Line Hinge Research Articles

Energy transfer and vibration suppression of laminated composite plates coupled with a line hinge

This study investigates the vibration energy flow transmission behavior of laminated composite plate structures coupled with a line hinge. The time-averaged vibration energy transfer is determined using the substructure-based power flow analysis (SPFA) method. The effects of the fiber orientation, boundary conditions and the position of the coupling hinge on the vibration transmission path and its level are examined. It is demonstrated that the fiber orientations can be used to modify substantially the power flow transmission path and locations of energy sinks. Enhancement of vibration suppression of the coupled structure can be achieved by tailor designing the fiber angles.

A variational approach to vibrations of laminated composite plates with a line hinge

A Ritz variational approach for the analysis of free vibration of plates with internal hinges distributed along a straight line is presented. The plate is modeled with the first order shear deformation theory and symmetric stacking sequences. The line with hinges is modeled by using subdomain decomposition of the plate coupled with penalty techniques, which causes an increment of the variational statement to assure the continuity conditions along the contact boundary of the plate's subdomains. In order to obtain an indication of the accuracy of the developed mathematical model and the proposed technique, some cases available in the literature have been considered. Original results are presented for solution of representative symmetric multilayered plates showing the effects of the line hinge parameters on the natural frequencies and mode shapes.

Natural vibrations of anisotropic plates with an internal curve with hinges

The objective of this paper is to propose a general algorithm to obtain approximate analytical solutions for the study of the free vibrations of a rectangular anisotropic thin plate with an internal curved line hinge and general restraints. In this system, there exists an intermediate condition that requires the continuity of the transverse displacements. It is well known that the difficulty in choosing admissible functions has been the most significant drawback of the Ritz method. To relax the admissibility requirement the Ritz method, with polynomials as coordinate functions, in conjunction with the Penalty Function method is proposed. This study is focus on different problems related the curved hinge and a natural parametrization is used to treat the mentioned curves. The accuracy of the formulation is ensured by comparing some numerical examples with those available in the literature. Cases not previously treated are particularly analyzed. Frequencies parameters and several sets of vibration mode shapes are included, to provide a better understanding of the dynamical behavior of these plates.

Free vibrations of a trapezoidal plate with an internal line hinge.

This paper deals with a general variational formulation for the determination of natural frequencies and mode shapes of free vibrations of laminated thin plates of trapezoidal shape with an internal line hinge restrained against rotation. The analysis was carried out by using the kinematics corresponding to the classical laminated plate theory (CLPT). The eigenvalue problem is obtained by employing a combination of the Ritz method and the Lagrange multipliers method. The domain of the plate is transformed into a rectangular domain in the computational space by using nonorthogonal triangular coordinates and the transverse displacements are approximated with a set of simple polynomials automatically generated and expressed in the triangular coordinates. The developed algorithm allows obtaining approximate analytical solutions for mentioned plate with different geometries, aspect ratio, position of the line hinge, and boundary conditions including translational and rotational elastically restrained edges. It allows studying the influence of the mentioned line on the vibration frequencies and respective mode shapes. The algorithm can easily be programmed and it is numerically stable. Additionally, as a particular case, the results of triangular plates can be easily generated.

A Simplified Model for Explosion Venting Due to the Separation of a Heavy Protective Cover

The paper presents a study aiming at simulation and understanding of some characteristics of an interior explosion within a room with an opening, that is initially being closed by a heavy cover, and may open gradually due to the effect of the explosion products. An effective simplified model of explosion venting due to separation of the protective cover has been developed. The developed model with lumped parameters is based on the Bernoulli equation and describes the quasi-stationary phase of the vented interior explosion. The initial internal gas pressure induced by the very short non-stationary phase is predicted by the developed approximate analytical formula, based on the full energy conservation law. The formula yields very good agreement with experimental data and with numerical analysis results. The simulation of the unsteady outflow from a cylindrical high-pressure vessel upon a sudden separation of the cover has shown that the developed simplified model yields the integral characteristics of the outflow process (such as a maximum cover's velocity and displacement etc) with reasonable accuracy. The proposed approach is demonstrated by the simulation of gas outflow from a chamber upon a sudden separation of the cover or upon a rectangular shutter rotation about a fixed line hinge. The analysis has been performed using the developed simplified approach and through simulations with AUTODYN. A good correspondence between both methods has been obtained. The effect of gravity on the protective cover velocity and displacement has been also examined.

