Effect of Rheological Properties of the Composite on Stress-Strain Behaviour of Moulded Structure

Civil engineering is an integral part of the effective use of polymeric composite materials. A promising direction is to use composites for the strengthening of reinforced concrete structure. Solidity of these products, their structure and accuracy of making the repair is largely associated with the manifestation of residual technological stresses, which occur during moulding. The paper deals with the study of stress–strain behaviour of the moulded composite structure in the process of its cooling. It is shown that both physico-mechanical characteristics of materials and rheonomic properties of the moulded product should be taken into account when the cooling stage is designed. Analytical dependences of the effect of rheonomic properties on the stress–strain behaviour of the moulded composite package at the cooling stage have been obtained. These dependences also allow calculating the process parameters of stepwise cooling stage. It is demonstrated that the phenomena of creep and relaxation in the structure at the cooling stage may lead to increase in the process-induced deformations and reduction of stresses in the moulded product. The method for determination of the moulding process parameters (temperature, time) which provide the regulated stress–strain behaviour of the structure has been developed. The results allow improving the accuracy of calculations of process-induced stresses and deformations and providing an additional opportunity to optimize the cooling mode (choosing of temperature holding time) for the reduction of residual stress and deformation level.