Partner: Lech Knap

Warsaw University of Technology (PL)

Recent publications
1.Faraj R., Holnicki-Szulc J., Knap L., Seńko J., Adaptive inertial shock-absorber, SMART MATERIALS AND STRUCTURES, ISSN: 0964-1726, DOI: 10.1088/0964-1726/25/3/035031, Vol.25, pp.035031-1-9, 2016
Abstract:

This paper introduces and discusses a new concept of impact absorption by means of impact energy management and storage in dedicated rotating inertial discs. The effectiveness of the concept is demonstrated in a selected case-study involving spinning management, a recently developed novel impact-absorber. A specific control technique performed on this device is demonstrated to be the main source of significant improvement in the overall efficiency of impact damping process. The influence of various parameters on the performance of the shock-absorber is investigated. Design and manufacturing challenges and directions of further research are formulated.

Keywords:

adaptive impact absorption, adaptive inerter, semi-active control, shock-absorber

Affiliations:
Faraj R.-IPPT PAN
Holnicki-Szulc J.-IPPT PAN
Knap L.-Warsaw University of Technology (PL)
Seńko J.-Warsaw University of Technology (PL)
2.Suwała G., Knap L., Holnicki-Szulc J., Prestressing for Reduction of Local Vibrations in a Rotorcraft, ENGINEERING TRANSACTIONS (ROZPRAWY INŻYNIERSKIE), ISSN: 0867-888X, Vol.64, No.3, pp.367-380, 2016
Abstract:

The main objective of this paper is to investigate the possibility of local structural vibration uppression via introducing initial prestressing. In order to evaluate the effectiveness of the proposed method, a two-step approach has been used. Firstly, a prestressed modal analysis has been conducted to measure the influence of the prestressing on changes of eigenfrequencies and eigenmodes. In the second step, a steady dynamic analysis has been performed to harmonic excitation to demonstrate the reduction of local amplitudes. Numerical experiments have been conducted on the model of a small rotorcraft. Our results indicate that introduction of initial prestressing may be used to affect natural structure frequancies and to lower amplitude of vibrations of the structure exposed to external extortions.

Keywords:

Prestressing, vibration suppression.

Affiliations:
Suwała G.-IPPT PAN
Knap L.-Warsaw University of Technology (PL)
Holnicki-Szulc J.-IPPT PAN

Conference papers
1.Suwała G., Knap L., Holnicki-Szulc J., Prestressing for local isolation of forced vibrations, EACS2016, 6th European Conference on Structural Control, 2016-07-11/07-13, Sheffield (GB), pp.1-8, 2016
Abstract:

The problem of dynamic response stabilization is a crucial issue in many engineering applications or structures subjected to an external source of excitation or dynamic load. At present, owing predominantly to advances in measurement technology, microprocessor control and development of smart materials it is possible to solve many of these problems. Semi-active or active damping systems, which are used to improving structure response, requires additional dampers or absorbers. Contrary, in the article we present approach of suppressing local vibration via introducing initial prestressing into the chosen element or elements of the structure. In that way it is possible to change properties of the structure and its modes of vibrations. We present the results of numerical simulations of the mechanical structure subjected to external excitations. Our results show that by introducing prestressing it is possible to significantly influence on eigenfrequances and eigenmodes. Also effectiveness of vibration amplitudes reduction can be significantly larger, at least one order of magnitude larger.

Keywords:

local suppresion of forced vibrations, prestressing, sensitivity analysis and prestress optimization

Affiliations:
Suwała G.-IPPT PAN
Knap L.-Warsaw University of Technology (PL)
Holnicki-Szulc J.-IPPT PAN

Conference abstracts
1.Faraj R., Graczykowski C., Holnicki-Szulc J., Knap L., Seńko J., Adaptable pneumatic shock-absorber, SMART 2017, 8th Conference on Smart Structures and Materials, 2017-06-05/06-08, Madrid (ES), pp.1, 2017
2.Faraj R., Holnicki-Szulc J., Knap L., Seńko J., Mitigation of the structure response based on inertial shock-absorber, EACS2016, 6th European Conference on Structural Control, 2016-07-11/07-13, Sheffield (GB), pp.1, 2016
Abstract:

The goal of this paper is to present further development of the inertial shock-absorber called SPINMAN. Application of the device in mitigation of structures response is investigated and selected case study is discussed. The specific construction and operation of the device is introduced and explained. In reference to the impact absorption problems, the SPIN-MAN is a concept of adaptive inerter device with two phases of operation. The first of them includes energy absorption and accumulation. External energy of the load is converted to kinetic energy of rotational motion of the mass. During the second phase, accumulated energy is dissipated by inverse spinning of the second mass powered by the remaining part of the impact energy. To obtain this type of operation, special switchable actuators are used. Applicability of the device in mitigation of impact-born structure response, especially in case of space systems, is investigated. General concept of the device construction and operation is adjusted to meet the requirements for space systems. This results in a fluidless, passive-like solution but adaptable to the load conditions. Tuning of the shock-absorber may be realized by manual or easily automated mechanical adjustments. Effectiveness of the solution is based on the specific on/off type of control, which is responsible for the optimal energy flow in the system and efficient dissipation of impact energy inside the SPIN-MAN. Results of numerical simulations confirmed quick and effective operation of this device.

Keywords:

structure response mitigation, adaptive impact absorption, adaptive inerter, semi-active control, shock-absorber

Affiliations:
Faraj R.-IPPT PAN
Holnicki-Szulc J.-IPPT PAN
Knap L.-Warsaw University of Technology (PL)
Seńko J.-Warsaw University of Technology (PL)

Patents
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pdf
415131
2015-12-04
BUP 12/2017
2017-06-05
Holnicki-Szulc J., Knap L., Faraj R., Seńko J.
Amortyzator śrubowy z krótkimi łopatkami i amortyzator śrubowy z długimi łopatkami
PL, Instytut Podstawowych Problemów Techniki PAN, Adaptronica Sp. z o.o.
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414970
2015-11-26
BUP 12/2017
2017-06-05
Holnicki-Szulc J., Knap L., Faraj R., Seńko J.
Amortyzator śrubowo-rotacyjny z jednym wejściem i amortyzator śrubowo-rotacyjny z dwoma wejściami
PL, Instytut Podstawowych Problemów Techniki PAN, Adaptronica Sp. z o.o.
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414367
2015-10-14
BUP 9/2017
2017-04-24
Holnicki-Szulc J., Knap L., Seńko J., Faraj R.
Urządzenie do tłumienia udaru i sposób tłumienia udaru
PL, Instytut Podstawowych Problemów techniki PAN, Adaptronica Sp z o.o.
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