Capacity of surface warship's protective bulkhead subjected to blast loading

The protective bulkhead of the large surface warship need to be designed working in the membrane mode. In this paper, a formula is derived for calculating the plastic deformation of the protective bulkhead subjected to blast loading by the energy method, and the ultimate capability of the protective bulkhead can be calculated. The design demand of the protective bulkhead is discussed. The calculation is compared with external experiments, which indicates that the formula is of great application value.

锦州9-3油田海底管道BULKHEAD 20MnMo锻造钢与管道钢的焊接技术

BULKHEAD(锚固件)是锦州9-3油田海底管道上的重要构件,其焊接质量的优劣直接关系到原油的生产及输送。通过对国产20MnMo锻造钢与API 5L X56 管道钢的焊接性能及焊接工艺的论述,为今后类似工作提供参考。

Capacities and Failure Modes of Suction Bucket Foundation with Internal Bulkheads

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.

Calculation of the Added Mass of a Liquid Tank's Bulkheads

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.

浅析双层海底管道Bulkhead连接部位的保温计算

在双层保温管bulkhead的连接部位，由于bulkhead本身的热阻很小以及周围采用低热阻保温材料，容易形成局部低温。原油输送过程中，可能在此管段造成局部的蜡质凝聚，影响输送，因此有必要考虑施加外保温层。结合保温管道的热阻分析和有限元热传导分析，在基本设计阶段对外保温层厚度和长度进行计算。同时，考虑不同海床表面流速、海水和海床的对流换热对海管保温的影响。计算分析表明，在埋设和非埋设情况下海水对流换热对于海管保温的影响很小，在一般情况下可以忽略不计。

Comparison analysis between CSR-OT and CSR-H for corrugated bulkhead of large product tankers

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.

Research on stability design of a bar-reinforced spherical bulkhead

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.

Watertight,Bulkhead Technology of Chinese Junks

Inscribed on the List of Intangible Cultural Heritage in Need of Urgent Safeguarding in 2010.

Regulating bulkhead pressure of EPB shield machines through DEM modeling and data mining

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.

大型集装箱船甲醇燃料舱结构设计

针对甲醇作为船舶替代燃料的特点,提出一种适用于大型集装箱船的甲醇燃料舱设计方案,以一艘大型集装箱船为例,采用有限元方法来验证甲醇燃料舱区域的结构强度,同时探讨燃料舱端部节点设计对船体结构强度的影响。为大型集装箱船甲醇燃料舱的结构设计提供参考。

航空大型复杂钛框预锻成形初始毛坯优化

以某TA15钛合金框为例,采用数值模拟、响应面分析及物理模拟实验相结合的方法对预锻成形的初始毛坯形状尺寸进行了优化。构建了初始毛坯的参数化几何模型;建立了预锻成形有限元模型和响应面实验方案;以型腔各区域同时靠模为目标,根据不同初始毛坯的模拟结果,建立毛坯几何尺寸与模具型腔充填之间的定量关联关系,并通过极值求解计算出最优毛坯几何尺寸;最后采用有限元模拟和物理模拟实验验证了初始毛坯优化的可靠性和准确性。结果表明,该方法能有效克服大型复杂钛框预锻成形中常见的填充不满、成形载荷过大等问题,实现预锻件在型腔不同区域同时靠模。

深部矿山高承压应急防水闸门设计计算与数值模拟研究——以滇东北毛坪铅锌矿为例

应急防水闸门及其配套工程在水害发生时,能够在短时间内有效控制水害的影响范围和程度,保障机械设备和人员安全。随着矿山开采深度的逐年增加,应急防水闸门及闸门硐室所需要承受的水压也在不断增加,地质条件更加复杂,施工环境也更加恶劣。本文以滇东北大水矿山毛坪铅锌矿为例,在系统评价其310 m中段局部注浆改造前后突水风险的基础上,分析了深部高承压应急防水闸门设计和建造过程中的多项关键技术问题,主要包括防水闸门设计承压值计算、硐室选址、结构类型、关键结构参数、开挖围岩扰动、围岩与结构的水压响应、闸门选型与远程控制系统等。设计计算结果表明,毛坪铅锌矿310 m中段应采用倒截锥形硐室结构,对开型防水闸门,设计承压6.4 MPa。数值模拟结果表明,防水闸门硐室开挖及浇筑后,竖直和水平方向的压应力和拉应力均增大,围岩塑性破坏的范围约为0.38 m,第1个倒截锥形塞的迎水侧承担了超过80%的总水压。最后,探讨了深部高承压应急防水闸门系统的发展趋势,包括防水闸门及硐室结构长期服役的稳定性监测与评价、深部复杂地质条件下的设计与建造技术、配套智能化的水害信息辨识与预警平台等。研究结果可以为深部矿山设计和建造应急防水闸门系统提供参考和借鉴。

液氧液甲烷同温共底贮存瞬态热力特性仿真研究

针对大面积冷屏保护下的液氧/液甲烷同温共底贮箱,建立了耦合真空多层绝热与主动制冷系统的瞬态传热模型,研究了液氧/液甲烷共底自增压与零蒸发贮存过程中贮箱外部绝热结构与内部气液相的热力参数变化规律,讨论了共底夹层采用不具有绝热能力的材料对液氧/液甲烷共底零蒸发贮存特性的影响。研究结果表明,在适当的冷量输入条件下,大面积冷屏方案可以实现外界漏热的有效阻挡;采用铝合金共底夹层有利于稳定液氧和液甲烷的共底贮存状态,使液氧/液甲烷在20 h内快速达到热平衡;在零蒸发贮存周期内,液氧/液甲烷共底贮存温度波动小于0.2 K,压力波动小于2.46 kPa且具有抗热扰动的能力。

