity boundary condition, the use of the particle velocity continuity boundary condition results in a much better agreement between the theoretical predictions and the experimental data. Finally, there is a discussion on the influence of plate thickness on orifice impedance in the presence of grazing flow.

Numerical Dynamic Analysis of Moving GTA Weld Pool

A three dimensional model with a moving heat source is developed to describe heat transfer and fluid flow in transient weld pools. Full penetration and free top and bottom surfaces are incorporated in the model in order to simulate the welding process more practically. The influence of plate thickness and welding current on the dynamics of weld pools is analyzed using calculated data. It is shown that when the workpiece is nearly penetrated, the depth of weld pool increases quickly. Also, the elevation of the top surface decreases quickly once the full penetration status is established.

すみ肉溶接継手の曲げ疲労強度に及ぼす板厚および残留応力の影響 : 荷重非伝達すみ肉溶接継手の曲げ疲労き裂の発生・進展に及ぼす板厚および残留応力の影響(第2報)

すみ肉溶接継手の曲げ疲労強度に及ぼす板厚および残留応力の影響 : 荷重非伝達すみ肉溶接継手の曲げ疲労き裂の発生・進展に及ぼす板厚および残留応力の影響(第2報)

Influence of Geometry and end Conditions on Optimal Fundamental Natural Frequencies of Symmetrically Laminated Plates

The fundamental natural frequency of rectangular symmetrically laminated plates with a given material system is maximized with respect to fiber orientations by using a sequential linear programming method together with a simple move-limit strategy. Significant influence of plate thickness, aspect ratio, circular cutout and end conditions on the optimal fiber orientations and the associated optimal fundamental natural frequency of fiber-reinforced laminated composite plates has been shown through this investigation.

Inhomogeneous plane-wave scattering and mode stimulation on periodic rough surfaces

Medium vibration properties to characterize interface layers and quality of bonding can be examined by an ordinary approach using homogeneous waves or by a more general inhomogeneous (or complex harmonic) wave scattering technique. It is known that only particular inhomogeneous plane waves can stimulate eigenvibrations of a given structure, and not the homogeneous wave. The reflection and transmission of such inhomogeneous waves is investigated for plane parallel interfaces as well as their scattering at periodically corrugated boundaries between liquid and solids. The influence of plate thickness, corrugation periodicity, and height on the occurrence of specific plate modes is examined. Using an alternative description of a bounded ultrasonic beam as a finite superposition of inhomogeneous waves, this theory can be applied to examine the deformation of Gaussian profiles and to explicitly relate this deformation to the stimulation of mode vibrations. The generation of a plate—or interface—mode by an obliquely incident single inhomogeneous wave on a plane parallel plate—or half-space interface boundary—and the scattering of inhomogeneous waves at the interface wave stimulated corrugated surface, also suggest a new interpretation of back reflection and transmission of bounded beams at smooth liquid–solid interfaces.

Three-dimensional vibration of rectangular plates: Effects of thickness and edge constraints

Abstract A continuum three-dimensional Ritz formulation is presented for the free vibration analysis of homogeneous, isotropic, thick, rectangular plates. The method is applied specifically to investigate the effects of boundary constraints and thickness ratios on the vibration responses of these plates. A general switching of transverse vibratory motions to surface-parallel modes at the higher thickness ratio is manifested vividly through three-dimensional deformed mode shape plots. The present formulation is based on the linear, three-dimensional, small-strain elasticity energy principle. In the solution process, sets of self-generating polynomial shape functions are used to derive the governing eigenvalue equation. In essence, these functions comprise a class of orthogonal polynomial functions and a basic function which is chosen to satisfy the essential geometric boundary conditions at the outset. They are found very suitable for the computationally intensive task of 3-D modelling due to the ease of generation and numerical implementation. Several numerical examples have been computed to demonstrate the accuracy and efficiency of the method. The influences of plate thickness and boundary constraints on the overall vibratory characteristics of thick plates are also discussed in detail.

