This contribution gives an overview about new procedures for the parameter identification for the material characterisation of rubber blends. They are based on a Newton-Raphson procedure and a genetic algorithm. As basis serves an experimental investigation of the viscous properties of rubber blends by means of a capillaryviscometer. Because of simultaneous consideration of wall slippage, temperature and of the die swell, the proposed material characterisation is represented by a coupled system of nonlinear equations. Describing their solutions requires a numerical integration algorithm. For this purpose a generalized Newton-Raphson scheme has been adopted. The verification of the developed parameter identification was done by means of another approach which is based on a genetic algorithm.

In this contribution, an overview over a numerical scheme for the crack modelling of spruce wood under tensile loading is given. A material model for biaxially stressed spruce wood with consideration of the effect of knots on the strength properties has been developed. A necessary feature of this material model is its ability to treat cracks by means of the so-called smeared crack concept. For this reason the consideration of a so-called characteristic length in the corresponding evolution laws of the strength values is required. The successful implementation in the material model is shown by means of various numerical examples.

The paper contains a comparison of the results of calculation and experiment for the IOHNAP alloy steel. Specimens made of this steel were subjected to uniaxial constant-amplitude and random loading with both zero and non-zero mean values of loading. For determination of the steel fatigue life, the energy parameter including the mean value of loading was proposed. Under random loading, cycles were counted with the rain flow algorithm, and fatigue damage was accumulated with the Palmgren-Miner hypothesis. For the registered stress histories, elastic-plastic strains were calculated with the kinematic hardening model proposed by Mróz.

In the paper, the author presents a certain method of calculation of Horizontal Axis Wind Turbine (HAWT) performance for yawed flow conditions. The presented model is developed on the basis of propeller theory described in [23). Te model employs the results of the vortex theory of propeller combined with momentum and angular momentum theorems for the HAWT wake. In the model, the blade element is regarded as a source of tangential and axial force acting on air at actuator disk surface. The momentum equations are corrected for the effect of finite number of blades by introduction of Prandtl tip-loss factor to the equations. Thanks to the approximation of lift force coefficient vs. angle of attack by sine curve, one may get a quadratic equation for local axial velocity component. Tangential component of induced velocity may be calculated from relations obtained from vortex theory of HAWT. This allows us to avoid an iterative solution for induced velocity, unlike in most of the HAWT and propeller theories. The blade section drag is incorporated to calculations of total drag of rotor and power, when induced velocity components are known, and hence blade element angle of attack is determined. To incorporate the effect of blade element stall-delay due to blade rotation, a simple semi-empirical model proposed by Tangier and Selig has been applied. The calculations are compared with experimental data obtained at Riso 100 kW experimental turbine test site and at the Grumman Wind Stream 33 turbine modified by NREL. The comparison includes power output as well as blade element angles of attack. The presented results show that the method described in the paper underestimates performance for low speed winds, whereas for strong winds the power output is slightly overestimated. For average angles of attack, one may see that for small tip speed ratios angles of attack are overestimated. At high tip speed ratios, however, angles of attack are underestimated. It was shown that there is a need to take into account the work done by side force on the tangential inflow component to obtain correct power curves for yawed flow conditions.

The paper shows the hybrid method of stress and strain distributions analysis. In the method, the results of displacement measurement were used as boundary conditions in the numerical analysis of the tested objects. The numerical analysis was performed with the use of the finite element method (FEM), whereas measurements of displacement were made by laser grating interferometry technique (moire interferometry). Examples of tests presented in the paper show good efficiency of the method in the analysis of stress and strain distribution in the areas of their heterogeneous distribution. Mutual completion of laser grating interferometry and finite element method makes it possible to exclude their disadvantages creating broader' possibilities for research impossible to achieve in separate use.

The paper presents kinetic fatigue crack growth curve for IOHNAP steel, which is verified experimentally. An energy approach based on the M-integral range is shown. The tests have been carried out on plane specimens With notches under tension-compression for three values of stress ratio R. The J-integral is calculated analytically and by the finite element method. A relationship for the description of the whole kinetic crack growth curve including J-integral is presented. It is shown that at the constant loading and the change of stress ratio R from - 1 to O the fatigue crack growth rate increases. A relationship is proposed in the paper for description of the kinetic crack growth curve. It gives results that are consistent with experimental ones and those obtained with the use of the finite element method (FEM).

The article presents a dynamic analysis of the sorting process of load units transported on conveyor belts. The process is realized by means of an active fence with one freedom degree. During analytic research the manipulated loads were treated as undeformable bodies, or in the case of load impact against the fence as the bodies with nonlinear springy-damping properties. A flexible element, described by Kelvin linear model, was used in the drive of the fence of a rotatably fixed beam. Appropriate choice of construction parameters makes it possible to mitigate the dynamic interactions of the sorted loads.

The critical phases of starting of over-resonance vibratory machines were analysed and the strategy of overcoming those phases by low-power engines was proposed in the paper. The variational method based on the Pontriagin's maximum principle as well as method of phase angle modulation was applied. Effectiveness of the proposed solutions was investigated by the numerical simulation.

The effect of processes of accumulating mass and enthalpy of the working medium on the dynamics of transient processes thereof is often discussed in scientific publications on the mathematical modelling of turbine engines (treated as systems that undergo control and automatic adjustment). The paper is intended to make a comparison between findings gained from simulation carried out with two alternative models of an aircraft turbine engine (of the S0-3 type). The first model takes account of the dynamics of the processes of accumulating mass and energy of the working medium within the combustion-chamber volume and that of the convergent nozzle. The second, simplified model, neglects the dynamics of the processes of accumulating mass and energy of the working medium, since it has been assumed that it is the dynamics of the kinetic-energy accumulation in the rotor mass that predominates in various representations of transient processes. To conduct simulation-based experiments, each of the alternative models of an engine was connected to a special simulation unit, which simulated operation of fuel supply and control systems. Two rounds of experiments were carried out. The first one was intended to facilitate observations of transient processes effected with quick shifting of a control lever from the idle position to that of full thrust, and back. In the second round observed were processes resulting from changes in the critical jet area. The second, alternative model was used to investigate the effect of ever-greater hypothetical volumes of the nozzle on how the transient processes proceeded. It has been found that in the case of the S0-3 engine, low nozzle capacity remains of only slight effect on how the transient processes proceed. Hence, simplified modelling methodology is fully justified.

The volume of combustion chamber consists of head and cylinder spaces. The distribution of volumes in the cylinder depends on accuracy of dimensions, determined by the production process, and precision of the crankshaft system assembling. Therefore, the aim of this work is to present a correct method of assembling, and give an example of analysis of crankshaft system dimensions based on the engine family type Wola-135TC.