This study applies a double snap-through mechanism on a box-type oscillating buoy(OB)wave energy converter(WEC)-floating breakwater integrated system(OB WEC-FB)to simultaneously achieve efficient wave energy conversio...This study applies a double snap-through mechanism on a box-type oscillating buoy(OB)wave energy converter(WEC)-floating breakwater integrated system(OB WEC-FB)to simultaneously achieve efficient wave energy conversion and nearshore protection within a low-frequency bandwidth.This mechanism consists of four oblique springs and can operate in mono-stable,bi-stable,and tri-stable modes.A viscous-flow-based numerical model is established to investigate the hydrodynamic performance and dynamic behavior of the proposed multi-stable breakwater.The operational performance of the breakwater at different dynamic modes is first compared.The effects of the springs’original length and stiffness coefficient are then analyzed.The results show that the tri-stable breakwater has a wider resonance frequency tuning range than the bi-stable one,both of which outperform the mono-stable and linear ones in shifting the effective bandwidth to a lower frequency range.For a tri-stable breakwater,a large distance between outermost potential wells is conducive to tuning resonance frequency,whereas shallow potential wells limit this effect.The increase in spring stiffness distinctly causes a higher potential barrier and thus constrains the motion response of the breakwater.A well-designed double snap-through mechanism can excite large-amplitude inter-well motion,tune the resonance frequency of breakwater from 3.98 to 1.96 rad/s,and decrease the lower limit of the effective transmission bandwidth from 3.75 to 3.00 rad/s.It is crucial for improving the power absorption and wave attenuation capabilities of multi-stable OB WEC-FB.This study contributes to the limited research on the implementation of a double snap-through mechanism on multifunctional marine structures.It establishes the underlying connection between nonlinear dynamic behaviors and hydrodynamic coefficients.展开更多
文章采用combined C-H构建了5182铝合金0.85 mm厚板材的材料模型,基于Deform软件建立了自冲铆SPR搭接结构(0.85 mm 5182/2 mm 5754)模型,并以接头互锁值和底厚值为目标对模型进行了验证,模型分析误差在5%以内。基于该铆接模型开展了518...文章采用combined C-H构建了5182铝合金0.85 mm厚板材的材料模型,基于Deform软件建立了自冲铆SPR搭接结构(0.85 mm 5182/2 mm 5754)模型,并以接头互锁值和底厚值为目标对模型进行了验证,模型分析误差在5%以内。基于该铆接模型开展了5182合金上板屈服强度、抗拉强度和加工硬化指数对铆接接头质量的影响规律研究。结果表明,接头互锁值U随板材屈服强度的增加而增加,随抗拉强度和加工硬化指数的增加而降低;底厚值Tmin随材料力学性能的提高而增加。三因子对底厚值的影响顺序为,抗拉强度(k_(σs)(0.00269))<加工硬化指数<屈服强度影响(k_(σb)(0.00378))。展开更多
目前,基于高速电力线通信(high speed power line communication,HPLC)技术的传统抄表方案最快只能采集15 min的冻结数据,无法满足电力物联网所需分钟级数据的要求。为实现分钟级实时数据采集,对传统采集方案提出改进方案:首先,在站点(s...目前,基于高速电力线通信(high speed power line communication,HPLC)技术的传统抄表方案最快只能采集15 min的冻结数据,无法满足电力物联网所需分钟级数据的要求。为实现分钟级实时数据采集,对传统采集方案提出改进方案:首先,在站点(station,STA)应用层增设采集任务模块,使STA存储电表实时数据并按采集任务将其上传;其次,将集中器与中央协调器(central coordinator,CCO)模块之间的通信方式替换为以太网通信,并增设CCO应用层收发子层模块,用以克服传输速度瓶颈;最后,将Q/GDW1376.2通讯协议更替为DL/T698.45协议,使得从主站到站点的通讯协议规范统一,提高单帧数据的有效数据占比。实验室模拟以及现场在线台区测试结果表明:新的采集效率优化方案可实现采集现场台区5 min冻结数据,且上传时间维持在70 s内,可在相同采集时间段内获得更多电力数据,为泛在电力物联网的业务开展建立了数据基础。展开更多
基金supported by the National Natural Science Foundation of China Program(No.51739010).
文摘This study applies a double snap-through mechanism on a box-type oscillating buoy(OB)wave energy converter(WEC)-floating breakwater integrated system(OB WEC-FB)to simultaneously achieve efficient wave energy conversion and nearshore protection within a low-frequency bandwidth.This mechanism consists of four oblique springs and can operate in mono-stable,bi-stable,and tri-stable modes.A viscous-flow-based numerical model is established to investigate the hydrodynamic performance and dynamic behavior of the proposed multi-stable breakwater.The operational performance of the breakwater at different dynamic modes is first compared.The effects of the springs’original length and stiffness coefficient are then analyzed.The results show that the tri-stable breakwater has a wider resonance frequency tuning range than the bi-stable one,both of which outperform the mono-stable and linear ones in shifting the effective bandwidth to a lower frequency range.For a tri-stable breakwater,a large distance between outermost potential wells is conducive to tuning resonance frequency,whereas shallow potential wells limit this effect.The increase in spring stiffness distinctly causes a higher potential barrier and thus constrains the motion response of the breakwater.A well-designed double snap-through mechanism can excite large-amplitude inter-well motion,tune the resonance frequency of breakwater from 3.98 to 1.96 rad/s,and decrease the lower limit of the effective transmission bandwidth from 3.75 to 3.00 rad/s.It is crucial for improving the power absorption and wave attenuation capabilities of multi-stable OB WEC-FB.This study contributes to the limited research on the implementation of a double snap-through mechanism on multifunctional marine structures.It establishes the underlying connection between nonlinear dynamic behaviors and hydrodynamic coefficients.
文摘文章采用combined C-H构建了5182铝合金0.85 mm厚板材的材料模型,基于Deform软件建立了自冲铆SPR搭接结构(0.85 mm 5182/2 mm 5754)模型,并以接头互锁值和底厚值为目标对模型进行了验证,模型分析误差在5%以内。基于该铆接模型开展了5182合金上板屈服强度、抗拉强度和加工硬化指数对铆接接头质量的影响规律研究。结果表明,接头互锁值U随板材屈服强度的增加而增加,随抗拉强度和加工硬化指数的增加而降低;底厚值Tmin随材料力学性能的提高而增加。三因子对底厚值的影响顺序为,抗拉强度(k_(σs)(0.00269))<加工硬化指数<屈服强度影响(k_(σb)(0.00378))。
文摘目前,基于高速电力线通信(high speed power line communication,HPLC)技术的传统抄表方案最快只能采集15 min的冻结数据,无法满足电力物联网所需分钟级数据的要求。为实现分钟级实时数据采集,对传统采集方案提出改进方案:首先,在站点(station,STA)应用层增设采集任务模块,使STA存储电表实时数据并按采集任务将其上传;其次,将集中器与中央协调器(central coordinator,CCO)模块之间的通信方式替换为以太网通信,并增设CCO应用层收发子层模块,用以克服传输速度瓶颈;最后,将Q/GDW1376.2通讯协议更替为DL/T698.45协议,使得从主站到站点的通讯协议规范统一,提高单帧数据的有效数据占比。实验室模拟以及现场在线台区测试结果表明:新的采集效率优化方案可实现采集现场台区5 min冻结数据,且上传时间维持在70 s内,可在相同采集时间段内获得更多电力数据,为泛在电力物联网的业务开展建立了数据基础。
