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Determination of Maximum Penetration Depth of Suction Caissons in Sand
Wu Yuqi,LI Dayong,Zhang Yukun,Chen Fuquan 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.8
The suction caisson is a large top-closed cylindrical steel structure in diameter, short in length and much thinner in skirt wallthickness. The total resistance of the suction caisson during installation consists of the tip resistance and the skirt wall friction. However, since the thickness of the skirt wall is very small, the skirt wall friction may produce additional vertical stress and shearstress in soil at the skirt tip level, and this additional vertical stress and shear stress will contribute to the increase in the skirt tipresistance. At the same time, seepage induced by suction also causes the tip resistance to reduce significantly. A modified slip-linefield is proposed in this study estimating the tip resistance in terms of the slip-line theory. The expression obtaining the minimumsuction to install the suction caisson is also proposed in terms of the force equilibrium. In addition, the critical suction is determinedbased on the mechanism of sand piping. Thus, the maximum penetration depth of the suction caisson can be reached when the criticalsuction equals the minimum suction. Results from calculations of the minimum suction and the maximum penetration depth havebeen proved to be in a good agreement with the measured data.
Jin Gao,Fuquan Wu,Zhixin Li 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.1
In order to study the effect of front and rear anti-roll bar’s stiffness on vehicle’s handling stability, the structure and force of the anti-roll bar are analysed, and the vehicle’s rolling model, simplified car motion model and multi-body dynamics model of a car are established. The influence of stiffness change of the anti-roll bar on understeer of the vehicle is studied by constant radius cornering simulation. In swept-sine steering input simulation, the influence of stiffness change of the anti-roll bar on the response indexes of swept-sine steering input simulation are studied, the rule of these indexes changing with stiffness of anti-roll bar is obtained. It is found at high frequencies, due to the damping effect of the system, the influence of stiffness change on yaw rate gain is opposite to that of low frequency. In step steer input simulation, the influence of stiffness change of anti-roll bar on lateral acceleration and transition time are studied. Finally, this paper matches the stiffness of front and rear anti-roll bars of the vehicle based on swept sine steering input simulation. The results show that the handling stability of the vehicle becomes relatively better after the stiffness of the anti-roll bars is matched.