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This study is devoted to analyzing the thermal buckling behavior and natural vibration characteristics of a uniformly heated rectangular thin plate with two adjacent in-plane frictional sliding edges. These sliding edges are initially at a stick status under the friction forces, and may slightly slip due to the thermal expansion of the plate until the sliding edges contact the stops, i.e. the bounds of the clearances. In the study, both temperature dependencies of material properties and friction coefficients are taken into consideration. For each case, the explicit equations for the buckling temperature rise and the natural frequencies of the plate are derived. Then, some parametric studies are made to reveal the influences of both normal forces and clearances on the critical buckling temperature rise and the natural vibration characteristics of the plate. The results show that both normal forces and clearances have significant influences on the critical buckling temperature rise and the natural frequencies of the plate, especially for the square plate, which has repeated natural frequencies. These results enable one to adjust the normal forces and the clearances in design in order to improve the mechanical performance of a heated rectangular thin plate. [ABSTRACT FROM AUTHOR]

This paper is devoted to the dynamic analysis of two connected beam columns with a variation of the bending connection and minor perturbations of the length of each span. The point of reduced bending stiffness represented by a rotational spring may result from a crack. This rotational spring can also be associated with a semi-rigid connection in the field of steel or composite structures, for instance. The dynamics of this axially loaded two-span weakened column appears to exhibit strong localization for small values of stiffness of the rotational spring. The vibration mode shapes indicate a strong confinement of the vibration level to a fraction of the column. A quantitative criterion of localization is established and is correlated to well-known phenomena such as curve veering effect or close eigenvalues. Such a result is quite encouraging as localization is strongly associated with the flexibility values of the rotational spring. When considering the open crack analogy, localization only appears for severely damaged columns. It can then be understood as an indicator of the damage level of the global structure. [ABSTRACT FROM AUTHOR]

Friction-induced self-sustained oscillations result in a very robust limit cycle that characterizes stick-slip motion. This type of motion should be avoided under any circumstances because it creates noise, wear, and damage. In this paper we show, by simple models, how stick-slip motion can be avoided. Effective methods are: (i) appropriate increase of internal damping that compensates the negative damping induced by a friction characteristic, which decreases with increasing sliding speed; (ii) external excitation that breaks up the limit cycle (however, this often leads to chaotic motion); (iii) passive vibration control by fluctuating normal forces. The last mentioned mechanism is new and will be investigated in detail. The stick-slip oscillator is extended by an additional degree of freedom, which couples the slipping motion to the normal force. The dynamic behavior of the system has been worked out by analytical investigations and numerical integration. Scanning a broad range of values, parameters of the additional system, called the dynamic vibration absorber, have been found that prevent stick-slip and minimize the amplitude of the residual limit cycle. For this task the evaluation of the system behavior has been achieved by observing its energy content. The feasibility of the proposed dynamic vibration absorber is demonstrated by an experiment. [ABSTRACT FROM AUTHOR]