A buffer bag mechanism is designed, which can provide axial impact protection under small displacement. The stiffness characteristics of the structure under impact load are studied.The stiffness of the mechanism and the internal pressure change of the buffer bag are compared and analyzed, when the filling materials are liquid and gas respectively. Finally, the influence of initial fluid bag pressure, bulk modulus and shell thickness on the stiffness of the mechanism and the change of bag pressure are studied. The results show that the stiffness of the liquid bag is better than that of the gas bag when the filler is liquid and gas; the liquid bag has obvious pressure rise after the mechanism is subjected to axial force by 300 kN, and the gas bag has almost no pressure rise; the change of bulk modulus, which is 1 000, 1 500, 2 000 and 2 500 MPa, has an obvious effect on the liquid bag, and it is positively correlated with the stiffness of the mechanism. The change of gas modulus, which is 28 and 44, has little effect on the stiffness of the mechanism; the thickness of the buffer bag, which is 5, 10 and 15 mm, also has an obvious effect on the stiffness. The stiffness of the liquid bag is greater, and the protection for flexible joint is better in the same condition.
HOU Yu, ZHANG Ming, NIE Hong. Influence of Different Filling Materials on Stiffness of a New Buffer Bag[J]. Transactions of Nanjing University of Aeronautics & Astronautics,2021,38(1):106-116
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History
Manuscript received: November 19,2020
Manuscript revised: January 17,2021
Adopted:
Online Published: February 25,2021
Published:
表 2 Table 2 Mesh independence test
图1 Buffer bag shock absorption mechanismFig.1
图2 Schematic of buffer bag and its simplified modelFig.2
图3 Coupling whit fluid cavity methodFig.3
图4 Master surface and slave surface for the first contact pairFig.4
图5 Master surface and slave surface for the second contact pairFig.5
图6 External input curveFig.6
图7 Finite element modelFig.7
图8 Stress map of the gas bag and displacement map of the flexible jointFig.8
图9 Stress map of gas bag dynamic processFig.9
图10 Maximum stress curve of gas bag elementFig.10
图11 Stress map of liquid bag and displacement map of flexible jointFig.11
图12 Stress map of fluid bag dynamic processFig.12
图13 Maximum stress curve of liquid bag elementFig.13
图14 Simulated and experimental distance of gas bag and liquid bagFig.14
图15 Influence of initial pressure of buffer bagFig.15
HOU Yu, ZHANG Ming, NIE Hong. Influence of Different Filling Materials on Stiffness of a New Buffer Bag[J]. Transactions of Nanjing University of Aeronautics & Astronautics,2021,38(1):106-116
HOU Yu, ZHANG Ming, NIE Hong. Influence of Different Filling Materials on Stiffness of a New Buffer Bag[J]. Transactions of Nanjing University of Aeronautics & Astronautics,2021,38(1):106-116
HOU Yu, ZHANG Ming, NIE Hong. Influence of Different Filling Materials on Stiffness of a New Buffer Bag[J]. Transactions of Nanjing University of Aeronautics & Astronautics,2021,38(1):106-116
HOU Yu, ZHANG Ming, NIE Hong. Influence of Different Filling Materials on Stiffness of a New Buffer Bag[J]. Transactions of Nanjing University of Aeronautics & Astronautics,2021,38(1):106-116
HOU Yu, ZHANG Ming, NIE Hong. Influence of Different Filling Materials on Stiffness of a New Buffer Bag[J]. Transactions of Nanjing University of Aeronautics & Astronautics,2021,38(1):106-116
HOU Yu, ZHANG Ming, NIE Hong. Influence of Different Filling Materials on Stiffness of a New Buffer Bag[J]. Transactions of Nanjing University of Aeronautics & Astronautics,2021,38(1):106-116
HOU Yu, ZHANG Ming, NIE Hong. Influence of Different Filling Materials on Stiffness of a New Buffer Bag[J]. Transactions of Nanjing University of Aeronautics & Astronautics,2021,38(1):106-116
HOU Yu, ZHANG Ming, NIE Hong. Influence of Different Filling Materials on Stiffness of a New Buffer Bag[J]. Transactions of Nanjing University of Aeronautics & Astronautics,2021,38(1):106-116