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1.
用SZ法测试焊缝金属延性断裂韧度的研究   总被引:6,自引:0,他引:6  
采用SZ法对焊缝金属的延性断裂韧度进行了测定并作了线性回归分析,分析了SZ法的特点,并对其关键技术作了探讨。最后建议对于高延性采用SZ法,用实测钝化线与阻力曲线的交点所对应的延性断裂韧度值作其临界值。  相似文献   

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采用SZ法对焊缝金属的延性断裂韧度进行了测定并作了线性回归分析,分析了SZ法的特点,并对其关键技术作了探讨。最后建议对于高延性材料采用SZ法,用实测钝化线与阻力曲线的交点所对应的延性断裂韧度值作其临界值。  相似文献   

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R曲线法在焊缝金属延性断裂韧度测试中的应用研究   总被引:1,自引:0,他引:1  
测定了不同焊接线能量条件下60 kg级熔敷金属的JR阻力曲线和COD阻力曲线,得出了线能量对Jc、δc的影响规律.在实验范围内熔敷金属延性断裂韧度随焊接线能量增加而增大.总结了两种阻力曲线的各自特点以及产生实验误差的原因.相比较而言,JR曲线法在曲线回归时数据相关性更高,更精确.  相似文献   

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船用钢板焊缝的金属磁记忆检测技术原理与应用   总被引:2,自引:0,他引:2  
本文简要介绍金属磁记忆检测技术(MMT)的原理和在船用钢板对接焊缝及其局部母材质量检测中的应用。  相似文献   

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测定了不同焊接线能量条件下60kg级熔敷金属的JR阻力曲线和COD阻力曲线,得出了线能量对Jc、δc的影响规律。在实验范围内熔敷金属延性断裂韧度随焊接线能量增加而增大。总结了两种阻力曲线的各自特点以及产生实验误差的原因。相比较而言,JR曲线法在曲线回归时数据相关性更高,更精确。  相似文献   

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由于高强度钢的使用,船舶结构许用应力水平的提高,船舶结构的疲劳强度越来越受到关注。船舶结构的疲劳寿命取决于其焊接结构的疲劳寿命。因此,了解焊缝几何参数对焊件疲劳强度的影响以及采用经济实用的方法改善船舶结构的疲劳性能是十分重要的。本文首先对焊缝几何参数对焊件疲劳寿命的影响进行了分析,在此基础上用ABS钢和945钢两种钢板做试件,分别进行了简单拉伸实验及打磨和未打磨条件下对接接头的疲劳试验。试验结果表明焊件的疲劳寿命可以通过打磨焊缝得到改善;尤其对于高强度钢焊件。试验还说明手工打磨焊缝和机械磨削焊缝对焊件疲劳强度的改善效果差别很大,疲劳寿命的分散性也很大。因此,应当对改善焊件疲劳寿命的工艺进行更详细的研究。  相似文献   

8.
对船用EH36钢的焊缝和热影响区在-20C下的临界CTOD进行测试,以评定其断裂行为。发现焊缝的断裂韧性较差,容易脆性断裂,建议调整熔敷金属的化学成分,来提高焊缝低温抗断裂性能;热影响区的临界CTOD值较高,受焊接热影响较小。  相似文献   

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利用H10Mn2焊丝和SJ101焊剂匹配焊接14MnNbq钢,通过系列温度示波冲击韧性试验,模拟不同焊接条件下的工艺试验,找到焊接接头强韧性的工艺措施和最佳焊接工艺参数.  相似文献   

11.
The use of a glass-fiber reinforced composite in marine structures is becoming more common, particularly due to the potential weight savings. The mechanical response of the joint between a glass-fiber reinforced polymer(GRP) superstructure and a steel hull formed is examined and subsequently modified to improve performance through a combined program of modeling and testing. A finite-element model is developed to predict the response of the joint. The model takes into account the contact at the interface between different materials, progressive damage, large deformation theory, and a non-linear stress-strain relationship. To predict the progressive failure, the analysis combines Hashin failure criteria and maximum stress failure criteria. The results show stress response has a great influence on the strength and bearing of the joint. The Balsawood-steel interface is proved to be critical to the mechanical behavior of the joint. Good agreement between experimental results and numerical predictions is observed.  相似文献   

