Jacek Stadnicki

Optimal Design of the Cylindrical Shell of a Card Machine

Deflections of a thin cylindrical shell that is used in carding machines, either as a swift or a doffer, are analyzed in this paper. The shell may have supple supports at its edges and inner strengthening in the form of rings. The task of calculating the deflections has been solved by dividing the shell into longitudinal beam elements. The optimization procedure for criteria of mass minimum or deflection minimum is used. A numerical example to define selected construction data is presented along with the results.

Mesoscale finite element model for calculating deformations of laminate composite constructions

This article shows the methodology of building finite element models of composite constructions made of laminate composites reinforced with carbon fibre fabric (carbon-fiber-reinforced polymer). The models use a repeatable microstructure of a composite – a repeated unit cell – which is a three-dimensional truss built with one-dimensional beam finite elements. Thanks to this fact, the models reflect the internal structure of the composite. The model constants have been experimentally determined. Therefore, the influence of production technology of the composite on its mechanical properties has been considered. The modelling methodology has been used to calculate deflections of exemplary composite constructions. The results have been experimentally verified.

Optimisation of Selected Components of a Roller Carding Machine in the Aspect of Improving their Cooperation Quality

The quality of web produced by a carding machine is largely influenced by the shape and height of the gaps between card clothings of workers and the doffer cooperating with the main cylinder as well as between the doffer clothing and doffing blade. The following paper describes the methodology of selection of a structural form and basic dimensions of the carding machine shafts and cylinders taking into account the gap shape in the zones of card clothing cooperation. For the study to be complete, optimisation of the blade and comb shaft cross-sections was also performed. The benefit from optimisation of the card ing machine components is the improvement in the quality of the web – the final product of carding.

Optimization of the structural form of the carding machine main cylinder

The following paper presents the solution to the problem of searching the best shape – structural form of the bottoms and optimal dimensions of the main cylinder of the carding machine with consideration to the criterion of minimal deflection amplitude of its shell. The Finite Element Method has been applied for searching the optimal solution. As a result of the performed analyses, reduction of deflection amplitude at approximately 77% has been obtained. The determined optimal structural form and dimensions of the cylinder enable application of a new textile technology – microfibre carding as well as improvement in the quality of traditional carding technology of woolen and wool-like fibres performed on roller carding machine. The final stage of the work has been to determine the influence of manufacturing tolerances of the cylinder and metallic card wire on the amplitude of the main cylinder deflection.

Nonlinear FEM models optimization on example of a stamping die

Modern software for computer-aided design, using the finite element method, more and more often contain modules for solving optimization tasks. The user may formulate and solve such problems as:  parametric optimization (geometry optimization), where the decision variables are the dimensions or cross-sectional parameters of the FEM model, and the objective function may be stress, nodal displacement or natural frequency;  topological optimization, where the shape of the designed part is sought, which ensures its best distribution in the space due to the criterion of maximum stiffness, minimal natural frequency, etc.;  sensitivity analysis, in which the impact of changing selected parameters of the FEM model on the indicated size (criterion) is examined to determine the relevant parameters and eliminate the non-essential ones due to the improvement of a given criterion. In the mentioned problems, the optimization task is solved:

Simulation of Delamination in a Composite Using a Shell-beam Mesoscale Finite Element Model

The article presents a new method of delamination modelling in a fabric-reinforced laminate using a shell-beam mesoscale FE model. This original laminate model enables the analysis of the resistance of composite structures in which the reinforcement can be technical fabric of various weaves or a layer of parallel rovings, e.g. made of carbon fibers. It includes an experimental part in which flat specimens of laminate were delaminated according to three basic schemes: tensile opening, sliding shear and tearing shear. The aim of the experimental studies was to obtain load-displacement curves, which were used to define the conditions of initiation and propagation conditions of cracks in the calculation model as well as to perform their experimental verification. Specimens of the laminate tested were modelled using a mesoscale FE model, in which the components, i.e. the rovings, were modelled in a simplified manner with finite elements of the beam type and a matrix with finite elements of the shell type. The bondings between adjacent laminate layers were also modelled with beam elements. The simulation results were compared with those of experimental delamination tests, and the convergence obtained confirmed the correctness of the modelling method developed.

Stamping Die Modelling with Consideration to Drawpiece Springback Phenomenon

Drawpieces made of advanced high-strength steel (AHSS) usable for production of self-supporting car bodies are characterized by the presence of the springback phenomenon caused by the stress relaxation of the elastic part which is the result of stamping. Its compensation requires proper verification of die tools. The presented paper describes a methodology using CAE for die design. The methodology solves an optimization problem determining the verified shape of die tools upon taking into account the consistence of the drawpiece shape with the shape postulated in the project. The real drawpiece was used to judge the usefulness of the methodology in die design.

Evaluation of the feeder duct strength during short circuit

Streszczenie: Szynoprzewody, służące do przewodzenia dużych prądów, powinny zapewniać bezpieczną eksploatacją również podczas przewodzenia udarowego prądu zwarcia – kiedy działa na nie siła pola elektromagnetycznego o dużej wartości. W artykule przedstawiono dyskretny model MES do analizy naprężeń i deformacji segmentu szynoprzewodu w stanie zwarcia. Ponieważ analizowana konstrukcja okazała się bezpieczna, wyznaczono największy rozstaw podpór szynoprzewodu, przy którym jego eksploatacja jest jeszcze bezpieczna. Powiększenie rozstawu podpór szynoprzewodu pozwala na zwiększenie długości segmentu i obniżenie jego kosztów.

Numerical Effectiveness of the Simulation of an Automotive Body Part Stamping

The simulation of advanced high-strength steel sheet (AHSS) stamping processes by means of dedicated computer-aided engineering (CAE) software requires the use of appropriate material models, the use of complex FEM models, and the use of advanced methods for solving nonlinear problems of their analysis. In practice, the engineering design of automotive body parts often leads to the formulation of problems, the solution of which requires ample computer resources and is very time-consuming. The paper describes a methodology to simulate stamping on the example of a car body part, with special attention being paid to the numerical efficiency of the FEM model and methods of solving it. The simulations of stamping of a sample stamped part—the automotive body part—in DynaForm and AutoForm programs are compared, focusing on the numerical effectiveness and consistency of the simulation results with the reality.

Torsional Vibrations of the Roller Card Doffing Comb

This paper presents the concept of a doffing comb device in a roller card based on the action of the comb shaft within the resonance area. The analysis of the vibrations of the shaft and the method for calculating its construction data have been elaborated. The rigid finite element method has been used to analyze the vibration, and the op timization method used to calculate its construction data, while its frequency of motion has been assumed. Results of the calculations are shown in a numerical example.