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The theory is presented of the increase in damping that can be obtained when a damping compound is added to a simple structure vibrating in a bending mode. Consideration has been given to the use of ‘Aquaplas’ damping compound on a vibrating stringer‐skin combination, and it has been shown that the maximum damping ratio is obtained when the material is applied to the stringer flange over the centre 40 per cent of the pin‐ended length of the beam. A preliminary experimental investigation is described, in which damping measurements were made on a simple structural specimen treated with Aquaplas. A new method was used successfully to determine the damping ratio of a heavily damped system. The damping properties of Aquaplas were evaluated, and some of the theoretical conclusions were verified. Some of the results obtained indicate that a more accurate mathematical representation must be sought for the visco‐elastic behaviour of Aquaplas than is provided by the ‘complex stiffness’ method.

IN a previous paper, attention was called to the general behaviour of the vibratory system comprising the aeroplane‐engine‐airscrew combination. Types of vibration frequently encountered were described and a brief resumé of damping, excitation, and natural frequency effects was given. It is the purpose of this paper to review the general problem in light of current practice and to discuss in some detail certain observations made in the course of experimental study of the complete problem.

This paper is concerned with a new proposal regarding the analysis of visco‐elastoplasticity and fatigue and is based on rheological‐dynamical theory. Due to the analogy between rheological model and dynamical model with viscous damping, it becomes obvious that inelastic response of members is essentially a dynamical problem. An analytical rheological‐dynamical viscoelasto‐ plastic solution of one‐dimensional longitudinal continuous vibration under loading and solution for the stress relaxation as unloading have been developed and used to obtain the fatigue limit of thin long bars. Rheologic behavior of the bar can be characterized by one parameter, like in a single‐degree‐of‐freedom spring mass system. In all inelastic strains time rate effects are always present to some degree. Whether or not their exclusion has a significant influence on the prediction of the material fatigue behavior depends upon several factors like: maximum absolute stress in the cycle, coefficient of asymmetry of cycle, creep coefficient, slope of the strain hardening portion of the stress‐strain curve, relative frequency and uniaxial yield stress. This paper provides description of dynamic magnification factor, relaxation of stress, stress concentration and the fatigue limit of thin long symmetrical bars.

This paper deals with the experimental investigation and non‐linear finite element analysis of composite wing T‐joints in hygrothermal environments. This study is concerned with T‐joints subjected to tension (pull‐out) force and their behaviour up to ultimate failure under bone dry and hygrothermal environments. The behaviour of such joints is complex due to the geometry of the joint configuration and laminated construction. T‐joints are also susceptible when exposed to moisture and temperature environments. As a consequence, the stiffness and strength properties of laminates because degraded. A three‐dimensional 20‐noded multidirectional composite element is developed using three‐dimensional super element concept to analyse both unstitched and stitched T‐joints. All the stress components are computed and the failure loads are evaluated using different failure criteria to get better insight into the behaviour of laminated composite wing T‐joints.

The purpose of this manuscript is to study the vibration characteristics of the spherically symmetric solid and hollow spheres poised of a homogeneous thermoelastic material, based on the three dimensional coupled thermoelasticity.

In this paper, matrix Fröbenius series solution is used to derive the frequency equations, for the field functions. Results have been applied on rigidly fixed boundary conditions.

The main finding of this paper is that the frequency of vibration of spherically symmetric sphere (structure is independent of theta and phi) increases with the increase of radius, for solid spheres and for hollow spheres with thickness to mean radius ratio. Deformation in the given materials increases with thickness to mean radius ratio of the hollow sphere.

A numerical simulation has been done with the help of functional iteration method for solid and hollow thermoelastic spheres made of zinc and poly methyl meth acrylate materials for different boundary conditions. The computer simulated results in contempt of frequency, damping of vibration modes and displacement have been obtained graphically and compared with the existed results.

Describes the McKibben muscle and its major properties. Outlines the analogy between this artificial muscle and the skeletal muscle. Describes the actuator composed of two McKibben muscles set into antagonism based on the model of the biceps‐triceps system, and explains its natural compliance in analogy with our joint litheness. Reports some control experiments developed on a two d.o.f. robot actuated by McKibben muscles which emphasize the ability of these robot‐arms to move in contact with their environment as well as moving loads of high ratio to the robot’s own weight. Also outlines control difficulties and accuracy limitations and discusses applications.

The purpose of this paper is to study the method of hysteresis energy distribution and maximum relative lateral displacement in buildings’ stories, under the influence of scaled records for near-fault and far-fault earthquakes. The bracings in the considered buildings’ plan are distributed in two different ways: in the first case, the braces are added in external frames of the building, and in the second case, in the internal ones.

This research first selects some steel buildings with concentric braces and studies the seismic vulnerability of buildings under different earthquakes in accordance with the concepts of input and Hysteresis energy. In order to study the impact of braces’ distribution in the building’s plan, the buildings were modeled in this study in two ways. In the first way the braces were added to the building’s external frames and in the second way in its internal ones.

Results show that the need for far-fault scaled records’ displacement is more than the near ones and that the resultant relative lateral displacements in buildings with external braces are more than those with internal ones.

After these studies on the way of hysteresis energy distribution, it was shown that in case of buildings with internal braces, as the building’s height increases, the share of higher stories of the hysteresis energy rises. Also, it was illustrated that hysteresis energy distribution in buildings with internal braces is more uniform than those with external ones.

A finite difference scheme for convection term discretization, called BSOU (stands for Bounded Second Order Upwind), is developed and its performance is assessed against exact or benchmark solutions in linear and non‐linear cases. It employs a flux blending technique between first order upwind and second order upwind schemes only in those regions of the flow field where spurious oscillations are likely to occur. The blending factors are calculated with the aid of the convection boundedness criterion. In all cases the scheme performed very well, minimizing the numerical diffusion errors. The scheme is transportive, conservative, bounded, stable and accurate enough so as to be suitable for inclusion into a general purpose solution algorithm.

This paper aims to simulate a punch shear test of partly consolidated ice ridge keel by using a three-dimensional discrete element method. The authors model the contact forces between discrete ice blocks with Hertz–Mindlin contact model. For freeze bonds between the ice blocks, the authors apply classical linear cohesion model with few modifications. Based on punch shear test simulations, the authors are able to determine the main characteristics of an ice ridge from the material parameters of the ice and freeze bonds.

The authors introduced a discrete model for ice that can be used for modelling of ice ridges. The authors started with short introduction to current status with ice ridge modelling. Then they introduced the model, which comprises Hertz–Mindlin contact model and freeze bond model with linear cohesion and softening. Finally, the authors presented the numerical results obtained using EDEM is commercial Discrete Element Modeling software (EDEM) and analysed the results.

The Hertz–Mindlin model with cohesive freeze bonds and linear softening is a reasonable model for ice rubble. It is trivial that the ice blocks within the ice ridge are not spherical particles, but according to results, the representation of ice blocks as spheres gave promising results. The simulation results provide information on how the properties of freeze bond affect the results of punch shear test. Thus, the simulation results can be used to approximate the freeze bonds properties within an ice ridge when experimental data are available.

As the exact properties of ice rubble are unknown, more research is required both in experimental and theoretical fields of ice rubble mechanics.

Based on this numerical study, the authors are able to determine the main characteristics of an ice ridge from material parameters of ice and freeze bonds. Furthermore, the authors conclude that the model creates a promising basis for further development in other applications within ice mechanics.