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Semi-active linear vacuum packed particles damper

100%

Zalewski R. , Chodkiewicz P.

tom Vol. 54 nr 1

311--316

In this paper, the authors focus on the proposition of an innovative semi-active linear damper prototype working on the basis of granular materials. Vacuum Packed Particles (VPP) belong to the class of materials whose mechanical (rheological, dissipative) properties may be quickly changed by applying a partial vacuum inside the system. The concept of an innovative linear damper based on VPP is presented in the paper. Typical experimental results are presented to reveal changeable damping characteristics of the device. Additionally, the mathematical model is proposed to capture extraordinary features of the investigated damper.

Preliminary study of the Vacuum Packed Particles torsional damper

100%

Zalewski R. , Rodak D.

2021

tom Vol. 59 nr 1

173--178

The paper presents a prototype of an innovatory controllable torsional damper. The device is composed of Vacuum Packed Particles. Such structures are made of granular materials placed in a hermetic soft encapsulation. Generating so called underpressure inside the system changes global dissipative properties of the granular structure. The partial vacuum value is a convenient way to control physical properties of the granular structure. The authors introduce an original prototype of a torsional vibration attenuator. In the experimental part, preliminary experimental results are presented and discussed. To capture the real response of the device, a Bouc-Wen rheological model is adopted.

The use of Vacuum Packed Particles with adaptable properties in acoustic applications

100%

Zalewski R. , Rutkowski M.

Journal of Theoretical and Applied Mechanics

2018

tom Vol. 56 nr 2

403--416

The aim of this paper is to present possibilities of using a new type of granular media in acoustics as innovative sound absorbers. Most materials of this type have a porous or fibrous structure. It is constant, and once manufactured, does not easily change its configuration. The examined material – Vacuum Packed Particles (VPP) is of a changeable structure. It can be assumed that the acoustical absorption of such structures can be modified and partially adjusted by an external factor. First steps in an experimental approach have been made – the acquired results are optimistic. Additional tests are being planned to confirm the observed phenomenon and to apply VPP as novel materials in acoustics. Basing on the preliminary experimental tests, it can be concluded that the considered structures could become a significant part of a multilayered structure which would have controllable sound absorption properties.

Possibilities of vacuum packed particles application in blast mitigation seats in military armored vehicles

63%

Rodak D. , Żurawski M. , Gmitrzuk M. , Starczewski L.

Bulletin of the Polish Academy of Sciences. Technical Sciences

2022

tom Vol. 70, nr 1

art. no. e138238

Blast mitigation continues to be a popular field of research when military vehicles are concerned. The main problem is coping with the vehicle global motion consequences following an explosion. The paper presents a potential application of the linear vacuum packed particle (VPP) damper as a supplementation for a viscous shock absorber in a traditional blast mitigation seat design. The paper also presents field test results for the underbelly blast explosion, comparing them to the laboratory tests carried out on the impact bench. To collect accelerations, the anthropomorphic test device, i.e. the Hybrid III dummy, was used. A set of numerical simulations of the modified blast mitigation seat with the additional VPP linear damper were revealed. The VPP damper was modeled according to the Johnson–Cook model of viscoplasticity. The Hertzian contact theory was adopted to model the contact between the vehicle and the ground. The reduction of the dynamic response index (DRI) in the case of the VPP damper application was also proved.

Parameter identification of Bouc-Wen model for vacuum packed particles based on genetic algorithm

63%

Bartkowski P. , Zalewski R. , Chodkiewicz P.

2019

tom Vol. 19, no. 2

322--333

This paper investigates cylindrical samples made of vacuum packed particles. Such structures are composed of granular media placed in a hermetic encapsulation where, in the final stage, a partial vacuum is generated. The main advantage of such a structure is that the underpressure value makes it possible to control the global physical properties of granular systems. Materials with various grains are analyzed in the paper. A modified Bouc-Wen hysteresis model is adopted to describe the nonlinear properties of the tested specimens. To identify the model parameters, a genetic algorithm is applied. The proposed model is found to be in good agreement with the experimental data.

Preliminary research of a symmetrical controllable granular damper prototype

51%

Mackojc A. , Chilinski B. , Zalewski R.

Bulletin of the Polish Academy of Sciences. Technical Sciences

2022

tom Vol. 70, nr 3

art. no. e141002

This paper concerns the problem of empirical investigation and mathematical modelling of a novel controllable damper using Vacuum Packed Particles. Vacuum Packed Particles tend to be placed among the group of so-called ‘smart structures’. The macroscopic mechanical features of such structures can be controlled by the partial vacuum parameter. The authors consider an application of Bouc-Wen model in order to represent the dynamic behaviour of the investigated device. The verification of the model response with experimental data is discussed. The Bouc-Wen model parameters identification is described.