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The Effect of Welding Parameters on the Corrosion Resistance of Austenitic Stainless Steel 焊接参数对奥氏体不锈钢耐蚀性的影响
IF 1.3 Q3 ENGINEERING, MECHANICAL Pub Date : 2022-02-23 DOI: 10.3311/ppme.19568
D. Kemény, D. Kovács
Electricity produced in power plants is essential in our everyday life. In general, the energy transfer takes place after processing the energy source in boilers or steam generators. Steam is generated through this process, that operates the turbines and they generate electricity through the generators. As such equipment operates in a high pressure, corrosive and high temperature environment, these circumstances may damage the tubes in the heat exchangers. Our research examines the potential of corrosion of heat exchanger tubes after welding. The typical corrosion process is pitting. The corrosion resistance of stainless steel depends on a protective, passive film formed on the surface of the steel exposed to the service environment. The use of fusion welding for fabrication leads to local variations in the chemical composition inside the material, which may significantly alter the stability of the passive layer and hence the corrosion behavior. The impact of welding parameters (shielding gas, amperage) was examined on corrosion resistance of X6CrNiTi18-10 austenitic stainless steel. The corrosion test was performed according to ASTM G48 standard. The weight loss was measured in Fe(III)-chloride solution by the first corrosion test. The results showed that the corrosion resistance of stainless steel was better at 50 A and 10 l/min welding parameters. During the second test, a potentiodynamic corrosion test was made, and the potentiodynamic curve was measured in 9% saline solution. In this solution, the stainless steel had a better corrosion property because it was measured in a less aggressive medium.
发电厂产生的电对我们的日常生活是必不可少的。一般来说,能量传递是在锅炉或蒸汽发生器对能量源进行处理后进行的。蒸汽是通过这个过程产生的,它带动涡轮机,涡轮机通过发电机发电。由于此类设备工作在高压、腐蚀性和高温环境中,这些情况可能会损坏换热器内的管。我们的研究考察了热交换器管焊接后腐蚀的可能性。典型的腐蚀过程是点蚀。不锈钢的耐腐蚀性取决于暴露在使用环境中的钢表面形成的保护性钝化膜。使用熔焊制造会导致材料内部化学成分的局部变化,这可能会显著改变被动层的稳定性,从而改变腐蚀行为。研究了焊接参数(保护气体、电流)对X6CrNiTi18-10奥氏体不锈钢耐蚀性的影响。腐蚀试验按ASTM G48标准进行。通过第一次腐蚀试验,测定了铁(III)-氯化物溶液中的失重量。结果表明,在50a和10l /min的焊接参数下,不锈钢的耐腐蚀性能较好。第二次试验进行动电位腐蚀试验,在9%的盐水溶液中测定动电位曲线。在这种溶液中,不锈钢具有更好的腐蚀性能,因为它是在腐蚀性较小的介质中测量的。
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引用次数: 3
Comparison of Multi-Criteria Decision Making Methods for Multi Optimization of GTAC Process Parameters GTAC工艺参数多准则优化决策方法的比较
IF 1.3 Q3 ENGINEERING, MECHANICAL Pub Date : 2022-02-18 DOI: 10.3311/ppme.19835
R. Ranjan, A. Saha, Anil Kumar Das Kumar Das
A great deal of investigation on gas tungsten arc cladding (GTAC) is focused on the study of enhancements in the microstructure, mechanical and tribological features of the cladding. The selection of right process parameters is a critical issue for the researchers. Decision makers in the industries must analyze a wide variety of parameters based on a set of contradictory criteria. Several multi-criteria decision-making (MCDM) techniques are now available to add values in selection of these parameters. The application of the TOPSIS and MOORA techniques to identify the best configuration of processing parameters in the gas tungsten arc cladding (GTAC) process is investigated in this work. The best processing parameters set for the multiple performance attributes should be welding current: 70 amp, speed: 240, argon flow: 13 and standoff distance 3.5 (TOPSIS-PCA) and welding current: 50, speed: 300, argon flow: 13 and standoff distance 3.5 (MOORA-PCA).A comparison of MOORA-PCA and TOPSIS-PCA demonstrates the superiority of TOPSIS over MOORA technique. The prediction accuracy of the TOPSIS-PCA hybrid approach model is found better than MOORA-PCA technique.
