数字化智能化产品设计方法与技术的发展

目的 回顾产品设计方法与技术的发展经历,建立设计方法与技术的定式化分类框架,分析数字化智能化产品设计技术的研究与应用热点,展望智能化创新设计技术的未来发展趋势与挑战。方法 通过对已有的产品设计方法与技术的分析,将设计对象、设计阶段、设计资源、设计手段作为设计方法与技术的分类要素,构建设计方法与技术的定式化分类框架;通过确定各分类要素的具体内容,可以明确不同的设计方法与技术,如数字化智能化产品设计技术;利用该定式化分类框架,展望未来数字化智能化产品设计技术的发展趋势。结论 提出了一种用于产品设计方法与技术定式化的分类框架,界定了基于模型的系统设计与仿真优化、基于互联网的开放式众包设计和数据驱动的设计等三个热点研究方向,指出了产品全生命周期一体化设计、混合智能驱动的创新设计的趋势与挑战。     

地质录井中自动对比技术研究应用

自动对比技术是一种较为精确的录井技术,不仅要强化对于自动对比录井技术的理论研究,要注意在实际录井工作中不断总结经验。本文分析了自动对比录井技术中选取对比曲线以及确定标准层与标志层的方法,同时探讨了自动对比录井技术在现场地层勘探中的应用方法,包括地质录井当中的自动对比原则以及对比方法,处理对比曲线滤波的方法以及自动对比录井技术的实现方法。     

浅议定额制定的基本方法

<正>定额制定的基本方法主要包含有:技术测定法、统计分析法、数理统计法、类推比较法和经验估计法等方法。一、技术测定法技术测定法是一种建立在深入调查研究基础上的技术定额测定方法.要求对施工过程的技术条件、组织条件和施工方法进行分析研究,采取措施,充分挖掘生产潜力的基础上,应用计时观察的方法和材料消     

固体矿产区域找矿技术方法研究分析

固体矿产是我国重要的矿产资源，在总结分析目前固体找矿技术的现状之后，结合世界先进的找矿技术，分析目前主要的找矿方法，从基本的固体矿产区域的找矿思路着手，具体分析找矿的技术方法和未来找矿技术方法的主要发展方向。     

汽车故障的新型无线诊断技术应用探讨

该文针对传统汽车诊断技术方法存在的问题,探讨了现代新型汽车故障诊断技术方法。研究分析了新型汽车故障诊断技术方法的原理及实施现状,新型汽车故障无线检测诊断技术虽存在技术欠成熟等问题,但具备应用简单便捷、易掌握推广等显著特点,突出了其优势,易受普通车主及专业技术人员的偏爱。因此汽车故障无线检测诊断技术具有良好的实用性及推广价值。     

电子电路EDA技术及应用

简要介绍EDA技术的基本特点,论述EDA技术及其发展.基于V叻L的自顶向下的设计方法,比较EDA技术与传统电子设计方法的差异,给出电子设计领域的全新理念.     

CCD和DLP技术光学系统分辨率的现代测试技术研究

提出了一种采用DLP光电图形自动生成技术、CCD摄像技术及计算机图像处理技术等现代技术对光学系统的分辨率进行测试的新方法.该方法可实现客观数字化测量.因此可消除目视检查方法的易疲劳、人为影响等现代技术因素大等诸多缺陷,使得检测准确度高、自动化程度高.     

草莓贮存保鲜技术的研究进展

目的保鲜技术一直是延长草莓货架寿命、提高贮存时间的有效方法,总结当前先进保鲜方法,为研究学者提供研究方向和技术改进措施。方法文中主要在分析草莓如何快速腐烂变质原因的基础上,阐述目前国内外学者对于草莓贮存保鲜的先进技术方法和进展,介绍了气调、热处理、可食涂膜、瓦楞纸箱涂膜、辐照等保鲜技术的原理、特点、实现过程以及技术效果,对草莓保鲜技术的未来发展方向做出了展望。结论目前保鲜技术可将草莓的货架寿命延长至20 d以上,研究成果推动了草莓种植业的发展,提高了草莓的经济价值,并提升了我国对于草莓保鲜技术的研究水平。     

定向碳纳米管的制备及其场发射性能研究

定向碳纳米管的制备方法是碳纳米管场发射显示器技术领域一项十分关键的技术.简要介绍了定向碳纳米管的制备方法、结构检测技术,并综合评述了影响定向碳纳米管场发射性能的因素.     

