random fatigue life prediction due to vibro-acoustic and thermal environments
- Paper number
IAC-08.C2.1.7
- Author
Mr. Pietro Carlo Marucchi Chierro, Thales Alenia Space Italy, Italy
- Coauthor
Mr. Massimo Antonacci, Thales Alenia Space Italy, Italy
- Coauthor
Mr. Savino De Palo, Thales Alenia Space Italy, Italy
- Coauthor
Mr. Stefano Destefanis, Thales Alenia Space Italy, Italy
- Year
2008
- Abstract
During the Launch and entry phases re-entry vehicles are submitted to heavy vibro-acoustic and thermal environments. Various design approach for predicting the random fatigue life of structural items (TPS, Structures…) have been proposed and developed. These methods generally include predicting the random loads, estimating the fluctuating stress response of the structures and predicting the life from stress versus cycles to failure curves for the relevant metallic material. As the vibro-acoustic and thermal environments increase, the induced stress response and the structures fatigue behaviour become more non linear and very difficult to predict with the classical computation methods, because the theory of non linear random vibration has not reached a good state of maturity. Moreover, the fatigue process which reduce strength in composite materials are generally very complex, involving the accumulation of multiple damage modes which may combine in a variety of way to produce numerous failure modes. The derived stress levels in rms form for particular load cases are used together with rms stress endurance data to estimate fatigue damage for each case. The overall structural damage can then be used to obtain the fatigue life of the relevant component. A probabilistic model for damage accumulation in composite is therefore the most suitable one. Consequently, probabilistic concepts and methods are needed for an assessment of the safety and reliability of metallic and composite under fatigue. By both the CEE - BRITE EURAM RESEACH “AMADEUS” and a dedicated ESA study on “Health management system for reusable space transportation”, an analytical formulation based on a statistical method has been proposed to evaluate the “expected” fatigue damage on structures subjected to random loads during their service life. The target of the present paper is to show the reliability of the simulation techniques based on Finite Element Method (FEM) and the statistical Energy Analysis (SEA) modelling, adopted for the derivation of spacecraft Random Vibration Environment (RVE) integrated with a newly developed algorithm to predict the multi-axial Random fatigue for structural panels models. Moreover MATLAB simulink models for TPS and Structure have been developed for the Health monitoring and Health management purposes. Based on this Design verification approach, the potential Design criticality can be identified in the early design stage of a project and where required local structural modifications can be implemented during the development phase, resulting in an optimized design at reduced cost.
- Abstract document
- Manuscript document
IAC-08.C2.1.7.pdf (🔒 authorized access only).
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