| The demand for high precision parts in modern industries is a new challenge for machining. Conventional machining techniques can no longer meet the requirements of high machining accuracy and low surface roughness for precision parts. Since ultra-precision machining was first introduced in the 1960s, it is widely used to fabricate precision and ultra-precision parts. However, vibration generated in the machining process has seriously affected machining accuracy and surface roughness of precision and ultra-precision machining. As a basic component for precision machine tool, machine tool bed plays an important role in bearing the stress of the machining parts and vibration attenuation. Due to its inferior vibration alleviating properties, the traditional metal materials can no longer meet the requirement of precision and ultra-precision machining. Thus, searching for a new high damping materials for machine tool bed is of important significance to promote the development of precision and ultra-precision machining and the progress of the modern industries.Resin mineral composite (RMC) is composed of organic resin with higher damping ratio, granite aggregate with higher strength and lower cost, and adds a series of some other components. RMC can be casting at room temperature, and has many advantages, such as high damping coefficient, ability to form complex shapes, and so forth. Compared with traditional metal materials for machine tool bed, applications of RMC in the field of precision and ultra-precision machine tool bed are restricted due to its limited mechanical properties.Mechanical properties of RMC have a closely relation with its components, curing techniques, air void and the interface. This paper mainly studied the effect of its components, interface, curing techniques, air void and their connection on the mechanical properties of RMC, and to study the hygrothermal aging mechanism of RMC.Aggregate type was optimized, and effect of aggregate shape on the compressive strength of RMC was investigated by the method of finite element simulation. Microstress transfer model among aggregates were established, and effect of maximum aggregate diameter and aggregate gradation on the mechanical properties was investigated. Results show that the compressive strength of RMC first increases and then decreases as the maximum aggregate diameter, the fractal dimension of the aggregate gradation increases. The primary and secondary relations of maximum aggregate diameter and aggregate gradation affecting the mechanical properties of RMC were analysed by the method of the orthogonal experiment. The effect of aggregate moisture content on the mechanical properties and its interface was analysed. In addition, the effect of surface treatment of the aggregate on the mechanical properties of RMC was systematically investigated.Stress transfer mechanism between fiber and resin matrix was established in the case of have or not the interface between fiber and resin matrix. The effect of the load, and the elastic modulus ratio of fiber and resin matrix on the axial tensile stress and interfacial shear stress were investigated by the method of finite element simulation. Considering the mechanical properties and cost of the fiber, the fiber type was optimized. And the optimal fiber length and mass content of RMC were investigated. At last, the fiber surface was treated by pretreatment, oxidation treatment, and coupling treatment. And the effect mechanism of interface between fiber and resin matrix was revealed.According to the reaction mechanism of epoxy resin and curing agent, the best mass ratio of epoxy resin and curing agent is 4:1 was obtained by combining with the method of theoretical calculation and experimental verification. The dynamic release heat of epoxy resin/curing agent system and epoxy resin/curing agent/fly ash system was obtained by differential scanning calorimeter. The kinetic triplet and the dynamic curing kinetics equation of the epoxy resin/curing agent system and epoxy resin/curing agent/fly ash system were obtained by Kissinger equation and Crane equation. And the relationship between curing degree/time, curing degree/temperature, curing rate/time, curing rate/temperature and the heating rate of differential scanning calorimeter was analysed. The best curing temperature of the two systems was obtained by the data fitting method with the independent variables is heating rate and the dependent variable is the characteristics of temperature under different heating rate. And the best curing techniques of the two systems were obtained by the method of experiment. In addition, curing techniques of RMC were optimized by the best curing techniques of the two systems.The theoretical model of a bubble rising velocity in the curing process was established by N-S equation. The effect of vibration time, the initial viscosity of resin, the height of layers, mass of compression mould, vacuum degree, defoamer on the compressive strength and air void of RMC were investigated by single-factor testing method. And the effect of water content on the compressive strength and air void of RMC and its component materials was systematically investigated. Experimental results show that the compressive strength of RMC and its component materials decreases with the increasing of the water content. However, the air void of RMC and its component materials possesses the opposite trend. The theoretical relationship between the mechanical properties of RMC and its air void deduced from the Griffith’s strength theory. Combined with the experimental data, the data fitting between the compressive strength, flexural strength, elasticity modulus of RMC and its air void was investigated. And the quantitative relationship between the mechanical properties of RMC and its air void was established.The moisture diffusion model in the material was investigated based on the Fick’s law. The moisture absorption process of RMC, granite, cured epoxy resin, and cured mixture of epoxy resin and fly ash at different temperatures was investigated by the experimental method. And the diffusion coefficient of various materials was calculated by the Fick’s law, and the accuracy of the diffusion model derived from Fick’s law in the absorption process of cured epoxy resin and cured mixture of epoxy resin and fly ash were verified. The moisture absorption process of interface between granite and resin matrix was calculated. Effect of the temperature on the mechanical properties of RMC, granite, and cured epoxy resin and the interface bond strength between granite and epoxy resin were investigated, and effect of absorption time on the mechanical properties of RMC, granite, and cured epoxy resin and the interface bond strength between granite and epoxy resin at different temperatures were also investigated. Results show that the mechanical properties of RMC, granite, and cured epoxy resin and the interface bond strength decreases with the increasing of temperature, and the mechanical properties of RMC, granite, and cured epoxy resin and the interface bond strength also decreases with the increasing absorption time at the same temperature. |
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