对气体钨弧熔覆层(GTAC)的研究主要集中在提高熔覆层的微观结构、力学性能和摩擦学性能方面。选择合适的工艺参数是研究人员面临的一个关键问题。行业中的决策者必须根据一组相互矛盾的标准分析各种各样的参数。现在有几种多标准决策(MCDM)技术可用于在这些参数的选择中增加值。本文研究了利用TOPSIS和MOORA技术确定气体钨弧包覆(GTAC)工艺参数的最佳配置。多个性能属性的最佳工艺参数设置为:焊接电流70安培、速度240、氩气流量13、距离3.5 (TOPSIS-PCA);焊接电流50、速度300、氩气流量13、距离3.5 (MOORA-PCA)。通过对MOORA- pca和TOPSIS- pca的比较,证明了TOPSIS技术优于MOORA技术。TOPSIS-PCA混合方法模型的预测精度优于MOORA-PCA技术。
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引用次数: 0
The Effect of the Field of Adaptation on Chromatic Discrimination Ellipses 自适应场对色差判别椭圆的影响
IF 1.3 Q3 ENGINEERING, MECHANICAL Pub Date : 2022-02-17 DOI: 10.3311/ppme.19552
Á. Urbin, B. Nagy, K. Wenzel
In this paper results of chromatic discrimination measurements obtained in two lighting scenarios are compared. Chromatic discrimination thresholds were measured in relation with systematically manipulated chromaticities seen under different visual angles. In both cases the Ellipse module of the Cambridge Colour Test (CCT) was obtained binocularly by normal colour-observers. Discrimination ellipses fitted to the measured thresholds were compared in terms of the adapting chromaticity and the visual angle of the adapting stimulus. Our findings show that changes in the reference chromaticity of the CCT have stronger effect on the elongation of the chromatic discrimination ellipses compared to the effect of the adapting chromaticity obtained in a light booth.Further comparison of discrimination thresholds estimated towards the confusion directions and the corresponding radii of the Ellipse test results suggests that the reliability of the Ellipse test results depends on the relation between the measurement directions and the confusion directions.
本文对两种光照条件下的色差测量结果进行了比较。色差阈值测量与系统操纵色度在不同视角下看到的关系。在这两种情况下,剑桥颜色测试(CCT)的椭圆模块是由正常的颜色观察者双眼获得的。在适应色度和适应刺激的视角方面,比较了符合测量阈值的识别椭圆。我们的研究结果表明,相比于在灯箱中获得的自适应色度的影响,CCT参考色度的变化对色差椭圆的延伸有更强的影响。进一步将混淆方向的判别阈值与椭圆检验结果的相应半径进行比较,表明椭圆检验结果的信度取决于测量方向与混淆方向之间的关系。
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引用次数: 0
Monitoring and Regulation of Indoor Conditions 监测和调节室内条件
IF 1.3 Q3 ENGINEERING, MECHANICAL Pub Date : 2022-02-03 DOI: 10.3311/ppme.19443
M. Stojkov, Krešimir Crnogorac, Tomislav Alinjak, Bernarda Crnogorac
This paper presents research of energy performance analysis performed by Building Energy Management System (BEMS). BEMS is a system/platform integrated with building and it is an enormous improvement in a process to develop nearly zero energy buildings (nZEB). Near zero energy consumption stands for energy efficient idea of energy independent buildings for their function during their life time. Here, BEMS with function of monitoring and regulation of cooling energy demand is developed. BEMS regulates function of ventilation fan in area below tin roof and improves working conditions by inside building temperature reduction during summer period. Described technical solution is designed inside RESCUE IPA CBC project.
