自密实混凝土浇筑成型方向对 新老混凝土界面黏结抗剪强度的影响

针对自密实混凝土加固既有混凝土结构时存在不同方位的黏结界面,为研究其对新老混凝土界面剪切强度的影响,设计具有不同混凝土浇筑成型方向的Z型黏结试件进行直剪试验,探究自密实混凝土浇筑成型方向、混凝土强度和界面处理方式等对黏结试件破坏形式和抗剪强度的影响,并探讨不同浇筑成型方向影响下新老混凝土黏结界面抗剪强度计算方法。研究结果表明:混凝土浇筑成型方向对界面抗剪强度影响显著,新混凝土从老混凝土顶面浇筑的效果最好,侧面浇筑次之,底面浇筑最差,差值最大多达到顶面浇筑试件抗剪强度的50%。一定范围内增大新混凝土强度能有效提高黏结界面抗剪强度,底面浇筑时效果尤为明显;当新老混凝土强度相差较大时,继续提高新混凝土强度作用不大。基于本试验结果,建议新老混凝土强度差宜控制在2个标号以内。界面处理方式对其抗剪强度的影响依赖于新老混凝土强度和新混凝土浇筑成型方向。本试验中,II类界面对于强度相同的新老混凝土界面抗剪强度影响不大,但能提高不同强度的新老混凝土界面抗剪强度,尤其是底面浇筑和侧面浇筑的界面。     

Study on Factors Affecting Springback and Application of Data Mining in Springback Analysis

Springback of sheet metal induced by elastic recovery is one of major defects in sheet metal forming processed. Springback is influenced by many factors including properties of the sheet material and processing conditions. In this paper, a springback simulation was conducted and comparisons between the results based on different processing variables were illustrated. The discovery of knowledge of the effects of geometry and process parameters on springback from FEM results becomes increasingly important, as the number of numerical simulation has grown exponentially. Data mining is an effective tool to realize knowledge discovery in simulation results. A datamining algorithm, rough sets theory (RST), was applied to analyze the effects of process parameters on springback in U-bending.     

Phase Behaviors in Bi-phase Simulation of Powder Segregation in Metal Injection Molding

Powder segregation induced by mold filling is an important phenomenon that affects the final quality of metal injection molding （MIM）. The prediction of segregation in MIM requires a bi-phase flow model to describe distinctly the flows of metallic powder and polymer binder. Viscous behaviors for the flows of each phase should hence be determined. The coefficient of interaction between the flows of two phases should also be evaluated. However, only viscosity of the mixed feedstock is measurable by capillary tests. Wall sticking is supposed in the traditional model for capillary tests, while the wall slip is important to be taken into account in MIM injection. Objective of the present paper is to introduce the slip effect in bi-phase simulation, and search the suitable way to determine the viscous behaviors for each phase with the consideration of wall slip in capillary tests. Analytical and numerical methods were proposed to realize such a specific purpose. The proposed method is based on the mass conservation between the capillary flows in mono-phase model for the mixed feedstock and in bi-phase model for the flows of two phases. Examples of the bi-phase simulation in MIM were realized with the software developed by research team. The results show evident segregation, which is valuable for improving the mould designs.     

沥青稳定碎石排水基层(ATPB)混合料设计

对沥青稳定碎石排水基层混合料设计进行了探讨,提出了相应的成型方法、级配范围、沥青用量确定方法、性能验证指标等,可供同类项目ATPB混合料设计时参考。     

美国和法国旋转压实法对高模量混合料 的影响比较研究

法国高模量混合料设计采用的旋转压实方法,与我国设计采用的美国旋转压实方法有明显的差别。本研究通过对美国和法国旋转压实法对高模量混合料的影响比较研究,发现两种压实方法不存在对应关系,对于高模量混合料,用美国旋转压实替代法国旋转压实还有待于实践的进一步验证。     

振动成型法在水泥粉煤灰稳定碎石基层中的应用

文章以强度和模量试验为依据,采用振动成型法对水泥粉煤灰稳定碎石进行级配研究,并将研究成果成功应用于连霍高速公路（G30）西安至宝鸡段改扩建工程。工程实践表明,经优化设计的水泥粉煤灰稳定碎石基层表现出良好的路用性能,可供类似工程设计参考。     

冷弯成型局部大变形测试装置的设计与研究

冷弯成型变形复杂，事先难以预测其变形效果。根据冷弯成型的特点和变形规律设计出基于万能实验机上的局部大变形测试装置，并应用此装置对冷弯成型过程进行回弹分析，为冷弯成型理论分析和使用ANSYS／LS-DYNA对冷弯成型分析提供科学依据。     

JU2000E型自升式钻井平台钻台制造工艺技术

以钻井平台核心结构之一的钻台结构作为研究对象,通过分析其功能结构、核心组件的装配关系,研究、总结钻台用高强度结构钢的焊接变形,不断优化钻台组件及拼装工艺流程,成功实现了自升式钻井平台钻台结构模块的建造工作。通过优化革新钻台吊装工艺建造方案,实现了钻台设备完整性吊装工作。