隔板对斜拉桥索塔锚固区承载力的影响分析

为研究构造内隔板对斜拉桥索塔锚固区承载力的影响分析,文中以广中江高速公路西江水道桥及其足尺试验为案例,采用ABAQUS,建立设置不同数量及厚度的构造隔板索塔锚固区的有限元模型,分析其对斜拉桥索塔锚固区承载力的影响。结果表明,在斜拉桥索塔锚固区内增设隔板可有效提高其承载能力,且屈服强度和极限承载强度随着构造内隔板的厚度增大而一定程度地增大。

宜宾新市金沙江大桥主桥总体设计

宜宾新市金沙江大桥主桥为(304+680+304)m双塔双索面钢桁梁斜拉桥,采用半飘浮体系,在桥塔横梁顶设置含限位功能的纵向阻尼器,两岸边跨各设置1个辅助墩。桥塔采用宝瓶形钢筋混凝土塔,四川岸和云南岸塔高分别为290.2 m和297.5 m,由上、中、下塔柱和上、中、下横梁及下塔柱横向连接隔板组成。主梁采用钢桁梁与钢-混组合桥面板的板桁结合型式,主桁横向中心距28 m,桁高6.8 m,标准节间长6.8 m,上、下弦杆与腹杆呈“N”形布置,采用焊接整体节点。桥面板采用钢-混组合桥面板。斜拉索采用环氧喷涂钢绞线体系,疲劳应力幅280 MPa,斜拉索在主桁上采用锚拉板锚固方式,在桥塔上采用钢锚梁锚固方式。采用桥面全回转吊机进行主桁、横桁单元件安装;钢-混组合桥面板滞后主梁2个节段施工。

隔舱式双脉冲发动机金属膜片破裂实验及数值仿真研究

针对金属隔舱式双脉冲发动机Ⅱ脉冲工作时隔舱装置金属膜片受压打开的工作特点,采用冷气冲击实验装置模拟双脉冲发动机受高压燃气冲击破膜打开的过程,建立了冷气冲击实验数值仿真模拟方法,获得了双脉冲发动机隔舱装置Ⅱ脉冲工作过程膜片的打开特性。数值仿真与冷气冲击实验中金属膜片破开时间以及破开前膜片中心结点轴向位移误差均较小,验证了2A12铝合金力学模型的准确性以及数值仿真方法的可靠性,为隔舱装置工作性能仿真分析提供了重要依据。

深海载人平台舱壁结露调温除湿方法

为降低深海载人平台任务期间舱室降温除湿产生的功率损耗,提高平台能源利用率。提出了舱壁结露以低功耗调节深海载人平台舱室温度与湿度的方法。建立了舱室热传递和含湿量模型,分析了典型工况下结露面积、风速、分段结露方式对舱内温度和湿度变化趋势的影响。结果表明:设置结露区可以实现对深海载人平台舱室温度和相对湿度的超低功耗调节;增大结露区面积可以降低深海载人平台舱室温度和相对湿度,在特定的时间段提高结露区风速可以显著降低舱室相对湿度;采用分段结露方式可以减小海水温度变化带来的舱室温度和湿度波动,使深海载人平台下潜阶段和定深作业阶段均处于合适的温度和湿度范围。舱壁结露降温除湿方法几乎零能耗且仿真计算结果显示该方法可将舱室温湿度调节至接近要求范围,为深海载人平台舱室温湿度控制技术提供参考。

双浮式挡板下液舱内液体晃荡数值分析

为有效抑制液舱内液体的晃荡,基于STAR-CCM+软件提出一种双浮式挡板结构,重点考虑在共振条件下不同淹没率、间距和高度的双浮式挡板的制荡效果。通过对比波幅、动压强极值、舱壁动压强曲线和速度矢量幅值的大小,甄选出最优的挡板结构形式。结果表明,淹没率为50%、间距D=0.32L(L为液舱的长度)、高度B_(H)=0.10 m(液舱高度H的33%)的双浮式挡板的制荡效果最好。研究结果可供后续液舱制荡设计参考。

基于HCSR描述性要求的散货船槽型舱壁优化设计

考虑到槽型舱壁的槽条参数选取通常参考母型船或由工程师凭借经验确定,采用Excel-HyperStudy联合优化模型建立了槽型舱壁的优化设计方法和流程,基于HCSR描述性规范总结槽型舱壁设计的局部强度、槽条抗弯能力、腹板抗剪切能力和腹板剪切屈曲能力方面的要求,针对槽型舱壁优化设计的关键技术即槽条布置、载荷计算点、槽型舱壁水平板缝的垂向位置、槽条的计算长度和槽型舱壁的重量计算等给出计算方法,提出使槽型舱壁重量最小的优化数学模型,建立HCSR槽型舱壁各工况的加速度、载荷和校核要求,以某散货船非风暴压载舱的槽型舱壁设计为例,建立槽型舱壁优化设计关键技术的计算方法,相比于传统方法能更准确地获取设计目标与各参数之间的相关性和重量更优的设计方案。

某型集装箱船舱壁变形原因分析及工艺优化

某国际航行集装箱船在建造过程中货舱后端壁产生褶皱变形,针对此问题进行强度校核和工艺流程两个方面的原因剖析。通过船级社规范计算和有限元校核的方法,对产生变形的舱壁在下水、强度试验等各个阶段进行结构强度分析,再与同型船施工顺序、建造工艺进行对比,得出舱壁变形是由下水和主机吊装时机不合理导致,最终提出工艺改进优化措施,有效解决了后续船舱壁变形的问题。