全息技术在检测技术中的应用

为了解决复杂结构的检测问题,采用以激光技术为基础的全息技术.通过分析全息技术的理论基础、基本过程和实现方法以及全息图的基本特点,讨论全息技术在检测领域中的应用原理、实现方法,特别是在全息金属无损检测和全息振动测试两个方向上,较详细地研究了这两种检测技术的应用原理、实现方法及适用场合,为全息技术在检测领域中实践应用提供一个有价值的理论参考.     

人工神经网络法在镍基变形合金蠕变断裂寿命预测中的应用

在试验数据的基础上,利用人工神经网络建立不同成分镍基变形合金的不同温度,外应力与蠕变断裂寿命之间关系模型,并进行网络训练,对合金的蠕变断裂寿命进行模拟.结果表明,模拟结果与实测结果吻合良好,采用人工神经网络方法可以为镍基变形合金蠕变断裂寿命的预测提供一种有效的手段.     

Creep deformation and rupture behaviour of directionally solidified GTD 111 superalloy

The creep behaviour of directionally solidified (DS) Ni‐base superalloy GTD 111 has been investigated at various temperatures (649 °C to 982 °C) and stresses (124 MPa to 896 MPa). Specimens machined in longitudinal and transverse directions with respect to the grain orientation from three batches of the material were tested. The specimens in the longitudinal direction consistently exhibited higher creep rupture life and creep ductility than specimens from the transverse direction. There were some systematic variations in creep deformation and rupture behaviour among specimens from different batches. Optical and scanning electron microscopy investigations were conducted to understand the creep rupture behaviour. Various deformation and rupture models were evaluated for representing the creep behaviour of the alloy and a neural network model was applied to creep rupture data to assess its predictive capability.     

Neural networks for critical high temperature component life prediction

Abstract

The aim of the present research was to subject a well known parametric model and a neural network model to an acid test of extrapolation in order to determine which can produce improved long term creep rupture life predictions for 2·25Cr–1Mo steels. Linear, squared and cubic parametric models were used and the accuracy of the predictions assessed by calculating the mean percentage absolute error. Many different neural network geometries were developed and the accuracy of the predictions was assessed again by calculating the mean percentage absolute error. As the predictions are concerned with the long term rupture life of components, the accuracy below 60 MPa is of the greatest importance. A neural network model with a 2–5–5–1 architecture provided the lowest error for predictions below 60 MPa, compared to other neural networks and the parametric models, and is therefore the optimum model from this study for predictions of long term rupture creep life for a 2·25Cr–1Mo steel.     

Prevention of the overestimation of long-term creep rupture life by multiregion analysis in strength enhanced high Cr ferritic steels

Long-term creep rupture life is often evaluated from short-term data by a time–temperature parameter (TTP) method. However the conventional TTP methods sometimes fail in understanding creep rupture behavior of strength enhanced high Cr ferritic steels and overestimate creep rupture life in long-term creep. In the present paper, creep rupture data of seven kinds of heat resistant steels with different W and Cr concentrations have been analyzed. The conventional TTP method like Orr–Sherby–Dorn analysis evaluates long-term creep rupture life assuming a unique value of activation energy for all the creep rupture data. This analysis is called single region analysis in this paper. The single region analysis can represent well the creep rupture data of steels containing less than 8% Cr. The creep rupture analyses of steels containing more than 8% Cr exhibit that apparent activation energy changes from a high value in short-term creep region to a low value in long-term creep region. In each case a creep data was divided into several data sets, and then the conventional single region analysis was applied to each divided data set. This analysis is referred to as multiregion analysis. The multiregion analysis describes very well all the data points, whereas regression curves of the single region analysis deviate from the data points, resulting in overestimation of long-term rupture life. The difference between the two activation energies of short-term and long-term creep increases with increasing Cr concentration. Therefore, the overestimation due to singles region analysis is expected to be more serious at higher Cr concentration.     

Creep properties of a U‐type notch plate in Ni‐based superalloy

In the present investigation, the effect of notch on creep rupture behavior and creep rupture life of a Ni‐based superalloy has been assessed by performing creep tests on smooth and U‐notched plate specimen under 0°C. The finite element analysis coupled with continuum damage mechanics are carried out to understand the stress distribution across the notch throat and the creep damage evolution under multi‐axial stress state. The creep rupture life of U‐notched specimen is much larger than that of plane plate specimen under the same stress condition, indicating that there is a strengthening effect on notch specimen. Creep rupture life increases with increasing the notch radius, the smaller notch radius can induce the creep rupture easier. The effect of notch on the creep damage is also studied. It is found that the location of the maximum creep damage and the maximum equivalent creep strain initiates first at the notch root and gradually moves to the inside as the notch radius increases.     

