The added mass coefficient and the water level index formulas for the same-phase and anti-phase vibration of rectangular liquid tanks' bulkheads were derived based on dry mode theory. Three fluid-structure interac...The added mass coefficient and the water level index formulas for the same-phase and anti-phase vibration of rectangular liquid tanks' bulkheads were derived based on dry mode theory. Three fluid-structure interaction numerical methods including Fluid FEM and Fluid BEM were used in this case. The comparison of numerical and theoretical results by the present method shows that ANSYS/Fluid80 is more credible, the NASTRAN/Virtual Mass Method is more suitable for engineering calculations and results of the same-phase vibration by the present method is more accurate.展开更多
Large Aframax product tanker(more than 100k DWT),with centerline longitudinal corrugated bulkheads and transverse corrugated bulkheads in cargo area,is the largest type of product tanker at present.The external draft ...Large Aframax product tanker(more than 100k DWT),with centerline longitudinal corrugated bulkheads and transverse corrugated bulkheads in cargo area,is the largest type of product tanker at present.The external draft of Harmonized Common Structural Rules(CSR-H)for Bulk Carriers and Oil Tankers is released for external review.More attentions are paid to the impact of CSR-H on the structural design of the corrugated bulkhead of large Aframax product tankers.Based on CSR-OT and CSR-H,it discusses the impact of CSR-H on the corrugated bulkhead by strength assessment of a 115k DWT product tanker.展开更多
Suction bucket foundations can be divided into four compartments by cruciform internal bulkheads,thereby yielding better capacity in certain conditions than those without internal bulkheads.As yet,no systematic study ...Suction bucket foundations can be divided into four compartments by cruciform internal bulkheads,thereby yielding better capacity in certain conditions than those without internal bulkheads.As yet,no systematic study has been conducted regarding the effects of cruciform internal bulkheads on the capacities of suction bucket foundations.In this study,we established a large number of finite element models of suction bucket foundations with and without cruciform internal bulkheads and of solid embedded circular foundations.We found the uniaxial capacities and failure modes of suction bucket foundations with various depth ratios to remain basically unaffected by internal bulkheads in uniform clays.However,in inhomogeneous clay with high strength heterogeneity,we observed the uniaxial moment and horizontal capacities and corresponding failure modes of suction bucket foundations with a low depth ratio to be obviously affected by internal bulkheads.In this case,the uniaxial moment capacities,in particular,as well as the horizontal capacities of suction bucket foundations with cruciform internal bulkheads become obviously greater than those without internal bulkheads.Under combined loading,we found the failure envelopes of suction bucket foundations with and without cruciform internal bulkheads and of solid circular foundation to also be basically consistent in uniform clays.However,in inhomogeneous clay with high strength heterogeneity,cruciform internal bulkheads can obviously change the shapes of the failure envelopes of bucket foundations with a small depth ratio.We conclude that when the acting vertical load or foundation depth is relatively small,suction bucket foundations with cruciform internal bulkheads can be subjected to larger moment and horizontal loads in soft clays with high strength heterogeneity.展开更多