荷重非伝達すみ肉溶接継手の疲労強度に及ぼす残留応力の影響

In this paper, the influence of plate thickness on the fatigue strength of non-load-carrying fillet weld joints is examined both experimentally and analytically, from the view point of weld residual stresses.In order to control the longitudinal residual stresses (in the direction of the weld line), rib-cruciform joint specimens with various plate width were prepared. On the one hand, specimens of which heat input for each pass was varied were also prepared to control the transverse residual stresses (in the perpendicular direction to the weld line). Using these specimens, both residual stress measurement and fatigue tests were carried out.It was found that the plate width of specimen had great effects on the longitudinal residual stresses and little effect on the transverse residual stresses respectively. And it was also found that the transverse residual stresses increased as the heat input decreased.As far as the heat input was constant, the plate width had no effect on the fatigue strength. On the other hand, the heat input significantly influenced the fatigue strength of joints with a same thickness of main plate. That was, the fatigue strength in the case of high heat input was much higher than in the case of low heat input.From above results, it is concluded that the fatigue strength of non-load-carrying fillet weld joints depends on the transverse residual stresses and that the tensile residual stresses increase as the plate thickness increases and/or the heat input decreases, causing the reduction of the fatigue strength.

Influence of plate thickness and heat input on fatigue strength of non-load-carrying fillet weld joints

In this paper, the influence of plate thickness on the fatigue strength of non-load-carrying fillet weld joints is discussed, from the viewpoint of the residual stress and the stress concentration.The calculation methods of the weld residual stresses in cruciform joints and T joints are presented, and the residual stresses are expressed in functions of plate thickness, yield strength, and heat input. The calculated residual stresses are compared with the experimental ones, and are in good agreement with.The combined effects of mean stresses (or of the stress ratio) and the weld residual stresses are applied to the fatigue strengthes of the cruciform joints and the T joints, and it is confirmed that the difference in the fatigue strength between the two types of joint is due to the difference of the residual stress distributions.In the last part of the paper, the estimation method on the fatigue strength of the non-load-carrying fillet weld joint is presented. By means of the method, the fatigue strength of the joint is estimated, with the fatigue strength of the base metal, the stress ratio, the stress concentration due to the joint, and the residual stress. On 67 sets of the test results, the applicability of the estimation method is confirmed.

Effect of base plate thickness on wave size and wave morphology in explosively welded couples

The influence of plate thickness on the wave morphology generated in explosive welding is analysed by the use of mild steel base plates machined into steps of different thicknesses and a constant-thickness mild steel flyer plate, to ensure similar impacting conditions. It is found that wave shape, at the same distance from the collision point, remains unchanged for the different thicknesses. However, wavelength and wave amplitude are observed to decrease for thinner base plates, while the incubation distance for stable wave generation is observed to increase with decreasing base plate thickness. Previously suggested mechanism for explosive wave generation are analysed in terms of the present experiments. It is apparent that most of the theories proposed to date for wave formation are in one way or another incomplete.

Contact problem of rubber rings with large deformation

A contact problem with friction between a rubber ring with large deformation and a linear elastic thin plate is solved by means of the substructuring technique in this paper. A study of the inf/uence of frictional contact, of the influence of plate thickness on rubber ring' deformation is presented.

Performance limits of primary and secondary batteries

Battery performance is a complicated compromise of many contrary demands in the fields of technology and economics. Further complications are introduced by the need for uniform quality, safe manufacture, etc. Thus, no single property can be regarded in isolation. Also, standards have to be met. A few examples will be given: matching of plates, influence of nonworking parts of the surface, influence of porosity, and influence of plate thickness.

Finite element analysis of stress intensity factors for plane extension and plate bending problems

AbstractThis paper deals with the finite element calculation of the stress intensity faactors for plane extension and plate bending problems. On the basis of the plate theory including the effect of transverse shear deformation, the influences of plate thickness, crack length and plate width on the stress intensity faotors are investigated. The numeriacal analyses are carried out using the superposition method of analytical and finite element solutions. It is found that the present stress intensity factors calculated for cracked plates under plane extension as well as bending compare favorably with the analytical ones.

Experimental study of magnetic forces on normal and null flux coil arrangements in the inductive levitation system

We report on measurements of lift and drag forces exerted by various small-scale current-carrying superconducting coils, placed near a large rotating disk. In detail we have studied the influences of shape and arrangement of the coils, as well as the influences of plate thickness, velocity and suspension height. In some experiments the drag force was measured under constant load condition. Most of the experimental results are compared with exact calculations based upon the general theory recently given by Miericke and Urankar [1] for infinitely wide but arbitrarily thick sheet tracks. The agreement between experiment and theory was generally good, and we believe that predictions for large-scale systems can be made with confidence.