T. Klekiel

Investigation of Evolutionary Algorithm Effectiveness in Optimal Synthesis of Certain Mechanism

This paper presents the comparison of four evolutionary algorithms (EA) in terms of their effectiveness as applied to solve an engineering optimization task. The four tested algorithms differed in structure. The problem to be solved concerned optimization of a four-bar linkage dimensions so that its movement follows a given trajectory. Best EA parameters values were sought, namely: crossover probability, mutation probability and pool size. The main EA evaluation criterion was the number of iterations necessary to set the size of a mechanism that would realize the trajectory with a given tolerance. Substantial dispersion of results obtained from the algorithms after multiple repetitions of calculations were observed. For that reason the second criterion was introduced, a statistical measure of iterations number dispersion. The combined criteria, the number of iterations and standard deviation, enabled different EAs effectiveness comparison and indicated proper selection of their parameters values.

Analysis of the Lower Limb Model Response Under Impact Load

The paper presents a problem of soldiers’ lower limbs safety in military vehicles during high impact loads derived from explosion of Improvised Explosion Devices (IED) charges. The numerical studies concerned the function of combat boots as an element of the soldier’s equipment. The model of a lower limb with cooperation with a sole was prepared as a multibody dynamic system. For this model the governing equations have been prepared and solved numerically with the Runge-Kutta method. The results were obtained for the load acting on the sole as the velocity generated proportionally in relation to the mass of an IED charge. The changes of material property for the sole were analysed to select the best parameters for protection of both a foot and a whole leg. The results show the conditions for increasing the safety of a passenger’s feet formulated as damping properties for soles and were compared with the similar data from an experimental study.

Prediction of the Segmental Pelvic Ring Fractures Under Impact Loadings During Car Crash

The Pelvis is the most susceptible part of the body to damage during car accidents and is characterized by the highest mortality rate, especially in the case of multiple fractures. The mechanism of these fractures remains unclear and this makes the development of effective crash protection more difficult. A geometric model of the lumbo-pelvic-hip complex (LPHC) including elements of skeletal, muscular and ligament structure stabilizing the pelvis was elaborated on the computed tomography images of a 25-year-old patient. The influence of pelvic boundary conditions on the type of injuries was subjected to analysis using the Finite Element Method (FEM). The cases of a model anchorage dependent on the position of the passenger’s body in the vehicle, where the impact of interior vehicle elements, such as seat belts or a car seat, were taken into account. A fracture threshold was established by applying lateral loads from 0 to 10 kN to a greater trochanter of the femoral bone in each of a five cases of boundary conditions reflecting the influence of different car parts on a passenger’s body. The magnitude of the contact force between the body and the vehicle parts during a side collision against the driver’s door were determined using the elaborated model. Furthermore, a pelvis lateral collision theory model was built and validated with the use of clinical data. The obtained results can provide an estimate for a threshold of the initial failure in the pelvis bone due to an impact compression transmitted through an overlying tissue. Therefore, it was assumed that the properties of the fractured structure are similar to the cancellous bone.

Application of the Fundamental Solution Method to Object Recognition in the Pictures

Abstract Recognition of objects in pictures and movies requires the use of techniques, such as filtering, segmentation and classification. Image filtering is required to remove all artifacts that hinder the unequivocal identification and sharpen interesting objects. Segmentation refers to finding areas of images respected to individual objects. For the selected areas corresponding to objects in the selected picture, the classification of objects finally gives information about the type of object which orientation is made. This paper presents a method for the classification of objects from drawings as a bitmap using the method of fundamental solutions (MFS). The MFS was tested on the selected bitmap depicting simple geometric shapes. The correlations between errors occurring on the boundary for particular shapes are used for the selection of geometric shape figures. Due to this correlation, it is possible to recognize the shape of the image appearing on the drawing by an analysis consisting of the comparison of recognized points describing the shape of contour to a database containing solutions of boundary value problems for the selected shape. In one way, the comparison of the pattern can determine which shape from database it is most similar to in terms of contour. This article appear that this approach is very simple and clearly. In result, this method can be used to recognition of the objects in the systems of real-time processing.