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  • THE CALCULATION AND ANALYSIS OF FLEXIBLE JOINT ADHESION BONDED INTERFACE’S J-INTEGRAL IN SOLID ROCKET MOTOR

    Paper number

    IAC-08.C4.3.11

    Author

    Mr. baolin sha, China

    Year

    2008

    Abstract

    Flexible nozzle plays an important part in solid rocket motor, such as converting energy,controlling thuster ect. Flexible is a key part one in nozzle, which is made of front flange, back flange, elastomer layer , reinforcement layer. During the movable nozzle with flexible bearing of SRM useful life, main failure mode is debonded on the bondline of flexible joint,its lead to gas leakage.Because multiplayer bonded interface (rubber) exists in the flexible joint, it is difficult to check the failure mode .so the characterize and anlysis method in multiplayer bonded interface must be developed in practice. a equipment is developed: advanced Double Lap. adhesion test. as the Fig 1 showns,

    Fig 1 adhesion test speciment The structure made of bonded dissimilar materials,the interface crack-tip stress intensity , including module and phase angle.factors K1 and K2 are defined in a following complex form: k=k1+ik2 (1) for elastic media,J-K relationship: J=(c1+c2)/16cos(h*h(πε)) (2) MARC soft offer a effect measure: 1/4 singularity unit method. the measure has a good accuracy in the crack-tip’s zone. its can also calculate J-integral through the dates of the crack face’s displacement by hand. which can also get the J-integral and strain energy every loading step through MARC. Attain J-integral from different size interface crack ,which can get the relation between the length of the crack and the capability of resisting loading for a component. its shown the length of the crack are so sensitive to the loading,in order to described the phenomena,so sensitivity coefficient of interface crack is introduct:,it defined as: Θ=1-Ja/J0 € interface sensitivity coefficient Ja J-integral of a mm length crack

    J0 can get with extrapolation methods: for a given set of data points?a?Ja?,use for the method linear least squares to data fitting, can get a line, the J0 is the crosspoint between the line and y axis. some usefull result get: (1) The J-integral and k factor through two different methods, they have a good consistences. (2) Different length of crack have different capability of resisting loading, sensitivity coefficient of interface crack is a good measurement.

    Keywords: flexible joint, bonded interface, adhesion test, ,solid rocket motor(SRM) , crack

    Abstract document

    IAC-08.C4.3.11.pdf

    Manuscript document

    IAC-08.C4.3.11.pdf (🔒 authorized access only).

    To get the manuscript, please contact IAF Secretariat.