In this paper, the stability of a concave spherical stem bulkhead under the pumping load when still lying at the slipway is analyzed. The stability of the spherical stem bulkhead with different shell thickness and rei...In this paper, the stability of a concave spherical stem bulkhead under the pumping load when still lying at the slipway is analyzed. The stability of the spherical stem bulkhead with different shell thickness and reinforcing forms is discussed. According to the results of stability analysis, the optimization design of the spherical stem bulkhead stability is performed. On the basis of considering the machining technical requirements of the bulkhead, a rational design of the spherical stem bulkhead structure is obtained. This paper has a certain value to the design of submarine's spherical stem bulkhead.展开更多
Proper regulation of the earth pressure on the bulkhead of earth-pressure balanced(EPB)shield tunneling machines is significant to ensure safe construction.This study proposes a procedure for regulating the bulkhead p...Proper regulation of the earth pressure on the bulkhead of earth-pressure balanced(EPB)shield tunneling machines is significant to ensure safe construction.This study proposes a procedure for regulating the bulkhead pressure by combining numerical simulations and data mining,and applies the procedure to a metro line constructed in sandy pebble stratum using EPB shield.Firstly,the relationship between the bulkhead pressure and the pressure on the tunnel face is carefully obtained from discrete element modeling,and the required supporting earth pressure is derived by considering the arching effect.Secondly,aided with the machine learning method,a model is constructed for predicting the average bulkhead pressure per ring according to the operational parameters(i.e.,the average driving speed and the rotation speed of the screw conveyor).Given the target value of the bulkhead pressure,the optimal values of the operational parameters are obtained from the model.In addition,an autoregressive moving average stochastic process model is developed to monitor the real-time fluctuation of the bulkhead pressure and guide the actions taken in time to avoid dramatic fluctuations.The results indicate that the pressure difference between the tunnel face and the bulkhead is considerable,and the consideration of the arching effect can avoid overestimating the bulkhead pressure.A combination of the machine learning model and the stochastic process model provides a plausible performance in regulating the bulkhead pressure around the target value without dramatic fluctuation.展开更多
[目的]探讨有/无防护舱壁结构对典型舱室在战斗部内爆下载荷及毁伤特性的影响,指导舰船重要舱室的防护设计。[方法]设计典型的双舱结构模型,以大舱室模拟爆炸当舱,小舱室模拟重要舱室,开展常规钢制舱壁与多层含液防护舱壁这2种舱室结构...[目的]探讨有/无防护舱壁结构对典型舱室在战斗部内爆下载荷及毁伤特性的影响,指导舰船重要舱室的防护设计。[方法]设计典型的双舱结构模型,以大舱室模拟爆炸当舱,小舱室模拟重要舱室,开展常规钢制舱壁与多层含液防护舱壁这2种舱室结构在6.12 kg TNT带壳装药内爆作用下的载荷及毁伤对比试验,分析破片及冲击波载荷特性,以及结构破口及变形毁伤特征。[结果]结果显示,柱锥形战斗部前端产生的破片的飞散角基本一致,且前端的破片数量少于环向破片数量;爆炸冲击波有明显的角隅汇聚特点,冲击波能量会随结构的强弱发生流向改变,整体能量更易向结构较薄弱处倾泻;在冲击波和破片的联合毁伤下,常规钢制横舱壁中心会产生大破口,而多层含液防护舱壁则仅迎弹面有较大的塑性变形及少量破片穿孔,背弹面结构完整;多层含液防护舱壁能有效阻止爆炸能量传递至邻舱,但会加剧爆炸当舱的结构毁伤。[结论]“疏堵”(舱壁加强或减弱)防护设计方法在舰船重要舱室防护中具有重要的实用价值。展开更多
基金supported by the Dalian Shipbuilding Industry Co., Ltd
文摘The added mass coefficient and the water level index formulas for the same-phase and anti-phase vibration of rectangular liquid tanks' bulkheads were derived based on dry mode theory. Three fluid-structure interaction numerical methods including Fluid FEM and Fluid BEM were used in this case. The comparison of numerical and theoretical results by the present method shows that ANSYS/Fluid80 is more credible, the NASTRAN/Virtual Mass Method is more suitable for engineering calculations and results of the same-phase vibration by the present method is more accurate.
文摘Large Aframax product tanker(more than 100k DWT),with centerline longitudinal corrugated bulkheads and transverse corrugated bulkheads in cargo area,is the largest type of product tanker at present.The external draft of Harmonized Common Structural Rules(CSR-H)for Bulk Carriers and Oil Tankers is released for external review.More attentions are paid to the impact of CSR-H on the structural design of the corrugated bulkhead of large Aframax product tankers.Based on CSR-OT and CSR-H,it discusses the impact of CSR-H on the corrugated bulkhead by strength assessment of a 115k DWT product tanker.
