国际爆破和破碎杂志

1998年第2卷第2期论文摘要 1 断裂力学的创始人——George Rankin Irwin(1907 1998)(H.P.Rossmanith) George Rankin Irwin教授1998年10月9日逝世的不幸消息传出后,他的朋友和断裂力学的同仁们都表示深深的哀悼.Irwin教授为断裂力学奉献了一生,也因此成为断裂力学的创始人,他的名字将永远地记录在断裂力学的发展史中.爆破工程与岩石破碎工程和其它材料的断裂力学问题是紧密相连的,Irwin教授为爆破和破碎技术的发展做出了具有推动性的贡献.为纪念这位伟大的创始人,FRAGBLAST的全体编辑共同撰写了介绍Irwin教授的生平及其大量工程断裂力学著作的文章.本文介绍了断裂力学创始人George RankinIrwin教授的生平业绩,讲述了他在断裂力学的迅速发展过程中所起的重要作用.     

国际爆破和破碎杂志——1998 年第2 卷第2 期论文摘要

１　断裂力学的创始人———ＧｅｏｒｇｅＲａｎｋｉｎＩｒｗｉｎ（１９０７～１９９８）（Ｈ．Ｐ．Ｒｏｓｓｍａｎｉｔｈ）ＧｅｏｒｇｅＲａｎｋｉｎＩｒｗｉｎ教授１９９８年１０月９日逝世的不幸消息传出后，他的朋友和断裂力学的同仁们都表示深深的哀悼。Ｉｒｗｉｎ教授为断裂力学奉献了一生，也因此成为断裂力学的创始人，他的名字将永远地记录在断裂力学的发展史中。爆破工程与岩石破碎工程和其它材料的断裂力学问题是紧密相连的，Ｉｒｗｉｎ教授为爆破和破碎技术的发展做出了具有推动性的贡献。为纪念这位伟大的创始人，ＦＲＡＧＢＬ…     

基于断裂力学的沥青混凝土抗裂性能与研究方法进展

针对断裂力学在沥青混凝土的应用背景以及目前研究的不足，分别从沥青混凝土断裂力学基本理论和沥青断裂性能的研究进展以及沥青混凝土断裂测试方法三个方面总结了相关成果和进展。阐述了线弹性断裂力学、弹塑性断裂力学及疲劳断裂力学在沥青混凝土中的应用条件和评价参数；从材料组成、再生和温拌工艺、路面层间黏结以及细观模拟等方面总结了沥青混凝土抗裂性能的研究现状；列举了目前评价沥青混凝土断裂性能的试验方法；指出了目前研究的不足和以后研究的建议。研究结果表明：沥青混凝土的低温和中温断裂一般分别用线弹性断裂力学和弹塑性断裂力学理论来评价和分析，有必要将线弹性断裂力学和弹塑性断裂力学结合，从而提出一个统一的宽温度域的评价指标；目前针对单调荷载作用下沥青混凝土断裂性能的研究较多，针对循环荷载作用下沥青混凝土断裂行为的研究还较少，有必要通过疲劳试验明确沥青混凝土的裂纹扩展规律；沥青混凝土断裂的细观模拟可以从细观角度揭示裂纹发生和扩展的机理，但破坏模型的选取和细观参数的确定是影响模拟结果准确性的重要因素，需要进一步重视。     

关于按韧性分级选择平台结构钢级问题的探讨

“海上固定平台入级与建造规范”中的钢材等级的选择一览表[1],实质上是以经验为据的,它是为防止平台结构发生快速断裂而作出的规定。 本文按这样的层次分析了该表,即:影响快速一次断裂的诸因素;断裂力学韧性参数可统一概括影响一次断裂的诸因素;采用各钢级已有的断裂力学韧性参数的估算公式,计算了表中各钢级的各临界状态的断裂力学韧性参数。发现各类别构件有各自要求的临界参数级别,故提出了按断裂力学韧性参数分级选择平台结构钢级的观点。基于这一观点,结合我国平台钢的现状,对“一览表”提出了修改和补充建议。     

混凝土断裂力学的发展简介

混凝土断裂力学研究含裂缝体的混凝土材料和混凝土结构的破坏过程以及裂缝传播规律,建立断裂准则,探讨如何控制和防止混凝土结构断裂破坏的措施。本文通过分析混凝土断裂的几个模型,简述混凝土断裂力学的发展过程。     

水库护坡静冰压力及断裂韧度测试研究

该文结合典型水库的实际工程问题,将断裂力学引入进来,从断裂力学的角度分析了该水库护坡产生冰冻破坏的主要原因,针对冰体材料对应变速率反应敏感的特性,在满足条件下,对其进行了符合脆性破坏的断裂力学试验,并分别得到相应的断裂韧度值K_IC和G_C。同时,将其同采用半解析有限元法计算所得到的数值解相比较,两者结果相近、规律相同,进而说明该理论模型及其研究方法是合理有效的。为季节性冻土地区水库护坡抗冰冻破坏问题的研究进行了有意义的尝试,并为其设计提供了参考和依据。     