Free vibrations of a generally restrained rectangular plate with an internal line hinge

This paper deals with the study of free transverse vibrations of rectangular plates with an internal line hinge and elastically restrained boundaries. The equations of motion and its associated boundary and transition conditions are rigorously derived using Hamilton’s principle. The governing eigenvalue equation is solved employing a combination of the Ritz method and the Lagrange multipliers method. The deflections of the plate and the Lagrange multipliers are approximated by polynomials as coordinate functions. The developed algorithm allows obtaining approximate solutions for plates with different aspect ratios, boundary conditions, including edges elastically restrained by both translational and rotational springs, and arbitrary locations of the line hinge. Therefore, a unified algorithm has been implemented. Sets of parametric studies are performed and the results are given in graphical and tabular form.

Boundary value problems for anisotropic plates with internal line hinges

This paper deals with the formulation of an analytical model for the dynamic behavior of anisotropic plates, with an arbitrarily located internal line hinge with elastic supports and piecewise smooth boundaries elastically restrained against rotation and translation among other complicating effects. The equations of motion and its associated boundary and transition conditions are derived using Hamilton’s principle. By introducing an adequate change of variables, the energies that correspond to the different elastic restraints are handled in a general framework. The concept of transition conditions and the determination of the analytical expressions are presented. Analytical examples are worked out to illustrate the range of applications of the developed analytical model. One of the essential features of this work is to demonstrate how the commonly formal derivations used in the applications of the calculus of variations can be made rigorous.

A simplified model with lumped parameters for explosion venting simulation

The paper presents a study aiming at simulation of some characteristics of an interior explosion within a room with an opening, that is initially closed by a heavy cover, and is gradually opened due to the pressures exerted by the explosion products. An effective simplified model of explosion venting due to separation of the protective cover has been developed. The developed model with lumped parameters is based on the Bernoulli equation and describes the quasi-stationary venting phase of the interior explosion. The initial internal gas pressure induced by the very short non-stationary phase is predicted by the developed approximate analytical formula, based on the full energy conservation law. The formula yields very good agreement with experimental data and with numerical analysis results. The simulation of the unsteady outflow from a cylindrical high-pressure vessel upon a sudden separation of the cover has shown that the developed simplified model yields the integral characteristics of the outflow process (such as a maximum cover’s velocity and displacement etc.) with reasonable accuracy. The proposed approach is demonstrated by the simulation of gas outflow from a chamber upon a sudden separation of the cover or upon a rectangular shutter rotation about a fixed line hinge. The analysis has been performed using the developed simplified approach and through simulations with AUTODYN. A good correspondence between both methods has been obtained. The effect of gravity on the protective cover velocity and displacement has been also examined.

Blast Wave Effects from Internal Explosion of Subsurface Explosive Storage Facility

To reduce safe distance such as inhabited building distance (IBD), a new type magazine, which is referred to as a subsurface magazine, has been proposed and the explosion effects have been discussed. We have conducted explosive tests by using relatively large scale models (23 kg and 78 kg in mass) and examined mass effect (scale effect) of blast waves caused by explosion of high explosives. The magazines were composed of a arch-type explosive storage room with a line hinge along the top of the roof of the wall, a square passage way to ground which will release the blast wave. Explosion hazards from the explosion of subsurface magazines were collected to understand the characteristics of airblast, fragments, and ground shocks. Safety criteria for the subsurface magazine are discussed based on the experimental results.

Effects of pH on growth development of larva Coelomactra antiquata and survival rate of fertilized eggs.

The effects of pH on the hatching of Coelomactra antiquata fertilized eggs and on the development as well as attachment metamorphosis of velige larva were studied.The results showed that the optimal pH for fertilized eggs to be hatched to trochophore larva was 7.0~8.5,while the optimal pH for trochophore larva to grow to straight line hinge larva was 7.5~8.5.Velige grew faster when pH was 8.0~8.2 and the average daily growth gain of shell length was 15.0~16.5 μm on average.When water temperature was 26.4±0.45 ℃,salinity 25.50 and pH 8.0~8.2,C.antiquata veliger with an average shell length of 196 μm,after 72 hours of cultivation,reached attachment metamorphosis at a rate of 51.66%~53.00%.

