混凝土裂缝成因分析及防治建议

通过对混凝土裂缝产生的原因进行分析,提出现场混凝土温度的控制和裂缝预防措施,可供相关工程项目参考和借鉴。     

CKA-C型外锁闭装置动力学特性试验研究

在宁波地铁轨道测试线道岔上,安装了CKA-C型外锁闭装置进行行车试验,采集基本轨、尖轨连接铁、锁闭框、锁钩和锁闭杆的动力学响应数据,通过分析加速度信号的频谱及结构件所承受的应力,评估产品的安全性和可靠性。试验结果表明CKA-C型外锁闭装置能够满足使用需要,且具有较大的安全余量;产品的固有频率也避开了行车的特征频率,不会产生共振。     

大体积混凝土施工过程中的裂缝防治

现代建构筑物中的裂缝一旦生成,将直接影响结构的使用寿命,甚至会导致结构破坏.结合工程实例分析大体积混凝土裂缝的防治措施,对指导实际工作有一定的意义.     

A simple surrogate model for the rainflow fatigue damage arising from processes with bimodal spectra

There are many applications, in particular offshore engineering, in which the load process comprises a high frequency and a low frequency component, and each component can be regarded as a narrowband process. Many researchers have proposed spectral methods for evaluating the rainflow fatigue damage for such bimodal processes, nevertheless the accuracies of these methods still have room for improvement. Recently, the author has developed an analytical approach that compares well with numerical simulation; unfortunately, the approach is intricate and difficult to implement. This paper presents a new formula that is accurate, and yet simple enough for adoption in standard spreadsheets and design codes. The formula is valid for a wide range of parameter values and yields the exact theoretical result under several limiting conditions. The formula is calibrated based on extensive numerical simulations, and the database of results are fully presented herein so that they may be used directly in design, or for further studies.     

某型船用柴油机机体装配台肩裂纹原因分析及对策

文章针对某型船用柴油机机体装配台肩多处裂纹，在常规应力分析计算的基础上，考虑安全性、经济性，提出了一种有效的解决方法，该船柴油机经3年使用正常。     

大体积混凝土裂缝成因及防治措施

控制和预防大体积混凝土裂缝是一项系统工程,涉及到设计、原材料的选择、施工工艺、养护和其他一些不确定的因素。对大体积混凝土裂缝成因进行系统的理论研究,提出合理的裂缝控制措施,可为工程实践提供指导。     

唐港高速公路桥涵常见病害及处治措施

根据唐港高速公路桥涵定期检查结果，结合该高速公路通车多年的实际情况以及其他高速公路的养护经验，对唐港高速公路桥涵提出了养护建议及保障措施，以更好地保障桥涵运营质量。     

桥梁混凝土结构裂缝控制探讨

在桥梁混凝土结构中,裂缝是最常见的病害,这一病害使工程的质量大打折扣。鉴于此,分析总结桥梁混凝土裂缝产生的原因,并提出解决措施,以防止混凝土裂缝带来的不良后果,提高桥梁工程的质量。     

预防和降低船上疲劳的“STEP”机制

该文通过综合分析业界有关研究成果和国际海事组织关于船上疲劳的有关导则手册,梳理当前普遍认同的导致船上疲劳的因素并结合实际分析在预防和降低船上疲劳的过程中所面临的障碍,有针对性地提出从社会(Society)、技术(Technology)、经济(Economy)和政策(Policy)层面共同着手建立关于预防和降低船上疲劳的“STEP”机制。     

The use of operational modal analysis and mode tracking for insight into polar vessel operations

Accurate dynamic models of flexible ship structures are required to predict structural vibration caused by environmental loads. Knowledge of dynamic or modal properties are important, for example, to study fatigue damage. In this paper, operational modal analysis (OMA) is used to identify the vibration characteristics of a polar vessel from full-scale acceleration measurements. Five modes are tracked over a range of different operating and environmental conditions, including calm, open water, two ice cases and an open water storm. Compared to the calm, open water conditions, vertical bending modes were generally affected the most by the operating environment, with natural frequency and damping increasing up to 3.7 and 349 %, respectively, in ice. Severity of two-node and three-node vertical bending responses, quantified using a root-mean-square value, were found to be especially large during the open water storm case. Temporal behaviour of two-node and three-node vertical bending due to wave-slamming further contained multiple whipping responses, pointing towards possible cumulative damage over a large number of stress cycles occurring at the midship. Higher damping in ice resulted in responses with lower magnitudes and shorter durations.