Approaches to the Determination of the Working Area of Parallel Robots and the Analysis of Their Geometric CharacteristicsDmitry MALYSHEV, Mikhail POSYPKIN, Larisa RYBAK & Alexander USOV
The article presents and experimentally confirms two approaches to the problem of determining the working area of parallel robots using the example of a planar robot DexTAR with two degrees of freedom. The proposed approaches are based on the use of constraint equations of coordinates. In the first approach, the original kinematic equations of coordinates in the six-dimensional space (two coordinates describing the position of the output link and four coordinates – the rotation angles...
Development of Non-Contact Fatigue Crack Propagation Monitoring Method Using Air-Coupled Acoustic Emission SystemTakuma MATSUO & Daisuke HATANAKA
A monitoring system for fatigue crack propagation was developed using a non-contact acoustic emission (AE) monitoring system. The AE signals generated during the plane bending fatigue test were first monitored. The AE generation rate increased after approximately 0.5 of the fatigue life ratio. The maximum amplitude of the AE signals increased with a tendency similar to that of the crack propagation. The sensor sensitivities for the flat and arced surfaces were then compared. The sensitivity...
This research aims to study the fastening rotation behavior of cold-formed steel screw connections by experimental testing and analytical modelling. Both the experimental test and finite element results showed the failure modes of tilting and bearing failure. The rotation failure mode of the screw connection was studied by an analytical method using a spring model with screw-plate stiffness which included the bending and shear stiffness of the screw and the bearing stiffness of the screw...
Impact of Thermophoretic Transport of Al2O3 Nanoparticles on Viscoelastic Flow of Oil-Based Nanofluid over a Porous Exponentially Stretching Surface with Activation EnergyChristian John ETWIRE, Ibrahim Yakubu SEINI, Musah RABIU & Oluwole Daniel MAKINDE
The influence of thermophoretic transport of Al2O3 nanoparticles on heat and mass transfer in viscoelastic flow of oil-based nanofluid past porous exponentially stretching surface with activation energy has been examined. Similarity technique was employed to transform the governing partial differential equations into a coupled fourth-order ordinary differential equations which were reduced to a system of first-order ordinary differential equations and then solved numerically using the fourth-order Runge-Kutta algorithm with a shooting method. The results for...
Study of the Distribution of Normal Contact Pressure Between Parts Joined in a Multi-Bolted System under Operational LoadsRafał GRZEJDA
Modelling and calculations of unsymmetrical multi-bolted connections treated as a system for different bolt models and contact layer models between the joined parts are presented. The modelling refers to preloaded and externally loaded connections. The systemic models of the connection for two substitute models of bolts are shown. Between the joined parts two types of the Winkler model of a contact layer are taken into consideration. Calculations were made for an exemplary unsymmetrical connection. Its...
Theoretical and Numerical Analyses of an Aluminium-Concrete Composite Beam with Channel Shear ConnectorsŁukasz POLUS & Maciej SZUMIGAŁA
This paper presents a numerical simulation and a theoretical investigation of an aluminiumconcrete composite (ACC) beam subjected to bending. ACC structures are similar to steel-concrete composite (SCC) structures. However, their girders are made of aluminium instead of steel. The use of ACC structures is limited because of the lack of relevant design rules. Due to this fact the authors suggest applying the theory for SCC structures to ACC structures. In this paper, the methods for...
A new analytical algorithm for determining the elastoplastic parameters for soft, medium and hard plastic cohesive soils, corresponding to *MAT_005_SOIL_AND_FOAM material model available LS-Dyna FE code, was formulated. The numerical modelling of the post-soil subsystem, applicable in the modelling of road safety barrier crash tests using this material model of the roadside dehydrated ground, was developed. The methodology was presented on the example of a Sigma-100 steel post partly driven into the soil and subjected...
Weakened Zones in Wood – Based Composite Beams and Their Strengthening by CFRP: Experimental, Theoretical, and Numerical AnalysisKrzysztof KULA, Tomasz SOCHA & Arkadiusz DENISIEWICZ
This paper looks at the mechanical behaviour of wood-based beams. Laboratory tests of an I-beam show a considerable decrease of capacity in the weakened zones, e.g., at the connection between two pieces of pine wood used as a flange. We propose strengthening of the zones using fibre composite tapes based on CFRP. This article demonstrates the way for protection of the I-beam with defects in the bottom flange against the loss of load-carrying capacity. The...
One of the factors determining comfort in buildings is the indoor air temperature of the rooms. A control system, part of the home automation system, should stabilise air temperature to the desired level, despite various disturbances such as the presence of random or occasional sources of heat. Inaccurate models of the dynamics of air temperature changes in buildings prescribe the use of robust control methods, a type of which is the sliding mode controller. This...
Analytical and Numerical Studies of an Unsymmetrical Sandwich Beam – Bending, Buckling and Free VibrationKrzysztof MAGNUCKI, Ewa MAGNUCKA-BLANDZI, Jerzy LEWIŃSKI & Szymon MILECKI
The subject of the paper is an unsymmetrical sandwich beam. The thicknesses and mechanical properties of the beam faces are different. Mathematical model of the beam is formulated based on the classical broken-line hypothesis. The equations of motions of the beam is derived on the ground of the Hamilton’s principle. Bending, buckling and free-vibration are studied in detail for exemplary unsymmetrical structure of the beam. The values of deflection, critical force and natural frequency are...
The Impact of Temperature Oscillations and Heat Transfer Conditions in Thick-Walled Elbows and Tubes on the Local Stress-Strain Behaviour During the Fast Start-Up of Power BoilersJerzy OKRAJNI & Krzysztof WACŁAWIAK
The paper presents results of tests designed for predicting the behaviour of components subjected to variable temperature and mechanical loading conditions. Elbows and tubes, as examples of components widely used in power plant pipelines, have been examined. This analysis includes a description of model characteristics, the operating parameters of devices under industrial conditions, and the results of computational modelling (FEM).
Poznań University of Technology4
Phetchabun Rajabhat University2
AGH University of Science and Technology2
Cracow University of Technology1
Dorodnitsyn Computing Centre1
China University of Mining and Technology1
Lublin University of Technology1
Przemysłowy Instytut Motoryzacji1
Jan Grodek State Vocational Academy in Sanok1
Silesian University of Technology1
Belgorod State Technological University1
Institute of Fundamental Technological Research1
Rajamangala University of Technology1