Natural vibration study on rectangular plates with a line hinge and various boundary conditions

A discrete method is proposed for analyzing the natural vibration problem of rectangular plates with a line hinge. The fundamental differential equations and the solutions of these equations are derived for two parts of the plate, which are obtained by dividing the plate along the line hinge. By transforming these equations into integral equations, and using numerical integration and the continuous conditions along the line hinge, the solutions of the whole plate can be expressed by the unknown quantities on the boundary and the quantities of the rotation along the hinge. The Green function of the deflection problem is used to obtain the characteristic equation of the free vibration. The effects of the position of the line hinge, the aspect ratio, the thickness ratio and the boundary condition on the natural frequency parameters are considered. By comparing the numerical results obtained by the present method with those previously published, the efficiency and accuracy of the present method are investigated.

A STUDY ON END FAILURES IN CORRUGATED STEEL SHEAR DIAPHRAGMS

Tests on shear corrugated steel plates were carried out to examine effect of shape and thickness of cross section on end failure action that may occur at the ends of flutes in shear diaphragms. Based on the test result and observation obtained through this research, previous deformation model for stiffness estimation were reviewed, and the deformation model were developed into strength model with application of yield line hinge. Strength design formulas were derived from the strength model using a limit analysis technique. Comparison with the test results showed that the derived formulas provided appropriate stiffness and strength estimation.

Free vibration analysis of shear deformable rectangular plates with a line hinge

A discrete method is proposed for analysing the natural vibration problem of shear deformable rectangular plates with a line hinge. The fundamental differential equations and the solutions of these equations are derived for two parts of the plate, which are obtained by dividing the plate along the line hinge. By transforming these equations into integral equations, and using numerical integration and the continuous conditions along the line hinge, the solutions of the whole plate can be expressed by the unknown quantities on the boundary and the quantities of the rotation along the hinge. Green function which is the solution of deflection of the bending problem of plate is used to obtain the characteristic equation of the free vibration. The effects of the position of the line hinge, the aspect ratio, the thickness-to-length ratio and the boundary condition on the natural frequency parameters are considered. By comparing the numerical results obtained by the present method with those previously published, the efficiency and accuracy of the present method are investigated.

Ritz Buckling Analysis of Rectangular Plates with Internal Hinge

This paper presents the Ritz method for buckling analysis of rectangular plates with an internal line hinge. The Ritz method involves the domain decomposition method to cater for the discontinuity of slope at the hinge line. The correctness of the Ritz formulation and solutions is confirmed by the exact solutions derived using the Levy method for plates with two opposite sides simply supported. Based on the Ritz method, buckling factors are generated for rectangular plates of various aspect ratios, hinge locations, and support and loading conditions.

Natural vibration of rectangular plates with an internal line hinge using the first order shear deformation plate theory

This paper presents exact solutions for vibration of rectangular plates with an internal line hinge. The rectangular plate is simply supported on two parallel edges and the remaining two edges may take any combination of support conditions. The line hinge is perpendicular to the two simply supported parallel edges. The Lévy type solution method and the state-space technique are employed in connection with the first order shear deformation plate theory (FSDT) to study natural vibration of rectangular plates with an internal line hinge. In particular, exact vibration frequencies are obtained for rectangular plates of different aspect ratios and edge support conditions. The influence of the internal line hinge on the vibration behavior of rectangular plates is studied.

BUCKLING AND VIBRATION OF ORTHOTROPIC PLATES WITH AN INTERNAL LINE HINGE

This paper presents the exact buckling loads and vibration frequencies of orthotropic rectangular plates with internal line hinge and having two opposite edges simply supported while the other two edges may have any combination of free, simply supported, and clamped conditions. An analytical method that uses the Lévy solution method and the domain decomposition technique is employed to determine the buckling loads and natural frequencies of rectangular plates with internal line hinge.