断裂力学在混凝土结构中的应用

断裂力学是在实践的基础上发展起来研究带裂纹材料或结构的强度以及裂纹扩展规律的一门新兴力学学科。本文通过对断裂力学的论述讲解了其在混凝土的结构中的应用,以及“阻”、“放”、“抗”裂纹控制思想所取得的成果。     

断裂力学在纤维增强复合物破损上应用现状的评述

虽然断裂力学的应用已在通常采用的许多结构材料的破损分析上取得成功,但将它应用于纤维增强复合物却至今尚未奏效。本文将究其基本原因,首次简评在复合物断裂中所包括的细观力学现象,继而对文献中所发表的各种分析方法进行评述。已经发现,这些方法一般是从线弹性断裂力学加以经验外推,是无法对付按细观力学观点所观察到的裂纹扩展的复杂性的。结论是需要革新性的断裂力学技术:提出了一种设想。     

圆钢管混凝土T型焊接节点应力强度因子计算方法研究

主管内填充混凝土的圆管桁架是一种新型结构,鉴于断裂力学评估这种结构疲劳性能的需要,该文探讨了圆钢管混凝土T型焊接节点在支管轴拉力作用下的应力强度因子计算方法.首先,根据节点的热点应力分布和疲劳裂纹试验结果,提出了节点断裂力学分析的半椭圆表面裂纹模型.其次,推导了主管、支管及混凝土等部分的参数变换公式,并通过ANSYS软...     

木材断裂解离分形特征与分形断裂力学模型研究

目的 以椴木为研究对象,研究冲击载荷作用下椴木试件的断裂解离形貌特征和断裂力学特性,建立适用于木材原料断裂解离的分形断裂力学模型,并对其断裂解离力学行为进行描述。方法 对椴木试件进行冲击加载试验,分析试件断口的形貌特征和断裂力学特性,构建适用于木材原料断裂解离的分形断裂力学模型。结果 椴木试件横向冲击断裂断口裂纹形状和断口形貌特征比纵向冲击复杂,横、纵向冲击断裂断口均具有分形特征;椴木试件纵向冲击断裂韧性均值是横向冲击断裂韧性均值的1.112倍,椴木试件横、纵向冲击断口的分形维数均值分别为2.063 5和2.075 1,椴木试件横、纵向冲击韧性与其断口分形维数之间存在线性正相关关系,拟合优度分别为0.778 7和0.812 2;构建的木材原料断裂解离临界解离应力和断裂韧性的分形断裂力学模型也适用于脆性材料。结论 在木材原料冲击断裂解离时,木材原料初始裂纹长度越短,断裂解离断口越粗糙复杂,木材原料断裂解离所需要的能量越大;当裂纹沿着与冲击加载力方向垂直成大约1.055rad方向扩展时所需的能量最小,木材原料最易沿该方向进行断裂解离。     

Effect of Permeable Crystalline Material on Steel Reinforcement Corrosion of Concrete

Permeable crystalline materialcan permeate into pores and cracks of concrete and catalyze the reaction between Ca(OH) 2and unhydrated cement to generate a great quantity needle non-soluble crystals, which can stop up the pores and cracks of concrete, and increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate steel reinforcement corrosion of concrete specimens uncoated and coated with permeable crystalline material as well as mixed with the permeable crystalline material. The properties evaluated for corrosion test were water impermeability, water absorption, compressive strength and potential. The results of water impermeability, water absorption, compressive strength clearly showed that the permeable crystalline material could prohibit water, any soluble salts and moisture from penetrating the concrete to cause corrosion, leaking, and other problems, and it did increase the compressive strength, which was favorable for protection of corrosion of reinforcing steel. Moreover, it was concluded from the potential-time curve that the steel reinforcement of uncoated specimen was in the state of activation whereas that of other specimens coated and mixed with the permeable crystalline material was in the state of inactivation. Above all, it was indicated that the permeable crystalline materialis very effective to protect the steel reinforcement of concrete from corrosion.     

The Research and Application About "Dry Peeling Off" Technology for Airplane Surface Paint Layer

In this paper, the principle of spurting take off lacquer were introduced; and with orthogonal method the unsaturate polyester was prepared ;it was easy to peel airplane paint layer off with this material and equipment.     

Quality Study of Honeycomb Core Shaping Without Wax Stabilization

Sandwich panels utilizing honeycomb cores result in lightweight, high-strength units that are very rigid. Indeed, they give honeycomb panels the best strength-to-weight ratio of any construction type available. Conventionally, the wax is poured into the cell of the core to strengthen the structure and prevent the core from being crushed during milling. Much time and labor is required to wax, mill, and clean the cores. In this study, the process of pouring wax into the core was skipped. In other words, the cutter directly milled the core. Experiments showed that the compressive strength of the core produced without wax stabilization was only 3% lower than that of cores produced using the traditional method. In addition, the drum peel strengths of cores produced without wax stabilization were 38.4% higher than cores produced using the traditional method, in which residual wax seriously polluted the adhesive. It was also found that eliminating the wax process can reduce costs.     

