材料、结构和工艺因素对高强度螺栓疲劳性能的影响试验研究

对影响高强度螺栓疲劳性能的材料、结构和工艺等因素进行了较广泛的对比试验研究。比较了6种材料疲劳试样的疲劳性能;考察了硬度、再回火、去应力退火、表面脱碳、滚丝/磷化的先后顺序、头下圆角粗糙度、滚丝轮螺纹牙形、头下圆角过渡形式等因素对高强度螺栓疲劳性能的影响。     

城市道路交通噪声影响模糊评价

采用模糊综合多级评判方法评价城市道路交通环境噪声污染,其中包含了道路交通噪声对居民的实际冲击影响的综合比较评价,能够清晰地确定所测小区受噪声影响的程度,并通过实例验证了该方法的有效性和科学性。     

考虑抗力随时间变化的既有钢筋混凝土桥梁承载能力可靠度评估方法

针对既有钢筋混凝土桥梁的特点 ,讨论了结构抗力的衰减模型 ,并提出了根据已有抗力信息采用回归分析方法及最小二乘法确定或修正模型参数的方法 ;建立了以现时刻为分析时间起点的考虑抗力随时间变化的继续使用期内承载能力可靠度分析模型 ,并讨论其求解方法。应用所研究的方法对一座实际钢筋混凝土桥梁的承载能力可靠度进行了分析和评估 ,为该桥的维修加固决策提供了重要的依据     

混凝土泵车结构应力场分析与试验研究

建立了以板单元为基本单元的泵车有限元分析模型,利用MSC/NASTRAN软件对其进行了静强度分析,并进行了测试试验.计算结果与试验数据相吻合,验证了计算的正确性.找出了臂架过早出现裂纹的原因,并给出了结构改造的方法.     

基于WBS与多层次模糊综合评估的桥梁检测评估方法的研究

介绍了WBS方法在桥梁检测评估中的应用,提出了WBS方法与多层次模糊综合评估相结合的桥梁检测评估方法,并用实际工程加以了分析及验证.将WBS方法与多层次模糊综合评估相结合,使桥梁评估既便捷又科学,提高了桥梁检测评估的可靠度.     

赣江大桥公路桥病害检测与安全评估

首先对赣江大桥公路桥进行病害调查,评定全桥各部位损伤状态。根据评定结果,再对材料退化、结构损伤与受力性能进行实桥测试。应用断裂力学方法,采用观测和超声波探测方法确定初始裂纹尺寸,通过裂纹扩展模拟得出临界杆件的剩余寿命。综合实测数据与理论分析,评估该桥使用安全性和剩余寿命,并建议维护加固措施。     

Risk assessment framework for exposure of cargo and ports to natural hazards and climate extremes

There is an increase in risks and catastrophic losses in maritime transport including ports and cargo. Significant losses have been associated with large scale natural hazards, such as earthquakes, tsunami, cyclones, and other extreme weather events. This paper identifies the main gaps in understanding maritime risks in transportation research. The gaps are attributed to insufficient empirical work available from the maritime transport and logistics research community to guide multi-risk and natural hazards impact assessment on seaport and cargo. In addition, disaster studies communities have barely made adequate efforts to understand and assess port and cargo risks arising from multi-hazards and disaster events. This paper examines existing conceptual frameworks concerning exposure and risk assessments of natural catastrophe’s impacts. Furthermore, the paper identifies trends and gaps in risk assessment frameworks in the field of disaster studies that can be beneficial for maritime risk research. The authors propose a new risk assessment framework that can guide future research and multi-hazard risk assessment processes at different scales of maritime risks.     

X80管线钢管的屈强比对其失效评估曲线的影响

X80及以上级别管线钢管的高屈强比是工程应用中的一个突出问题,失效评估曲线是其安全评定的重要依据。文中通过单轴拉伸和断裂韧性试验建立了高屈强比X80管线钢管的特征失效评估图及拟合方程。结果表明：随着钢管屈强比升高,失效评估曲线的截至线（最大载荷比）降低;高、低屈强比钢管的评估曲线在载荷比大于某一临界值时发生分离,且高屈强比钢管的评估曲线处于低屈强比钢管的评估曲线之下;高屈强比钢管的选择3评估曲线比选择1和选择2曲线更偏于安全。     

How the cap limit for food-crop-based biofuels may affect France’s stakeholders by 2030? A range-based multi-actor multi-criteria analysis

From 2012 to 2016, the long-term signal in the biofuel market changed almost once per year, leading to a drastic decrease in investments and contributing to multiple production unit closures in France and around Europe. The European Commission proposed a new renewable energy directive that includes a 3.8% cap limit on the contribution of food-crop biofuels by 2030. Given the role of biofuels in green growth, the bioeconomy, and renewable energy incorporation targets, how will this measure affect the stakeholders by 2030? Will it lead to, contribute to, or hamper their sustainability criteria? This paper aims to contribute to this debate by studying the case of France. To this end, our methodology—the range-based multi-actor multi-criteria analysis—aims to (1) explicitly consider the stakeholder groups and their sustainability criteria; (2) evaluate and compare how the cap limit will affect these sustainability criteria whether or not advanced biofuels are deployed by 2030; (3) capture the uncertainty of the context evolution and biofuel capacity to fulfil the stakeholders’ sustainability criteria by means of a Monte Carlo. The results suggest that the cap limit is a double-edged sword for the stakeholders and their sustainability criteria. Shifting towards advanced biofuels while limiting the food-crop biofuels is the better alternative for most of the stakeholders. Nevertheless, given biofuel policy instability and the lost confidence of investors, such a shift may not occur by 2030. In such a case, this paper demonstrates that the cap limit may highly and negatively affect the stakeholders and their sustainability targets, whereas fostering French food-crop biofuel production at its full capacity level constitutes a better alternative. As no alternative is suited to all actors simultaneously, this paper also studies the strengths and weaknesses of these alternatives from each stakeholder groups’ perspective.     

Fitness-for-purpose assessment of cracked offshore wind turbine monopile

In this paper, the procedure for flaw acceptability assessment is examined through a case study of a semi-elliptical surface crack in an offshore monopile as it grows till it forms a through thickness crack. Using the procedure prescribed in an industrial standard (BS 7910), the fracture ratio, K_r is shown to increase monotonically with increasing crack depth. The load ratio, L_r, is initially insensitive to the crack depth. However, there is a rapid increase in L_r when the crack depth to thickness ratio exceeds 80%. L_r values obtained from detailed 3D FE limit analysis using elastic-perfectly-plastic material behaviour do not exhibit the asymptotic behaviour predicted by BS 7910 as the flaw transitions from deep crack to through-thickness crack. Furthermore, K_r predicted by BS 7910 is shown to be an over-estimation for the typical dimensions of offshore monopiles. The findings suggest that a structure with a deep flaw may be identified as unacceptable based on BS 7910 when it may still possess a non-trivial amount of structural residual life. This is a concern for monopiles where crack growth as a large flaw forms a significant part of the total life.