There is a big variety of machines and equipment – internal combustion engines, aviation
parts, building frames - joined by threaded joints, realized as bolt, nut and pin ones. For successful
and safe exploitation of such equipment, it is required to check the tightening degree of threaded
joints. There are few known methods of such control and one is presented in this paper. The
proposed method is based on contact stiffness and friction change from thread tightening degree. At
the same time, tightening changes with sufficient significance the dynamical properties of such a
system - natural and resonance frequencies, amplitude – frequency and amplitude-phase
characteristics, so, that it is possible to evaluate the tightening degree of the investigated joint.
Dynamic properties are defined by exciting transient process between bolt head and tightened by
this bolt detail using as short as possible force impact. Sensors register analogical signal of transient
process and transmit it to a special computer card. The computer card converts analogical signal to
code. Code is saved in the computer file for further processing. Processing data is saved in this file,
and we find desired dynamical characteristics. Using special experimental bench proved that
dynamic characteristics are sensitive enough to threaded joint tightening degree and the method is
applicable to practice.
For synchronization of sections of modern printing machines and equipment of such sections, driven by individual drives the system of “electronic shaft” is widely used. A development of the mathematical model of such a local drive, consisting of mechanical and electric-electronic parts as well as links between them, is provided. The model with an effective adaptive control block for increasing accuracy of the drive is provided in the form of a structural scheme. It, first of all, is usable for investigations of linear and nonlinear dynamic processes that take place in the mechanical part of the drive. Processes that take place in the electric drive are not detailed in this article. An example of the application of the model is provided.
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