Temperature And Internal Pressure Bottoms Drug Structural Integrity Analysis

The research content and process of the solid propellant grain structural integrity analysis under temperature and pressure loads is discussed in this paper, and program with ability to make parametric analysis for some representative grains is made. That program is based on both C++Builder programming tool which has objective property and APDL language which is the language used in ANSYS to make advanced analysis. Discussions for propellant mechanical relaxation, linear viscoelastic models, linear viscoelastic accumulative theory, time-temperature equivalent theory and limit properties are discussed fully, because the solid propellant is a typical viscoelastic material. Since the experiential method for grain structural integrity analysis was widely used in history and is still being used in the primary design stage nowadays, it is discussed properly in this paper, and a simple program for grain structural integrity analysis is made used it. The element equations for thermal-structure analysis and viscoelastic analysis are deduced to depict the theory applied in the thermal-structure analysis and viscoelastic analysis. The process of making thermal-structure analysis and viscoelastic analysis using ANSYS is depicted in detail. The process of making the parametric analysis program using C++Builder and APDL is described in detail. At last some examples are given, on one hand to give a proven for the element method, on the other hand to give a detail description for the grain structural integrity analysis.In the work above, some are well done in this paper:1. The way to deal with the viscoelastic parameters is given. Elastic and viscoelastic items are defined separately to define the property for viscoelastic material in ANSYS. The items of shear modulus and bulk modulus which are not instantaneous are input when define the viscous items. The bulk modulus items in viscous items are not necessary to be input, when the Poison's Ratio is constant, and this means that the bulk modulus is constant. The viscoelastic parameters given in other forms need to be transferred to the form in ANSYS.2. The thermal-structure problems under unified temperature field are solved. The temperature is presumed to change in uniformity, when the duration for temperature changes is long enough, or when the stress/strain induced by temperature gradient during the cycle of temperature loads can be ignored. The presume makes the analysis more easily, but can still get acceptable results. Further more, not only can the elastic analysis be made, but also the viscoelasticanalysis can be made.3. The process of transient thermal-structure analysis is given. When the stress/strain induced by the gradient during temperature cycles needs to be known, the temperature changes inconsistently, and has gradient in space. The elastic analysis for transient thermal-structure is well made with coupling elements offered in ANSYS. The temperature distribution and corresponding elastic stress and strain can be got at any time point.4. The combined effect of temperature and pressure is made out. By defining temperature loads and pressure loads on the model at different time in the forms of load steps, the effect of them is got.5. The propellant grain structural parametric analysis is realized in primary level. The grain structural parametric program which has a very convenient interface is made with C++Builder and APDL in ANSYS. The program can make parametric analyses for typical tow dimensional grains and several simple three dimensional grains.