基于应力松弛实验对服役25Cr35Ni型耐热钢的高温性能评估

以服役的25Cr35Ni型钢为对象,研究利用应力松弛实验开展高温性能评估的方法以及对持久性能的预测效果。结果表明:由于高温服役后晶界处碳化物出现网链状和奥氏体基体内二次碳化物明显粗化,25Cr35Ni型耐热钢持久性能降低。通过得到的不同温度和应力的松弛蠕变速率曲线及外推关系,结合松弛蠕变速率-断裂时间关系方程,可以实现由松弛实验及少量蠕变持久实验开展持久寿命评估。与基于高温持久实验的预测结果比较,两者吻合较好。     

Effects of creep ductility and notch constraint on creep fracture behavior in notched bar specimens

The creep rupture life of U-type notched specimens and smooth specimens has been calculated based on the ductility exhaustion damage model using stress-dependent creep ductility. Effects of creep ductility and notch constraint on creep fracture behaviour in notched bar specimens have been investigated. The results show that the U-type notch exhibits notch strengthening effect under a wide range of stress level and notch constraint condition (notch acuity) for creep ductile materials. The lower equivalent stress in notched specimens plays main role for reducing creep damage and increasing rupture life. The rupture life of notched specimens of creep brittle materials (with lower creep ductility) decreases with the increase in stress level and notch constraint. With increasing creep ductility and decreasing notch constraint, the degree of the notch strengthening effect increases. In creep life designs and assessments of high-temperature components containing notches, the material creep ductility, notch constraint and stress levels need to be fully considered.     

Low cycle fatigue and creep–fatigue interaction behavior of 316L(N) stainless steel and life prediction by artificial neural network approach

Low cycle fatigue (LCF) behavior of solutionized 316L(N) stainless steel (SS) has been studied at various temperatures, strain amplitudes, strain rates, hold times and in 20% prior cold worked condition. The alloy in general showed a reduction in fatigue life with, increase in temperature, increase in strain amplitude, decrease in strain rate, an increase in duration of hold time in tension and with prior cold work. The LCF and creep–fatigue interaction (CFI) behavior of the alloy was explained on the basis of several operative mechanisms such as dynamic strain ageing, creep, oxidation and substructural recovery. The capability of artificial neural network (ANN) approach to life prediction under LCF and CFI conditions has been assessed by using the data generated in the present investigation. It is demonstrated that the prediction is within a factor of 2.     

电站锅炉承压元件的寿命评估方法

综述了国内外迄今为止提出的关于电站锅炉承压元件在运行工况下寿命评估的主要方法.这些方法主要分为以传统持久强度试验外推为主的方法和以蠕变变形和裂纹扩展为主的方法,前者包括持久强度曲线外推法、时间-温度参数法和Robinson寿命消耗法则等;后者包括θ法、C射影法、蠕变曲线逐步外推法以及蠕变损伤开裂及裂纹扩展的评估方法等.     

Creep property of composite solders reinforced by nano-sized particles

In the present work the creep properties of Sn37Pb and Sn0.7Cu based composite solders with nano-sized metallic Cu, Ag and nano-sized oxide Al₂O₃, TiO₂ reinforcement particles have been studied. First, a series of volume percentages of reinforcements were selected for optimizing the content of particles. Then, the composite solder with optimum volume fraction of the reinforcement particles, corresponding to maximum creep rupture life, is selected for investigating the effect of applied stress level and test temperature on creep rupture life of the composite solder joints. In the creep rupture life test, small single-lap tensile-shear joints were adopted. The results indicate that all the composite solders have improved creep resistance, comparing to the eutectic Sn37Pb solder and the Sn0.7Cu lead-free solder. The creep rupture life of the composite solder joints is first increased with the increase in the volume fraction of reinforcement in the composite solders. Then, the creep rupture life is decreased, as the reinforcement content exceeds a certain value. The creep rupture life of the solder joints is decreased with the increase of applied stress and testing temperature. Moreover, the reinforced efficiency of nano-sized Ag particles is the best in all the tested nano-sized reinforcements for the Sn37Pb based and Sn0.7Cu based composite solders, when the particles contents are in their own optimum content.