Analysis Of Mechanical Behavior Of Linerless Composite Tank Under Thermal-Mechanical Coupling Load

Cryogenic propellant tanks are not only the core component of space vehicles, but also the source of energy for engine of space vehicles, In order to reduce launch costs, improve carrying capacity, space vehicle is developing in the direction of large-scale and lightweight, using of linerless composite propellant tank has a far-reaching strategic significance. However, linerless composite tanks are generally working at cryogenic temperature, thermally induced matrix cracking can easily happen, as a result of the leakage of liquid fuel could leading the catastrophic failure of whole structure. Therefore, the safety requirements should be very high. But no method currently available has shown the ability to predict failure of the linerless composite tanks at cryogenic temperature.At first, this paper introduced the unit cell finite analytical model of composites, different matrix cracking failure criterion were selected, and the predicted results for matrix cracking of composite laminates at cryogenic temperature between different failure criterions were compared, the most suitable failure criterion has been chosen for composite failure analysis at cryogenic temperature. Then, this paper proposed a progressive damage analysis method of composites based on unit cell finite analytical model, implemented integrated analysis consist of trans-scale structural response and progressive damage of composites. Typical examples are presented to demonstrate the necessity and superiority of progressive damage analysis method of composites based on unit cell finite analytical model. At last, progressive damage analysis of linerless composite tank has been conducted. The example analyzed the damage evolution and ultimate bearing capacity of linerless composite tank when use traditional progressive damage analysis method and progressive damage analysis method based on unit cell finite analytical model, and discussed the effects of considering the thermodynamic properties of the material vary with temperature to ultimate bearing capacity of linerless composite tank.