Michał Majzner

Study of mechanical properties and computer simulation of composite materials reinforced by metal

In the article, two methods for testing of composite materials reinforced by sheet metal were presented. The first method is based on computer simulation of stresses in the investigated objects. It was carried out in the graphical programme NX. The second method consists in measuring deformations using strain gauge bridges and comparative analysis was carried out. The obtained results show that both methods were applied correctly and the error reaches a few percent.

Carbon fiber based composites stress analysis. Experimental and computer comparative studies

Composite materials used nowadays for the production of composites are the result of advanced research. This allows assuming that they are among the most elaborate tech products of our century. That fact is evidenced by the widespread use of them in the most demanding industries like aerospace and space industry. But the heterogeneous materials and their advantages have been known to mankind in ancient times and they have been used by nature for millions of years. Among the fibers used in the industry most commonly used are nylon, polyester, polypropylene, boron, metal, glass, carbon and aramid. Thanks to their physical properties last three fiber types deserve special attention. High strength to weight ratio allow the use of many industrial solutions. Composites based on carbon and glass fibers are widely used in the automotive. Aramid fibers ideal for the fashion industry where the fabric made from the fibers used to produce the protective clothing. In the paper presented issues of stress analysis of composite materials have been presented. The components of composite materials and principles of composition have been discussed. Particular attention was paid to the epoxy resins and the fabrics made from carbon fibers. The article also includes basic information about strain measurements performed on with a resistance strain gauge method. For the purpose of the laboratory tests a series of carbon - epoxy composite samples were made. For this purpose plain carbon textile was used with a weight of 200 g/mm2 and epoxy resin LG730. During laboratory strain tests described in the paper Tenmexs delta type strain gauge rosettes were used. They were arranged in specific locations on the surface of the samples. Data acquisition preceded using HBM measurement equipment, which included measuring amplifier and measuring head. Data acquisition was performed using the Easy Catman. In order to verify the results of laboratory tests numerical studies were carried out in a computing environment, Siemens PLM NX 9.0.For this purpose, samples were modeled composite corresponding to real samples. Tests were made for boundary conditions compatible with the laboratory tests boundary conditions.

Examination of a Cargo Space of a Freight Wagon Modified with Composite Panels

This article presents the method of solving the problem considered with the too fast wearing of a steel sheet paneling of a freight wagon body. The method, described in the work, bases on the use of additional components, which are made of composite materials. The proposed solution is based on the appropriate lining of the inside of a wagon body with composite panels. In order to verify the placing and fixing of composite panels to wagon walls, as well as to verify the behavior of joined composite panels in the given conditions of a wagon work it was used a computer analysis basing on the finite element method. Because of the scale of the analyzed problem it was also created a virtual model of the research stand, which allows experimentally verifying phenomena occurring between the joined composite panels mounted on walls of a freight wagon that is made in a natural size. Carried out researches allowed determining the method of arrangement the composite panels in the inside space of a freight wagon body. It was also determined the method of panels joining and the method of their fixing to the steel paneling of a wagon body. It was also determined the procedure of transferring the results of the experimental analysis of the wagon walls, made in a natural size, on a real object using the matching of a virtual model.

Application of Programs of the CAD/CAE Class for Creating the Virtual Laboratory Stand

The article presents the stages of creating a virtual laboratory stand for performing the cycle of tests of the system response to dynamic excitation. To create the virtual laboratory stand was used the PLM Siemens NX 8.5 software. It was shown the method of realization the dynamic analysis in the Motion Simulation module, which result was the characteristic (form) of the system excitation. Then, on the virtual laboratory stand, was conducted the analysis of vibration of the investigated system realized in the Advanced Simulation module. For calculations was used the “Response Simulation” solver, which allows analyzing the system responses to dynamic excitations. Next the results were compared with vibrations measurements made on the real laboratory stand. This lets to verify and adjust the created FEM model.