本文对建筑能源管理系统(BEMS)的能源绩效分析进行了研究。BEMS是一个与建筑集成的系统/平台,它是开发近零能耗建筑(nZEB)过程中的巨大改进。接近零能耗代表了能源独立建筑在其生命周期内的节能理念。在此基础上,开发了具有制冷能源需求监测和调节功能的BEMS系统。BEMS调节锡屋顶以下区域通风机功能,通过夏季建筑内部降温改善工作条件。描述了救援IPA CBC项目的技术方案设计。
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引用次数: 1
Multi-Parameter Layup Optimization and the Effect of Layup Homogenization on the Bending Compliance Matrix of Coupled Composites 多参数铺层优化及铺层均匀化对耦合复合材料弯曲柔度矩阵的影响
IF 1.3 Q3 ENGINEERING, MECHANICAL Pub Date : 2022-02-02 DOI: 10.3311/ppme.19702
T. Czigány, Brúnó Vermes
The behaviour of fibre-reinforced composites greatly depends on their layup structures. Through a full-field layup optimization study based on multiple parameters, this paper investigates how different properties change with the layup. The aim was to maximize the extension-twist coupling performance while ensuring adequate bending stiffness and low thermal warpage to make the laminate suitable for shape-adaptive helicopter rotor blade application. The Classical Laminate Theory-based calculations revealed that satisfying the bending compliance and thermal warpage criteria significantly limited the achievable extension-twist performance. The warpage limit affected the desired coupling behaviour more because both properties are driven by terms in the extensional-bending compliance matrix, unlike bending compliance. Symmetric laminates do not have an intrinsic extension-twist capability, but some asymmetric laminates demonstrated significant coupling performance while being practically warpage-free (based on the ISO2768 standard). The results prove that the advantages of asymmetric laminates can outweigh their sometimes negligible disadvantages. The paper also investigates if there is a universal tendency in how layup homogenization affects the terms of the bending compliance matrix of composites. Through analytical calculations, we showed that depending on the layup of the sub-laminate, homogenization can increase or reduce the value of any term in the bending compliance matrix; therefore, there is no universal tendency. Based on these results, layup homogenization cannot only be exploited for its most general purpose – warpage mitigation – but also for improving other characteristics of the laminate (e.g. reducing the bending compliance for increased bending stiffness or increasing the bend-twist compliance for improved coupling performance).
纤维增强复合材料的性能在很大程度上取决于其层状结构。通过多参数的全油田铺层优化研究,探讨了不同性质随铺层的变化规律。其目的是最大限度地提高拉伸-扭转耦合性能,同时确保足够的弯曲刚度和低热翘曲,使层压板适合形状自适应直升机旋翼叶片的应用。基于经典层压板理论的计算表明,满足弯曲顺应性和热翘曲准则严重限制了可实现的伸扭性能。翘曲极限对期望的耦合行为影响更大,因为这两种特性都是由伸展弯曲柔度矩阵中的项驱动的,而不像弯曲柔度。对称层压板不具有固有的拉伸扭转能力,但一些非对称层压板在几乎无翘曲的情况下表现出显著的耦合性能(基于ISO2768标准)。结果证明,不对称层压板的优点可以超过它们有时可以忽略不计的缺点。本文还研究了叠层均匀化对复合材料弯曲柔度矩阵项的影响是否存在普遍趋势。通过分析计算,我们发现,根据分层层的不同,均匀化可以增加或减少弯曲柔度矩阵中任何一项的值;因此,没有普遍的趋势。基于这些结果,铺层均匀化不仅可以用于其最一般的目的-翘曲缓解-而且还可以用于改善层压板的其他特性(例如,减少弯曲顺应性以增加弯曲刚度或增加弯曲扭曲顺应性以改善耦合性能)。
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引用次数: 0
Agitation of Complex Fluids in Cylindrical Vessels by Newly Designed Anchor Impellers 新设计的锚定叶轮对圆柱形容器内复杂流体的搅拌
IF 1.3 Q3 ENGINEERING, MECHANICAL Pub Date : 2022-01-13 DOI: 10.3311/ppme.18438
Benhanifia Kada, Rahmani Lakhdar, Mebarki Brahim, H. Ameur
The fluid flows and power consumption in a vessel stirred by anchor impellers are investigated in this paper. The case of rheologically complex fluids modeled by the Bingham-Papanastasiou model is considered. New modifications in the design of the classical anchor impeller are introduced. A horizontal blade is added to the standard geometry of the anchor, and the effect of its inclination angle (α) is explored. Four geometrical configurations are realized, namely: α = 0°, 20°, 40°, and 60°. The effects of the number of added horizontal blades, Reynolds number, and Bingham number are also examined. The obtained findings reveal that the most efficient impeller design is that with (case 4) arm blades inclined by 60°.This case allowed the most expansive cavern size with enhanced shearing in the whole vessel volume. The effect of adding second horizontal arm blades (with 60°) gave better hydrodynamic performance only with a slight increase in power consumption. A significant impact of Bingham number (Bn) was observed, where Bn = 5 allowed obtaining the lowest power input and most expansive well-stirred region.
