辽阳出口路现场热再生简析

重点介绍了辽阳出口路现场热再生沥青混合料的级配设计和施工工艺及施工过程中的质量控制要点。     

关于山区高速外业勘察中若干问题的探讨

近几年来,我国山区高速建设里程日益增加.因受复杂地形、地质条件的限制,山区高速的外业勘察具有其独有的关键技术难点,应在普通建设条件下的作业内容、作业方式的基础上,采取针对性的对策措施,确保外勘资料满足设计需求.     

复杂载荷下裂纹SIF计算的子模型技术

对船舶与海洋工程结构物进行疲劳评估,首先要通过子模型技术解决复杂应力场中裂纹应力强度因子(SIF)的计算问题。针对子模型技术实现过程繁杂且效率较低的问题,分别提出"逐周分层法","转换矩阵法"及"映射划分法"并基于VBA及APDL语言编写插件MPCarrangerV1.0,FEMcoortransferV1.0及CrackmapperV1.0,解决从Patran整体有限元模型到Ansys子模型时壳体单元间MPC创建低效、不同坐标系间节点位置转换困难及裂纹自由划分的局限性问题。基于DNV及ABS相关规范,以某B型LNG燃料舱的疲劳热点为例,对改进的子模型技术进行验证,结果表明经改进的子模型技术可成功施加合理边界条件并实现SIF的求解,可为子模型技术快速实现复杂载荷下裂纹SIF的准确计算提供参考。     

深海超高压环境模拟容器裂纹评定

深海超高压环境模拟容器用于模拟水下压力环境,其容器壁上承受反复载荷,容易产生疲劳裂纹.疲劳裂纹扩展是影响其断裂的主要因素.本文旨在分析半椭圆裂纹在老化的深海超高压环境模拟容器中的扩展行为,评估容器的安全性,因此对材料20MnMoNb钢的裂纹扩展特性进行了试验研究,首先考虑三角形和梯形加载情况,通过比较两组实验结果,考察了其材料对保载时间的敏感性.采用基于统一的裂纹扩展率模型的三维有限元方法进行了疲劳裂纹扩展计算,并通过CT试样的一组数值和实验结果进行了验证,最后建立了不同初始尺寸、展弦比和倾角的裂纹有限元模型,并根据裂纹在容器内壁的容许深度准则,计算了容器的剩余寿命.其分析结果可为深海超高压环境模拟容器可靠性评估提供参考.     

爆炸硬化高锰钢组合辙叉水平裂纹伤损分析

爆炸硬化高锰钢组合辙叉是近几年针对重载铁路使用条件开发的一种新型固定型辙叉产品,在批量上道使用后,水平裂纹伤损发生频次逐渐增加,引起广泛的关注。对水平裂纹伤损产生的原因进行分析,并提出多项改进措施。通过改进措施的实施,在朔黄线取得了较好的改进效果。实际结果表明,通过不断改进工艺、提高质量、加强维护,爆炸硬化高锰钢组合辙叉能够实现通过总重3亿t以上的目标。     

Hydroelastic analysis of oblique irregular waves with a pontoon-type VLFS edged with dual inclined perforated plates

The fluid-structure interaction of oblique irregular waves with a pontoon-type very large floating structure (VLFS) edged with dual horizontal/inclined perforated plates has been investigated in the context of the direct time domain modal expansion theory. For the hydroelastic analysis, the boundary element method (BEM) based on time domain Kelvin sources is implemented to establish water wave model including the viscous effect of the perforated plates through the Darcy’s law, and the finite element method (FEM) is adopted for solving the deflections of the VLFS modeled as an equivalent Mindlin thick plate. In order to enhance the computing efficiency, the interpolation-tabulation scheme is applied to assess rapidly and accurately the free-surface Green function and its partial derivatives in finite water depth, and the boundary integral equation of a half or quarter VLFS model is further established taking advantage of symmetry of flow field and structure. Also, the numerical solutions are validated against a series of experimental tests. In the comparison, the empirical relationship between the actual porosity and porous parameter is successfully applied. Numerical solutions and model tests are executed to determine the hydroelastic response characteristics of VLFS with an attached anti-motion device. This study examines the effects of porosity, submerged depth, inclined angle and gap distance of such dual perforated anti-motion plates on the hydroelastic response to provide information regarding the optimal design. The effects of oblique wave angle on the performance of anti-motion and hydroelastic behavior of VLFS are also emphatically examined.     

向量法在不规则隧道边仰坡面积计算中的应用

根据隧道边仰坡三维坐标测量数据,通过计算边仰坡斜面和投影水平面的法向量,进而计算两面之间夹角的方法,反算边仰坡斜面面积,在类似不规则隧道边仰坡等斜面面积计算中具有广泛的应用价值。     

基于职业能力的高职会计实践教学体系的重构

文章通过分析高职会计专业构建实践教学体系的必要性入手，分析会计职业能力的内涵，从会计课程体系、实训项目体系、实训项目教学设计三个方面探索了现代高职会计实践教学体系的构建，拓展会计实践教学的实训资源，完善构建实践教学体系的机制。     

递进式连锁经营管理专业实践教学改革研究——基于加盟创业项目视角

连锁经营管理专业人才培养目标大多定位在一线服务员或基层管理者，所培养的学生必须具备较强的连锁专业能力和创业能力，而大多数高职院校培养出来的学生在这些方面所表现出来的能力却差强人意，尤其是创业能力方面。本文提出将加盟创业项目贯穿于连锁经营管理实践教学全过程，按照“仿真训练-校内孵化-校内模拟-市场全真”四个阶段，形成一个递进式的实践教学流程，从而促使学生的专业能力和创业能力实现递进式提升。     

Design,analysis and performance evaluation of a third order distributed protocol for platooning in the presence of time-varying delays and switching topologies

This paper is concerned with the problem of designing a decentralized consensus protocol for platooning of non-identical vehicles in the presence of heterogeneous time-varying communication delays. The proposed control protocol makes use of a state feedback and to this aim drivetrain dynamics are modeled as third-order linear systems. Necessary and sufficient conditions for convergence and exponential stability, derived by using an appropriate Krasovskii functional, demonstrate the ability of the platoon in reaching the required regime with an exponentially bounded behavior. The proposed LMI-based approach allows to estimate both delay margin and decay rate. Moreover, convergence is proven under switching communication network topologies by means of a Lyapunov-Razumikhin function, and the assessment of a string stable behavior has been also theoretically investigated. High-fidelity simulations with Plexe show the effectiveness of the theoretical results in different driving conditions and in the presence of external disturbances and communication impairment. Different communication channel models are used in the validation stage to further prove robustness of the proposed methodology with respect hard delay and packets losses.