The effects of process parameters on the depth-to-width ratio （D/W） of flux-cored wire underwater wet welding with a certain type of homemade .flux-cored wire are studied. It is found that the welding .speed, wire f...The effects of process parameters on the depth-to-width ratio （D/W） of flux-cored wire underwater wet welding with a certain type of homemade .flux-cored wire are studied. It is found that the welding .speed, wire feeding speed and torch oscillating amplitude hare significant effects on the dopth-to-width ratio （D/W） of welds. The D/W ratio of welds increases significantly with the increase of welding speed without the oscillating of welding torch. It increased （from 0. 14 to 0. 26 ） with the increase of wire feeding speed while the torch oscillating. And it decreased linearly with the increase of torch oscillating amplitude. However, the influelwe of oscillating speed, wire extension and welding voltage on the D/W ratio of welds was not obvious.展开更多
Bed morphology is the result of a dynamic response to a complex meandering river system. It is an important factor for the further development of river. Based on the meandering river characterized by a large depth-to-...Bed morphology is the result of a dynamic response to a complex meandering river system. It is an important factor for the further development of river. Based on the meandering river characterized by a large depth-to-width ratio, a theoretical model is established with the coupling of Navier-Stokes （N-S）~ sediment transport, and bed deformation equations. The flow characteristics and bed response of river are obtained with the perturbation method. The research results show that, under the effect of two- dimensional flow disturbance, the bars and pools present the regular response. For a given sinuousness, the amplitude of the bed response can be used as a criterion to judge the bedform stability. The effects of the Reynolds number, disturbance wavenumber, sinuousness, and bed morphology gradient on the bed response development are described.展开更多
研究地下内衬岩洞(Lined Rock Caverns,LRC)储气库的衬砌开裂特征,为该类储气库的设计和工程应用提供参考。通过应用ABAQUS有限元软件建立地下大罐式内衬高压储气库模型,使用显示动力分析研究横向配筋率、纵向配筋率、埋深、储气压力等...研究地下内衬岩洞(Lined Rock Caverns,LRC)储气库的衬砌开裂特征,为该类储气库的设计和工程应用提供参考。通过应用ABAQUS有限元软件建立地下大罐式内衬高压储气库模型,使用显示动力分析研究横向配筋率、纵向配筋率、埋深、储气压力等参数对衬砌开裂特征的影响。结果表明:衬砌外表面最大裂缝宽度大于内表面,而衬砌内表面存在更多的细小裂缝;随着横向配筋率的提高,混凝土衬砌中内外表面裂缝宽度逐渐减小,贯穿性裂缝数量减小,裂缝平均间距减小。但当横向配筋率超过0.16%,裂缝宽度变化不再显著;埋深越大,地应力越大,衬砌产生的环向拉应力越小,衬砌裂缝宽度越小。建议适当增大横向配筋率和储气库埋深,减小储气压力来抑制衬砌裂缝的开展,而纵向钢筋按构造配筋即可。展开更多
文摘The effects of process parameters on the depth-to-width ratio （D/W） of flux-cored wire underwater wet welding with a certain type of homemade .flux-cored wire are studied. It is found that the welding .speed, wire feeding speed and torch oscillating amplitude hare significant effects on the dopth-to-width ratio （D/W） of welds. The D/W ratio of welds increases significantly with the increase of welding speed without the oscillating of welding torch. It increased （from 0. 14 to 0. 26 ） with the increase of wire feeding speed while the torch oscillating. And it decreased linearly with the increase of torch oscillating amplitude. However, the influelwe of oscillating speed, wire extension and welding voltage on the D/W ratio of welds was not obvious.
文摘Bed morphology is the result of a dynamic response to a complex meandering river system. It is an important factor for the further development of river. Based on the meandering river characterized by a large depth-to-width ratio, a theoretical model is established with the coupling of Navier-Stokes （N-S）~ sediment transport, and bed deformation equations. The flow characteristics and bed response of river are obtained with the perturbation method. The research results show that, under the effect of two- dimensional flow disturbance, the bars and pools present the regular response. For a given sinuousness, the amplitude of the bed response can be used as a criterion to judge the bedform stability. The effects of the Reynolds number, disturbance wavenumber, sinuousness, and bed morphology gradient on the bed response development are described.
文摘研究地下内衬岩洞(Lined Rock Caverns,LRC)储气库的衬砌开裂特征,为该类储气库的设计和工程应用提供参考。通过应用ABAQUS有限元软件建立地下大罐式内衬高压储气库模型,使用显示动力分析研究横向配筋率、纵向配筋率、埋深、储气压力等参数对衬砌开裂特征的影响。结果表明:衬砌外表面最大裂缝宽度大于内表面,而衬砌内表面存在更多的细小裂缝;随着横向配筋率的提高,混凝土衬砌中内外表面裂缝宽度逐渐减小,贯穿性裂缝数量减小,裂缝平均间距减小。但当横向配筋率超过0.16%,裂缝宽度变化不再显著;埋深越大,地应力越大,衬砌产生的环向拉应力越小,衬砌裂缝宽度越小。建议适当增大横向配筋率和储气库埋深,减小储气压力来抑制衬砌裂缝的开展,而纵向钢筋按构造配筋即可。