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Optimization procedures are required to minimize the amount of fuel consumption and exhaust emissions from marine engines.This study discusses the procedures to optimize the performance of any marine engine implemented in a 0D/1D numerical model in order to achieve lower values of exhaust emissions. From that point, an extension of previous simulation researches is presented to calculate the amount of SO_x emissions from two marine diesel engines along their load diagrams based on the percentage of sulfur in the marine fuel used. The variations of SO_x emissions are computed in g/k W·h and in parts per million(ppm) as functions of the optimized parameters: brake specific fuel consumption and the amount of air-fuel ratio respectively.Then, a surrogate model-based response surface methodology is used to generate polynomial equations to estimate the amount of SO_x emissions as functions of engine speed and load. These developed non-dimensional equations can be further used directly to assess the value of SO_x emissions for different percentages of sulfur of the selected or similar engines to be used in different marine applications.  相似文献   

16.
高强度船用钢热成形时,由于加热与淬火的交互作用,形成渐变微观结构。研究表明,渐变微观结构使得材料的硬度、强度从里到表依次降低,延展性依次增加,较平缓的冲击力水平及材料的逐层失效使结构保持较高的吸能能力;具有较小的变形抗力、塑性好、成形极限高,而且成形零件的精度和强度较高。渐变微观结构综合了各单相材料的优秀性能,适合用于承受冲击吸能的构件。  相似文献   

17.
To study the applicability of biodiesel in marine engines, this research investigated the performance, combustion characteristics, and emission characteristics of biodiesel(B100), diesel, and a 50% volume blend of the two fuels(B50) in a marine engine. This study was conducted on a 4-cylinder, 520 mm-bore, two-stroke, low-speed marine engine with a common rail fuel and exhaust gas charge system. The three fuels were tested at different loads from 25% – 100% with a step size of 25%. Results showe...  相似文献   

18.
介绍瓦锡兰最新型船用低速电控柴油RT-flex35(W-X35) UNIC系统的控制原理及工作过程,以及与传统的RTA柴油机相比,其主要技术性能指标的优势.概述降低NOx排放的各种措施,以及优化RT-flex35(W-X35)柴油机各项性能指标后,使之更加高效可靠、经济及低排放运行.  相似文献   

19.
The fuel sulfur content in marine fuels has been regulated in Sulfur Emission Control Areas(SECAs) since January 2015. However, other fuel characteristics are also believed to have an impact on particle emissions, particularly on the number of particles emitted. This study investigates the impact of the content of aromatics in fuel. To achieve fuel blends with concentrations of aromatics similar to those found in marine fuel oils, i.e. 20%–30% by volume(%vol.), normal diesel oil(4%–5% vol. aromatics) is doped with a mixture of aromatics. Emission measurements are conducted in test-bed engine facilities and particle emissions over a wide size range are analyzed. Results show a decreased number of particles emitted(or not change) with an increase in the aromatic concentration in fuel. This is because there is a reduction in the cetane number of the fuel with an increased aromatic content, which effects the combustion process and results in decreased particle formation. However, when ignition improver is used to increase the cetane number, particle emissions remain at a lower level than for normal diesel oil; thereby emphasizing the presence of other factors in the formation of particles.  相似文献   

20.
Responses of the very large floating Structures(VLFS) can be mitigated by implementing oscillating water columns(OWCs). This paper explores the fundamental mechanism of present wave interactions with both structures and examines the hydrodynamic performance of VLFS equipped with OWCs(VLFS-OWCs). Under the linear potential flow theory framework, the semi-analytical model of wave interaction with VLFS-OWCs is developed using the eigenfunction matching method. The semi-analytical model is verified ...  相似文献   

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