In-process thermal treatment of polylactic acid in fused deposition modelling

Polylactic acid (PLA) is one of the most widely used open source fused filament fabrication materials due to its ease of extrusion, biodegradability, and mechanical strength. The mechanical strength of PLA largely depends on the proper growth of its semi-crystalline structure, which can be severely impaired by a low rate of crystallization, particularly in open source printers. This can be further aggravated by the non-uniform thermal distribution of heat that causes improper curing among the extruded beads of the printing material. As a result, PLA printed on open source printers does not achieve the best mechanical properties. This research, for the first time, proposes an additive-free solution implemented through a detailed set of experimentation to improve the curing rate through in-process temperature variations to cure the joints among the beads. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy is used to confirm the improvements in the bead joints. This work is conducted in two phases of experiments. In the first phase, a full factorial ANOVA is used to investigate various process parameters and the important variables are used in the second phase to print test specimens in four different sets.     

Investigation of the Corrosion Behaviors of HVOF-Sprayed Carbide Cernet Coatings in Molten Al-Zn-Si Alloy Bath

In continuous hot-dip galvanization process the corrosion and chemical stability of the sink roll in the galvanizing bath are important problem which effects on the quality and productivity. In order to protect the sink roll the carbide cermet and/or ceramic coatings were deposited on the surface of the sink roll. The WC-, Cr3 C2-cermet coatings were deposited by high velocity oxygen fuel (HVOF) spray, respectively. The coating samples were immersed in molten Zn-alloy containing 50 wt % aluminum at 833 K for 24 hr and 144 hr, respectively. The inter-diffusion and inter-reaction of Zn, Al and elements in coating and corrosion behaviors of these coatings were investigated by XRD, SEM and EPMA etc. The corrosion mechanisms of the carbide cermet coatings and ceramic coatings in molten High Al-Zn-alloy were approached.     

Fundamental study of adhesion of ice to cooling solid surface (Discussion on influence of copper oxide layer on ice adhesion force)

In many situations, ice often adheres to a cooling solid surface, frequently causing serious accidents. It is critical to clarify the mechanism of ice adhesion to the cooling surface in order to prevent ice adhesion. In a past study, the shearing stresses of two kinds of test plates with a copper surface having the higher thermal conductivity were measured. The shearing stress corresponds to ice adhesion force. Both shearing stresses were significantly different; however, the cause remains unclear.Therefore, the present study focuses on an oxide layer as the main factor causing the difference of both shearing stresses; the influence of the oxide layer formed on shearing stress was discussed. And in the removal and reformation processes of the oxide layer, the time variation of the shearing stress was clarified. Moreover, the relationship between the state of the copper surface and the shearing stress was also clarified by surface analysis.     

＂Three Transformations＂ and Standardization

During his inspection in Henan Province in May, Chinese President Xi Jinping stressed to ＂push forward the transformation from China Speed to China Quality, from Made in China to Created in China, and from Chinese Products to Chinese Brand＂. The ＂Three Transformations＂ are the specific requirements and goal of China＇s national development in the context that market should play a decisive role in the allocation of resources.     

重塑标准推行格局 推动LED照明的普及（英文）

正When you are enjoying the green,energy-saving and healthy lighting of IKEA LED luminaire,you may not realize that most of IKEA’s LED bulbs are produced by the LED luminaire smart manufacturing system of Hangzhou Zhongwei Photoelectricity CO.,LTD(ZVISION).No longer enclosed in the laboratory,the product standards are brought into the factory workshop and even to the entire production process.Thus,the standards are promoted and applied in a favorable way by enterprises,benefitting consumers with high quality products.     

Chinese Experts Contribute to ISO＇s New Toy Standards

正The international standard,ISO 8124-6,Safety of toys–Part 6:Certain phthalate esters in toys and children’s products,was officially issued by ISO worldwide on August 15.It was the first time for Chinese experts to lead the ISO standard development in toys industry.The standard was drafted by a group of Chinese experts from SAC/TC for toys and relevant Chinese departments and finally completed by a dedicated international group of experts.ISO 8124-6 makes a substantive breakthrough in the aspects of the scope of toys,limitation of plasticizer types,control of test cost,accuracy of test,operation convenience,etc.,offering the operational guidance for toy manufactures and testing laboratories.     

SAC Delegation Visits AENOR and Signs Cooperation Agreements

正SAC Administrator Tian Shihong led the Chinese delegation to visit the Spanish Association for Standardization and Certification(AENOR)on September 15,2014.Mrs.Begona Cristeto,the Vice-Minister of Industry,Energy and Tourism of Spain,and Mr.Avelino Brito,the President and CEO of AENOR greeted the delegation.The two sides had a deep and friendly discussion on strengthening the cooperation between China and Spain in the standardization field and promoting the standardization work to support the development of economy and trade in the two countries.