Thermomechanical Destruction of RubCon

Based on the conventional concept of S. Jurkov [7] that mechanical failure of a polymeric material is a process its thermochemical destruction, V. Jartsev [8] put forward the formula of the load-carrying capacity time border of a composite material based on its strength and an external temperature field. 

Two other borders of material load-carrying capacity follow from Equation (2.17). 

Formulas (2.17) and (2.18) describe the interrelation of the stress-strain state of the composite material and duration of temperature and external loading actions. Thus, for an estimation of load-carrying capacity of a composite material and its directed regulation, it is necessary to know all of the material s physical constants. For this purpose, we have undertaken experimental research at a number of preset values of the normal stresses and temperature durations of sample destruction. 

Prismatic beam samples (30 x 60 x 700 mm) of RubCon were tested for a cross, so-called pure bend, by two equal concentrated forces symmetrically located at an average third of the samples span and simultaneous temperature influence. Foading was carried out step by step to the attainment of the normal stress in the middle span of 5.7, 6.1, and 6.5 MPa. 

For creation of increased temperatures, special spiral heating elements were placed at the sides of the sample. The level of temperature heating was 60°C-105°C. During the test, loading was done after a steady temperature was attained. Temperature was controlled in a maximum stress zone. 

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