Investigation of vibrations caused by the inaccuracy of transmission of the mechatronic system

The questions connected with dynamics of mechatronic system at certain radial misalignment of shafts are investigated in offered work. As object of research is the system of two shafts connected by elastic centrifugal ring coupling. It is established, that in coupling, connecting radially misaligned shafts, an internal moment of resistance to rotation is arising. Using principle of d’Alamber for rotary movement, and it is worked out the differential equation describing rotation of the second shaft, and received solutions show, that rotational fluctuations arise in rotating misaligned system. The frequency of fluctuations is double rotation frequency. The results of investigation were applied for vibration reducing of mechatronic system

Vibration dampers for transmission of mechatronic systems

The paper reviews original torsional vibration dampers retaining their efficiency in a wide disturbing frequency band. Some potential design alternatives are considered. The basic structural element of the damper is a rotary flexible ring. The mathematical model of the system estimates inertia, flexible and gyroscopic terms. The equations to calculate the system motion are derived and stability conditions for the system dynamic balance are formulated, proper consideration is given to other possible stability loss forms and regions of the flexible ring. The analysis of the system natural frequencies is made. Efficiency estimation of the damper versus various parameters is effected following the expression of the equivalent inertia moment and its limit value

Research of Cargo Delivery Errors by Conveyance using Lifting Mechanism

The mechanical properties of the rope - stiffness and internal friction changes during the movement of cargo. For this reason, under the influence of gravity and inertial forces in the rope having varying tension. Thus, the lift mechanism further exposed to dynamic loads. The highest value of this load is obtained at the beginning of lifting and lowering in place. The mathematical model of the lift mechanism was investigated using the original software package and found dynamic load. In modern control system used cranes lifting mechanism, taking into account the deviation from the vertical rope. Dynamic load on the rope can distort the signals. Results are used to improve the control system of the lifting mechanism

Investigation of rotary system containing a flexible centrifugal coupling with controlled damping

The possibility of isolation of the driving shaft of the vehicle from vibrations of the engine shaft using a coupling with a controlled damping element based on magnetorheological liquid and a supplemental disc connected to the driving or driven half–coupling is discussed herein. The impact of the parameters of the coupling and the feedback upon the amplitude– frequency response of the system is analyzed. It is demonstrated that effective damping of vibrations in the resonance zone is possibl

Research of Elastic Parameters of Paper and Prints

Knowledge of the elastic properties of prints during printing processes is essential in printing presses. A computational inverse technique is presented to determine the elastic properties of materials. An effective technique for identification of elastic properties of prints consisting of the paper and several layers of ink and varnish is based on experimental data of modal vibration testing and finite element modelling. The aim of finite element modelling and optimization is to guess the material properties obtaining the same vibration frequencies and modes while test specimen is loaded in the same way as on printing press. Proposed technique can be used for the printing process modelling as non-destructive method during the initial design stage

Research of dynamics of lifting equipment

In the recent years, girder bridge cranes are replaced by double-beam overhead cranes with beams of rectangular cross-section. In addition, new materials are used for their fabrication, characterized by different values of allowable loads and deformations. In the paper, two overhead cranes from JSC "Vilniaus kranai" are considered. A mathematical model is proposed that enables assessment of the impact of the hydraulic damper built in the cargo suspension system upon the dynamic features of the crane in the beginning of the lifting process. It was determined that in such a way the period of vibration damping is reduced. However, the impact of the damper upon the dynamics of the metal structure of the crane is limited because of high mobility of the rope as compared to the mobility of the total structure

Vibration dampers for transmission of mechatronic systems

The paper reviews original torsional vibration dampers retaining their efficiency in a wide disturbing frequency band. Some potential design alternatives are considered. The basic structural element of the damper is a rotary flexible ring. The mathematical model of the system estimates inertia, flexible and gyroscopic terms. The equations to calculate the system motion are derived and stability conditions for the system dynamic balance are formulated, proper consideration is given to other possible stability loss forms and regions of the flexible ring. The analysis of the system natural frequencies is made. Efficiency estimation of the damper versus various parameters is effected following the expression of the equivalent inertia moment and its limit value

Investigating possibilities of a table vibrator with controlled damping

This paper considers the possibility of ensuring a desired regime of vibrations of the table vibrator with a support, where a damping element with a magnetorheological fluid is used. A feedback system is employed for control of the damping element. The system receives signals from the accelerometer that measures the vibrations of the table vibrator. Solution of the equations describing vibrations of the table vibrator demonstrated that double integration of signals of the accelerometer ensures a stable regime of vibrations for varying mass of a product. If the signal of the accelerometer is integrated once and then passes through a frequency detector, a dangerous increase of the vibrations in the resonance zone is avoide

Investigating possibilities of a table vibrator with controlled damping

This paper considers the possibility of ensuring a desired regime of vibrations of the table vibrator with a support, where a damping element with a magnetorheological fluid is used. A feedback system is employed for control of the damping element. The system receives signals from the accelerometer that measures the vibrations of the table vibrator. Solution of the equations describing vibrations of the table vibrator demonstrated that double integration of signals of the accelerometer ensures a stable regime of vibrations for varying mass of a product. If the signal of the accelerometer is integrated once and then passes through a frequency detector, a dangerous increase of the vibrations in the resonance zone is avoide

Ovarian Strumal Carcinoid: Case Report, Systematic Literature Review and Pooled Analysis

Background: Ovarian strumal carcinoid is a rare tumor in which thyroid (struma) and carcinoid components coexist. The disease is generally considered to be a borderline malignancy, however, cases with metastatic disease have been described. No data in the literature are available to guide diagnosis and therapy. Methods: We performed a pooled analysis and a systematic review of histopathological-confirmed strumal carcinoid cases published in the literature using the following keywords: “strumal carcinoid of the ovary”, “strumal carcinoid case report”. A case of strumal carcinoid tumor diagnosed and followed-up at the Medical Oncology Unit of Spedali Civili (Brescia, Italy) was also described and included. Results: Sixty-six eligible publications were identified, providing data from one hundred and seventeen patients, plus a case diagnosed at our institution. At presentation, among the eighty-eight patients with symptomatic disease, 37% of patients suffered from abdominal distention and 49% from pain due to a growing abdominal tumor mass, 37% from constipation (peptide YY was analyzed in only nine of them, resulting above the physiologic range). Surgery was the primary therapy in 99% of the patients. Three patients had metastatic disease at diagnosis and five patients underwent recurrence after radical surgery. Histology at disease recurrence concerned the thyroid component in two patients, the carcinoid component in two patients, both histologies in one patient. Median disease-free survival and overall survival in this series were not attained. Conclusion: Strumal carcinoid of the ovary generally presents a benign behavior and surgery is curative in most cases. However, a small group of patients with this disease can undergo disease recurrence due to both the thyroid and the neuroendocrine (carcinoid) components. A follow-up in radically operated patients is therefore needed, particularly in those with a voluminous disease at diagnosis