超细晶WC-Co硬质合金抗拉强度有限元计算方法研究

基于超细晶WC-Co硬质合金真实金相图片,开展有限元模拟拉伸断裂试验,模拟了硬质合金拉伸断裂的具体过程,并利用LS-DYNA有限元方法预测了超细晶WC-Co硬质合金的抗拉强度。根据数值模拟结果,WC-Co硬质合金抗拉强度为132 MPa。将超细晶WC-Co硬质合金加工成中间钻孔的圆盘,通过改进的巴西劈裂试验,间接测量出超细晶WC-Co硬质合金的最大抗拉强度为114.5 MPa。将数值模拟结果与试验结果进行比较,误差约为15%。数值模拟结果与试验结果比较接近,说明基于超细晶真实金相图片的有限元裂纹扩展模拟能较为准确地再现硬质合金断裂失效的过程,预测材料的力学性能,为分析硬质合金的断裂失效提供依据。

三维建模在线路施工图设计中的应用

在输电线路工程的施工图设计中,提出了一种基于SLW软件接口的施工图三维地物建模技术路线,给出了道亨SLW文件的平面地物建模、输电设备解析的方法,并基于此开发了线路三维平台,最后结合滇西北至广东±800kV工程进行了实践应用。

特高强钢芯铝合金绞线在大跨越输电线路中应用

导线选型是大跨越输电线路的关键技术之一,对工程造价和安全运行意义重大。针对特高强钢芯铝合金绞线进行了载流能力分析,对导电材质不一样的JLHA1与NRLH2型两种特高强钢芯铝合金绞线进行了对比分析,从输送能力、铝部应力、经济性等方面系统地分析了特高强钢芯铝合金绞线导电层、承力层材质、铝钢比、钢芯强度对大跨越导线选型设计的影响,并给出大跨越输电线路导线设计建议。

同走廊单避雷线的研究应用

以EGM计算模型为基础,通过考虑同走廊线路避雷线的相互屏蔽作用,修正线路绕击跳闸率,并据此提出同走廊下采用单避雷线的方案。通过分析平行间距对同走廊屏蔽效果的影响,提出保证屏蔽效果下最大平行间距。根据导线参数及最大弧垂,计算了满足电气间隙下的最小平行间距,以验证采用同走廊单避雷线方案的工程应用可行性。

Investigation of mortar corrosion by an acidophilic sulfur-oxidizing microorganism A.thiooxidans

The corrosion behavior of the acidophilic sulfur-oxidizing microorganism(ASOM)Acidithiobacillusthiooxidans(A.thiooxidans)on mortar was investigated for changes of medium and mortar,as well as for weight lossand surface morphology of mortar specimens.Weight loss analysis showed that mortar weight was reduced by(15.1±2.2)%after 56 d.Morphological surface analysis of mortar specimens showed weakly structured fibrous substances with2−100μm in size.The pH variations of the mortar surface and medium indicated that biogenic sulfuric acid had beenproduced by A.thiooxidans.The results prove that A.thiooxidans accelerated concrete corrosion and caused concretefailure.

Development and progress in polymer materials foranti-corrosion and anti-fouling applications:A review

Corrosion has always been a difficult problem that troubles and restricts the application and development ofengineering materials.By endowing coatings on metal surfaces with polymer material,it is possible to protect othermaterials from factors including acid and alkali,water vapor,bacteria.Therefore,it is necessary to summarize theresearch progress of polymer materials in the field of pollution and corrosion prevention in recent years.This articlesummarizes four types of polymer materials with good weather resistance:polyurethane(PU),polydimethylsiloxane(PDMS),polyvinylidene fluoride(PVDF),and polyvinylidene chloride(PVDC).These four polymer materials aresuitable for making polymer anti-corrosion or anti-fouling materials and each has its own characteristics.PU can firmlyadhere to various substrates,effectively protecting and extending their lifespan,but the environmentally friendly varietiescurrently used,namely water-borne polyurethanes(WPU),generally have poor mechanical properties.PDMS is nontoxicand has excellent hydrophobicity,but its static anti-fouling ability is insufficient when applied in the field of antifouling.PVDF has good chemical resistance and high mechanical properties,good UV resistance making it suitable foroutdoor use like in the marine environment.However,PVDF lacks flexibility after molding and its manufacturing cost isrelatively high.PVDC has excellent water vapor barrier properties,but poor adhesion to metal material surfaces.Therefore,researchers need to modify these four polymers when using them to solve the problem of corrosion orbiofouling.The article will review the research progress of four types of polymers in recent years from the perspectivesof anti-corrosion,anti-fouling,and a strategy named as self-healing that is beneficial for protecting polymer surfacesfrom mechanical damage,and summarize the modification methods adopted by researchers when applying thesematerials.Finally,a summary of the application and the prospects of these polymer materials are presented.

Effect of organic carbon sources on the anodic corrosion of magnesium AZ31B by sulfate-reducing prokaryote

Corrosion caused by sulfate-reducing prokaryotes(SRP)is an important cause of magnesium alloy anode failure in oil pipeline.In this study,the effects of Desulfovibrio sp.HQM3 on the corrosion behavior of AZ31B magnesium alloy anode in organic carbon sources with different contents in simulated tidal flat environment were analyzed using weight loss test,surface analysis and electrochemical analysis technologies.The results showed that the weight loss rate of coupons in low carbon sources contents(0%,1%,10%)was higher than that in 100%carbon sources.Electrochemical analyses showed that the corrosion current density(J_(corr))under low carbon sources contents was larger,while the charge transfer resistance(R_(ct))was lower,leading to a higher corrosion rate compared to those under 100%carbon sources content.Observations from scanning electron microscopy(SEM)and confocal laser scanning microscopy(CLSM)revealed more severe pitting corrosion on the alloy surface in the absence of carbon sources.In addition,a large number of nanowires were observed between bacteria on the alloy surface using SEM.Combined with thermodynamic calculations,it was demonstrated that the corrosion of coupons by Desulfovibrio sp.HQM3 in the absence of carbon sources was achieved through extracellular electron transfer.

Preface:Corrosion and protection in marine environment

The development of the marine economy,the protection of maritime rights,and the construction of a maritime power all rely on the support of various marine engineering facilities and equipment.However,when materials are used in marine environments,they face various issues of corrosion and biofouling.The occurrence of these problems not only significantly impacts the performance of materials but can also lead to substantial economic losses and even catastrophic or sudden safety incidents.Therefore,corrosion and prevention of various materials used in marine environments have always been challenging issues faced by researchers and engineering professionals.A deep understanding of the marine corrosion mechanisms of various materials,as well as the design and development of materials and technologies with excellent anti-corrosion properties,are the focal points and hot topics of interest for researchers in this field.