本文研究了锚桨搅拌船舶内的流体流动和动力消耗。考虑了用Bingham-Papanastasiou模型模拟的流变复杂流体的情况。介绍了经典锚杆叶轮在设计上的新改进。在锚的标准几何形状中加入水平叶片,探讨了其倾角(α)对锚的影响。实现了四种几何构型,即:α = 0°、20°、40°和60°。研究了添加水平叶片数、雷诺数和宾汉姆数的影响。所得结果表明,最有效的叶轮设计是(例4)臂叶倾斜60°。在这种情况下,整个容器体积的剪切能力增强,洞室尺寸最大。增加第二个水平臂叶片(60°)的效果使水动力性能更好,但功率消耗略有增加。宾汉姆数(Bn)的显著影响被观察到,其中Bn = 5允许获得最低的功率输入和最广阔的均匀搅拌区域。
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引用次数: 5
Study of the Stress State of a Dissimilar Metal Weld Due to Manufacturing and Operational Conditions 制造和操作条件下异种金属焊缝应力状态的研究
IF 1.3 Q3 ENGINEERING, MECHANICAL Pub Date : 2022-01-07 DOI: 10.3311/ppme.19063
Bernadett Spisák, Z. Bézi, S. Szávai
Welding is accompanied by the presence of weld residual stresses, which in case of dissimilar metal welds even with post weld heat treatment cannot be removed completely therefore they should be considered when assessing possible welding defects. The measurement of residual stress in metal weld is a very complex procedure and also in the investigated case could not be carried out as it is the part of a working plant. However, by modelling these processes, the residual stresses and deformation of the components caused by this manufacturing method can be determined. It is important to calculate these values as accurately as possible to determine the maximum load capacity of the structure. The structure under examination was the dissimilar metal weld of a VVER-440 steam generator. 2D simulations were performed, where temperature and phase-dependent material properties were implemented. Different loading scenarios were considered in the numerical analysis. The results can be useful to determine the real loading conditions of a given component and can be used to predict stress corrosion crack initiation locations, as well as to evaluate the lifetime and failure mode prediction of welded joints.
焊接伴随着焊缝残余应力的存在,在不同金属焊缝的情况下,即使焊后热处理也不能完全消除残余应力,因此在评估可能的焊接缺陷时应考虑残余应力。金属焊缝残余应力的测量是一个非常复杂的过程,而且在本研究案例中,由于它是工作设备的一部分,因此无法进行测量。然而,通过对这些过程进行建模,可以确定由这种制造方法引起的部件的残余应力和变形。重要的是要尽可能准确地计算这些值,以确定结构的最大承载能力。所研究的结构是VVER-440蒸汽发生器的异种金属焊缝。进行了2D模拟,其中实现了与温度和相相关的材料特性。数值分析中考虑了不同的加载情况。该结果可用于确定给定构件的实际加载状态,并可用于预测应力腐蚀裂纹起裂位置,以及评估焊接接头的寿命和失效模式预测。
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引用次数: 2
The Effect of Genders on the Perception of the Combined Effect of Local Discomfort Parameters 性别对局部不适参数综合效应感知的影响
IF 1.3 Q3 ENGINEERING, MECHANICAL Pub Date : 2021-12-22 DOI: 10.3311/ppme.18249
Balázs András-Tövissi, L. Kajtár
If the draught and the radiant thermal asymmetry caused by the warm ceiling appear simultaneously, will women and men be affected in the same way? This research aims to answer this question, by clarifying the understanding of the joint mechanism of action of the two local discomfort factors with the help of instrumental and human subject measurements. The most important result of the present research is identifying that if PPD < 6%, radiant thermal asymmetry varies in the range of 5–15 °C and the draught rate DR = 15% or DR = 25%, then at a given range of the interval men are significantly more dissatisfied with warm ceilings than women; women’s AMV votes are significantly lower than men's; In the case of DR = 15%, the work accuracy of women is significantly higher, while in the case of men, the work accuracy is higher at DR = 25%.