Investigations of Composite Panels Mounted in the Cargo Space of a Freight Wagon

The paper presents a series of experimental and numerical studies, carried out under the project number PBS2/A6/17/2013 realized as a part of the Applied Research Program, funded by the National Research and Development Centre. The aim of this project is to develop technology, manufacture, and assembly of composite panels on the side of a freight wagon in order to prolong the this operation. The article describes research which aimed to strength analysis of the side of the freight wagon and analysis of the behavior of structural connections of composite panels mounted on the side of the wagon. These studies were carried out on the test bench developed by the authors. During the research stresses and displacements has been analyzed at selected structural elements of the wagon before and after the modifications. The research also included an analysis of the behavior of the connections composite panels with steel components by static extortion on the side of the wagon. In parallel with the ongoing laboratory research steps have been taken to set up a FEM model by means of which was carried out similar numerical studies. Comparison of the results made it possible to adjust (tune) FEM model.

Computer Modeling and Research of FML Composites Using the Method of Features

The use of modern materials, such as composite materials, enabling the production of new or modifying the existing design solutions, and improvement of their technical characteristics in their use in the design, engineering and manufacturing process, allows achieving an improvement of their endurance, physical and chemical properties to match the features and functionality that comply with assumptions. In research studies, it has been proposed to systematize and formalize features in the context of modeling and fabrication of objects created on the basis of structural fiber composites. The result of the study and analysis will be precisely adapted algorithm of the design and construction process and also fabrication of the structural objects made upon using composite materials. The process of multicriteria optimization and stress analysis upon using CAx-class software will enable to reduce the probability of failure or damage to the modified component.

Strain Analysis of an Epoxy Resin Based Composites – Laboratory and Simulation Comparative Studies

In this paper issues of stress analysis of composite materials are presented. The components of composite materials and principles of composition has been discussed. Particular attention was paid to the epoxy resins and the fabrics made from carbon fibers. The article also includes basic information about strain measurements performed on with a resistance strain gauge method. For the purpose of the laboratory tests a series of carbon - epoxy composite samples were made. The main aim of the studies was to compare the results of two different research methods – laboratory and simulation method. During laboratory strain tests described in the paper, a composite samples were loaded with a specified load. Tenmexs delta type strain gauge rosettes were used to measure strain. They were arranged in specific locations on the surface of the samples. Data acquisition procedure were carried out using HBM measurement station. Numerical studies were carried out in a computing environment, Siemens NX 9.0. The results of simulation and laboratory tests were compared and presented in the form of graphs. They allow you to validate the method of laboratory measurements. The results of both research types have shown the percentage difference between them for individual loads applied to each composite.

Application of Computional Fluid Dynamics for Study of the Occurrence of Aerodynamic Effect for its Application in the Construction of Electric Race Car

In this article the issues related to Computional Fluid Dynamics of the occurrence of innovative aerodynamic effect were presented. Analysis were performed to determine the occurrence of Kammback aerodynamic effect and its application in a shape of a body of the real racing car in order to minimize drag forces of the vehicle. For the analysis, ideal aerodynamic shapes were modeled, subsequently they were subjected to modifications which were used to determine the occurrence of effect. The basic modeled shape was the raindrop shape solid, which is generally regarded as the ideal shape in terms of aerodynamics. The result of analysis was compared with the drag values known from the literature. Afterwards changes in the shape of the base solid were made to verify and determine the optimum Kammback shape, selected from a set of possible solutions, in which the geometrical changes has the lowest difference of values of drag force and drag coefficient Cx(Cd) in comparison to the basic raindrop shape. Results of the study were subjected to graphic analysis, especially the distribution of air pressure on the surface of a solid and in a virtual wind tunnel, distribution of the air velocity and the course of air streams around the shape. The results were used to design the body of electric race car. The main objective was to minimize the aerodynamic drag of the vehicle.

Computer Aided Analysis of Composite Structural Elements

The article presents a reflection on the definition of the feature, which enabled the development of feature-based method for modeling of composite structural components. The need for defining feature is a direct result of the ambiguity of statements or narrow definitions and their applications. So far are well developed feature, which are used in process design (CAD) - geometric feature, design feature and in the process of manufacturing (CAM) - Technology feature, and also focused on functionality (CAE - motion simulation) functional feature. The feature representation of a fully functioning feature-based system that does the aggregation of information about the structure of a construction object made from layered composites.. This approach is based on a single, independent feature representation that can be used for design, finite element analysis, technology process planning. The paper describes the main approach to the engineering analysis with the use of FEM and a convenient method of simplifying the geometry of the model and the composition of the composite. Also discussed are possible extensions to features to enhance the finite element meshing process.