基金supported by the National Natural Science Foundation of China(Nos.51479133,51109157)the Elite Scholar Program of Tianjin University(2017XRG0040)
文摘Suction bucket foundations can be divided into four compartments by cruciform internal bulkheads,thereby yielding better capacity in certain conditions than those without internal bulkheads.As yet,no systematic study has been conducted regarding the effects of cruciform internal bulkheads on the capacities of suction bucket foundations.In this study,we established a large number of finite element models of suction bucket foundations with and without cruciform internal bulkheads and of solid embedded circular foundations.We found the uniaxial capacities and failure modes of suction bucket foundations with various depth ratios to remain basically unaffected by internal bulkheads in uniform clays.However,in inhomogeneous clay with high strength heterogeneity,we observed the uniaxial moment and horizontal capacities and corresponding failure modes of suction bucket foundations with a low depth ratio to be obviously affected by internal bulkheads.In this case,the uniaxial moment capacities,in particular,as well as the horizontal capacities of suction bucket foundations with cruciform internal bulkheads become obviously greater than those without internal bulkheads.Under combined loading,we found the failure envelopes of suction bucket foundations with and without cruciform internal bulkheads and of solid circular foundation to also be basically consistent in uniform clays.However,in inhomogeneous clay with high strength heterogeneity,cruciform internal bulkheads can obviously change the shapes of the failure envelopes of bucket foundations with a small depth ratio.We conclude that when the acting vertical load or foundation depth is relatively small,suction bucket foundations with cruciform internal bulkheads can be subjected to larger moment and horizontal loads in soft clays with high strength heterogeneity.
文摘In this paper, the stability of a concave spherical stem bulkhead under the pumping load when still lying at the slipway is analyzed. The stability of the spherical stem bulkhead with different shell thickness and reinforcing forms is discussed. According to the results of stability analysis, the optimization design of the spherical stem bulkhead stability is performed. On the basis of considering the machining technical requirements of the bulkhead, a rational design of the spherical stem bulkhead structure is obtained. This paper has a certain value to the design of submarine's spherical stem bulkhead.
基金supported by the National Natural ScienceFoundation of China(Grant No.41672360)Science and Technology Commission of Shanghai Munici-pality(Grant No.17DZ1203800)Shanghai Shentong Metro Group Co.,Ltd.(Grant No.17DZ1203804).
文摘Proper regulation of the earth pressure on the bulkhead of earth-pressure balanced(EPB)shield tunneling machines is significant to ensure safe construction.This study proposes a procedure for regulating the bulkhead pressure by combining numerical simulations and data mining,and applies the procedure to a metro line constructed in sandy pebble stratum using EPB shield.Firstly,the relationship between the bulkhead pressure and the pressure on the tunnel face is carefully obtained from discrete element modeling,and the required supporting earth pressure is derived by considering the arching effect.Secondly,aided with the machine learning method,a model is constructed for predicting the average bulkhead pressure per ring according to the operational parameters(i.e.,the average driving speed and the rotation speed of the screw conveyor).Given the target value of the bulkhead pressure,the optimal values of the operational parameters are obtained from the model.In addition,an autoregressive moving average stochastic process model is developed to monitor the real-time fluctuation of the bulkhead pressure and guide the actions taken in time to avoid dramatic fluctuations.The results indicate that the pressure difference between the tunnel face and the bulkhead is considerable,and the consideration of the arching effect can avoid overestimating the bulkhead pressure.A combination of the machine learning model and the stochastic process model provides a plausible performance in regulating the bulkhead pressure around the target value without dramatic fluctuation.
文摘[目的]探讨有/无防护舱壁结构对典型舱室在战斗部内爆下载荷及毁伤特性的影响,指导舰船重要舱室的防护设计。[方法]设计典型的双舱结构模型,以大舱室模拟爆炸当舱,小舱室模拟重要舱室,开展常规钢制舱壁与多层含液防护舱壁这2种舱室结构在6.12 kg TNT带壳装药内爆作用下的载荷及毁伤对比试验,分析破片及冲击波载荷特性,以及结构破口及变形毁伤特征。[结果]结果显示,柱锥形战斗部前端产生的破片的飞散角基本一致,且前端的破片数量少于环向破片数量;爆炸冲击波有明显的角隅汇聚特点,冲击波能量会随结构的强弱发生流向改变,整体能量更易向结构较薄弱处倾泻;在冲击波和破片的联合毁伤下,常规钢制横舱壁中心会产生大破口,而多层含液防护舱壁则仅迎弹面有较大的塑性变形及少量破片穿孔,背弹面结构完整;多层含液防护舱壁能有效阻止爆炸能量传递至邻舱,但会加剧爆炸当舱的结构毁伤。[结论]“疏堵”(舱壁加强或减弱)防护设计方法在舰船重要舱室防护中具有重要的实用价值。