如果温暖的天花板造成的通风和辐射热不对称同时出现,女性和男性会受到同样的影响吗?本研究旨在回答这一问题,通过仪器测量和人体受试者测量来阐明两种局部不适因素的共同作用机制。本研究最重要的结果是,如果PPD < 6%,辐射热不对称性在5-15°C范围内变化,通风率DR = 15%或DR = 25%,那么在给定的区间内,男性对温暖天花板的不满程度明显高于女性;女性的AMV投票明显低于男性;在DR = 15%的情况下,女性的工作准确率明显更高,而在男性的情况下,DR = 25%的工作准确率更高。
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引用次数: 0
Vibrations in Single-Degrees-of-Freedom Sampled-Data Linear Mechanical Systems 单自由度采样数据线性机械系统的振动
IF 1.3 Q3 ENGINEERING, MECHANICAL Pub Date : 2021-12-15 DOI: 10.3311/ppme.19150
Csaba Budai
This paper aims to present that the effect of sampling can result in multi-frequency vibration even in the case of a single-degree-of-freedom linear mechanical model. Even though the sampled-data systems have an infinite number of characteristic exponents due to sampling, the vibrations of these systems can still be characterized by an effective system model with a single dominant frequency. However, as this paper shows, additional harmonics become relevant, resulting in multi-frequency vibrations depending on the magnitude of applied control parameters. The vibrations presented by the time histories of vibration and their spectra resulted in numerical simulation of the sampled-data system.
本文旨在说明即使在单自由度线性力学模型中,采样的影响也会导致多频振动。即使采样数据系统由于采样而具有无限数量的特征指数,这些系统的振动仍然可以用具有单一主频率的有效系统模型来表征。然而,正如本文所示,额外的谐波变得相关,导致多频振动取决于应用控制参数的大小。由振动时程及其谱所表示的振动,对采样数据系统进行了数值模拟。
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引用次数: 1
Prediction of the Shear Tension Strength of Resistance Spot Welded Thin Steel Sheets from High- to Ultrahigh Strength Range 高强度到超高强度范围内电阻点焊薄钢板剪切抗拉强度的预测
IF 1.3 Q3 ENGINEERING, MECHANICAL Pub Date : 2021-12-15 DOI: 10.3311/ppme.18934
K. Májlinger, L. Katula, B. Varbai
The tensile strength of newly developed ultra-high strength steel grades is now above 1800 MPa, and even new steel grades are currently in development. One typical welding process to join thin steels sheets is resistance spot welding (RSW). Some standardized and not standardized formulas predict the minimal shear tension strength (STS) of RSWed joints, but those formulas are less and less accurate with the higher base materials strength. Therefore, in our current research, we investigated a significant amount of STS data of the professional literature and our own experiments and recommended a new formula to predict the STS of RSWed high strength steel joints. The proposed correlation gives a better prediction than the other formulas, not only in the ultra-high strength steel range but also in the lower steel strength domain.
目前新开发的超高强度钢种的抗拉强度已达到1800mpa以上,甚至目前还在开发新的钢种。薄钢板连接的典型焊接工艺是电阻点焊(RSW)。一些标准化和非标准化的计算公式预测了焊接接头的最小抗剪强度,但随着母材强度的提高,这些计算公式的准确性越来越低。因此,在我们目前的研究中,我们研究了大量的专业文献的STS数据和我们自己的实验,并推荐了一个新的公式来预测RSWed高强度钢节点的STS。所提出的关联关系不仅在超高强度钢的范围内,而且在低强度钢的范围内,都比其他公式具有更好的预测效果。
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引用次数: 5
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