Stochastic analysis of lattice, nonlocal continuous beams in vibration

In this paper, we study the stochastic behavior of some lattice beams, called Hencky bar-chain model and their non-local continuous beam approximations. Hencky bar-chain model is a beam lattice composed of rigid segments, connected by some homogeneous rotational elastic links. In the present stochastic analysis, the stiffness of these elastic links is treated as a continuous random variable, with given probability density function. The fundamental eigenfrequency of the linear difference eigenvalue problem is also a random variable in this context. The reliability is defined as the probability that this fundamental frequency is less than an excitation frequency. This reliability function is exactly calculated for the lattice beam in conjunction with various boundary conditions. An exponential distribution is considered for the random stiffness of the elastic links. The stochastic lattice model is then compared to a stochastic nonlocal beam model, based on the continualization of the difference equation of the lattice model. The efficiency of the nonlocal beam model to approximate the lattice beam model is shown in presence of rotational elastic link randomness. We also compare such stochastic function with the one of a continuous local Euler-Bernoulli beam, with a special emphasis on scale effect in presence of randomness. Scale effect is captured both in deterministic and non-deterministic frameworks.

DYNAMICS OF ANTHROPOMORPHIC MANIPULATOR WITH ELASTIC LINKS IN USE OPTIMUM MOTION CONTROL

The optimal rotational motion of the anthropomorphic manipulator with elements of finite rigidity is investigated from the initial to the final state of absolute quiescence using skew–symmetric controls of the "acceleration–deceleration" type. The motion of the links is divided into figurative (providing the purpose of the movement) and relative (elastic oscillations of the links). Absolute quiescence at the end of motion is achieved as a sum of figurative and relative quiescence.

Research of electric car dynamics

Recently, electric vehicles are becoming widespread throughout the world, so the research is relevant. The results of performedresearches of dynamics electric car on the basis of ZAZ-1102 are presented. The calculation method of dynamic loadsin electric and mechanical systems of electric cars is developed. The technique considers the electromagnetic processes in theengine, the elasticity of the elastic parts, the oscillatory processes, and damping in the elastic links. On the basis of the developedmathematical model and using the mathematical software apparatus MathCAD, calculations of transients in the electricand mechanical systems have been obtained, based on the obtained results of the research, the constructed graphs.The obtained results of the study of the electric motor drive mechanism can be used for designing, calculating and determiningthe dynamic loads of electric cars and their hybrids.