Study On Fiber Reinforced Polymer Concrete And Its Interface And Damping Mechanisms

The development and rapid progress of precision and high-precision machining technology expect machine tools to provide higher machining precision. The structural materials for elementary machine parts have enormous influence on the machine tools' properties, especially machining precision. To explore new types of materials for elementary machine parts is one of the most effective ways to improve the over-all properties of the machine tools. As far as vibration alleviating properties is concerned, Polymer Concrete (abbreviated as PC) is favorable. Machining precision would be improved significantly if elementary machine parts are made of polymer concrete. Therefore, polymer concrete has attracted extensive attention from the researchers in the relevant field.In this thesis, glass fiber and carbon fiber are applied in polymer concrete for the first time. Glass fiber reinforced polymer concrete (abbreviated as GFRPC) and carbon fiber reinforced polymer concrete (abbreviated as CFRPC) are developed and applied as elementary machine parts. Polymer concrete reinforced with glass fiber or carbon fiber could also be referred as fiber reinforced polymer concrete (abbreviated as FRPC).Systematical studies were carried out for the mechanisms of fiber reinforced polymer concrete, such as components' characteristics, forming processes, interface action mechanism, damping mechanism and mechanical properties, etc, meanwhile, a proper forming and production process for fiber reinforced polymer concrete is proposed. Interface mechanism among the components is analyzed, chemical model and physical model about the interfacial bonding were built based on the analysis. Damping and vibration alleviating properties of fiber reinforced polymer concrete were also analyzed, meanwhile, calculation models about damping loss factor and damping ratio were created. How the factors such as proportion of the components and forming process affect mechanical properties of fiber reinforced polymer concrete is studied, which provides basis for the optimization of the components' proportions and improvement of the composite's properties.Raw materials are important factors that determine properties of fiber reinforced polymer concrete. Physical and chemical properties of the raw materials for fiber reinforced polymer concrete were studied in this thesis. Epoxy resin was selected as binder and corresponding stabilizer, flexibilizer and other relevant agents were determined. Solidification mechanisms of epoxy resin under the presence of stabilizers is described in details. Requirements for aggregate frameworks and strengthening fibers as well as the ones used frequently were introduced, also, the proper components were determined.On the basis of theoretical analysis, production process of fiber reinforced polymer concrete of fiber reinforced polymer concrete was studied through experiments. The following processes were described in details: surface treatment of strengthening fibers, forming process of fiber reinforced polymer concrete, maintenance of the semi-finished products, choice of the mold releasing agent, designing principles of elementary machine parts made of fiber reinforced polymer concrete, as well as the consequent machining processes of finished products. A technological process system for fiber reinforced polymer concrete is established, which covers the scope from the treatment of raw materials to production of the materials and the designing of product structures.The interfacial action mechanism of fiber reinforced polymer concrete was studied. A model about the chemical bonds between strengthening fibers and epoxy resin matrix, as well as another model about the interface physical actions between granite aggregates and epoxy resin matrix were created. Some active radicels formed on the surface of strengthening fibers, which could react with epoxy radicels or any other radicels inside epoxy resin matrix. Chemical bonds could be built after the reactions between strengthening fibers and epoxy resin matrix, which would make them as a whole with the high chemical bond energy. Interface between granite aggregates and epoxy resin matrix is built through the surface soakage between liquids and solids, as well as the mechanical keying actions between granite aggregates and solidified epoxy resin matrix. Interfacial combination between the two phases is realized by interface energy, the Van Der Walls' force among molecules and mechanical interactions.The damping and vibration alleviating mechanisms of fiber reinforced composites were studied, also, the main source and influencing factors for the damping properties of fiber reinforced polymer concrete were analyzed. Calculation models for damping loss factor and damping ratio were presented. The main source for the damping properties of fiber reinforced polymer concrete comes from damping of the composite matrix, including epoxy resin matrix, granite aggregates and strengthening fibers. Damping caused by other factors (interface damping, thermo-elasticity damping, viscoelasticity damping and damping caused by the material rupture) also has some influences on damping properties of the composites. Two groups of orthogonal tests were designed to review how the components' proportions fiber type affect the composite's damping properties. Trend curves which show how the different factors affect damping properties of the composite were obtained on the basis of the experimental results.How the components' proportions affect mechanical properties (taking compression strength as the judging index) of fiber reinforced polymer concrete was studied through orthogonal tests. Trend curves which show how experimental factors affect mechanical properties of the composite would be obtained on basis of the analysis of experimental results. Then the affection of the factors on the mechanical properties of the composite was obtained based on the curves, which could be applied to determine the components' proportions. The differences between mechanical properties of glass fiber reinforced polymer concrete and carbon fiber reinforced polymer concrete, as well as the effect of fiber length and fiber dosage on mechanical properties of fiber reinforced polymer concrete was studied through another series of orthogonal tests. The strength of carbon fiber is better than that of glass fiber, so that it could bear more stress inside the composite matrix, as a result, the strengthening effect of carbon fiber in polymer concrete matrix is better than that of glass fiber.