船舶推进轴的推力轴承特性分析

Thrust bearing is a key component of the propulsion system of a ship. It transfers the propulsive forces from the propeller to the ship’s hull, allowing the propeller to push the ship ahead. The performance of a thrust bearing pad is critical. When the thrust bearing becomes damaged, it can cause the ship to lose power and can also affect its operational safety. For this paper, the distribution of the pressure field of a thrust pad was calculated with numerical method, applying Reynolds equation. Thrust bearing properties for loads were analyzed, given variations in outlet thickness of the pad and variations between the load and the slope of the pad. It was noticed that the distribution of pressure was uneven. As a result, increases of both the outlet thickness and the slope coefficient of the pad were able to improve load bearing capability.     

基于流变特性的消石灰改性油污泥热解残渣沥青胶浆稳定性研究

为探究油污泥热解残渣沥青胶浆性能，实现其在道路工程中的应用，开展了消石灰改性油污泥热解残渣沥青胶浆稳定性与改性机理研究。通过扫描电镜和红外光谱试验分析油污泥热解残渣的理化性质；在此基础上通过沥青胶浆三大指标和黏度试验，解析消石灰改性油污泥热解残渣沥青胶浆的掺配比；通过沥青弯曲蠕变劲度(BBR)和动态剪切流变(DSR)等试验评价了消石灰改性油污泥热解残渣沥青胶浆水稳定性能及高低温流变性能；最后通过微观试验解析消石灰改性油污泥热解残渣沥青胶浆的微观界面特性和改性机理。结果表明：油污泥热解残渣存在以中大孔为主、微小孔为辅的多孔体系，经消石灰改性后的油污泥热解残渣与沥青之间存在较强的物理吸附作用与化学吸附作用，提高了油污泥热解残渣与沥青之间的黏结力；消石灰掺量占填料总质量的30%时，其对油污泥热解残渣沥青胶浆的改性效果最佳；当粉胶比为1.0,消石灰掺量为30%时，与普通矿粉沥青胶浆相比，其水煮后的质量损失率减小了18.2%;-6℃、-12℃、-18℃时的蠕变劲度分别降低18.3%、16.5%、5.4%;64℃、70℃、76℃、82℃时的抗车辙因子分别降低6.9%、7.4%、3.3%、1.4%。...     

A numerical study on the installation configuration design of compliant vertical access riser (CVAR) in deepwater

In oil and gas transportation, the compliant vertical access riser (CVAR) system conducts economic and operational advantages due to its special configuration. In this paper, the static performance of the CVAR is studied by an efficient numerical method. According to the unique configuration of the CVAR, the mathematical model is established based on minimum total potential energy principle. The equilibrium equations are discretized by finite difference method and then solved by Newton-Raphson technique. The accuracy of the numerical method is verified by OrcaFlex software. Detailed parametric analysis is carried out based on practical engineering requirements. The effects of buoyancy section's configuration including buoyancy factor, buoyancy section's length and buoyancy section's location, and external environmental factors including wellhead offset distance, water depth and current velocity on installation shape and mechanical properties of the CVAR are analyzed. The research shows that the presented numerical method has good applicability and flexibility for the early installation configuration design of marine risers which have no touchdown section but only one touchdown point and are equipped with multiple buoyancy blocks subjected to forces of different directions and magnitudes, such as CVARs.     

聚氨酯固-固相变材料改性沥青的流变性能与改性机理

为评价聚氨酯固-固相变材料(PUSSPCMs)作为沥青改性剂的潜力，确定PUSSPCMs对沥青流变性能的影响及作用机理，以不同质量分数的软段制备了PUSSPCMs(P70、P75、P80、P85和P90)及PUSSPCMs改性沥青，采用沥青调温性能、动态剪切流变(DSR)以及弯曲梁流变(BBR)试验测试了热性能和流变性能，并借助差示扫描量热(DSC)、红外光谱(FTIR)和原子力显微镜(AFM)分析了改性机理。结果表明：PUSSPCMs改性沥青较基质沥青的调温性能、抗变形和高温性能提高，低温性能降低；PUSSPCMs软段质量分数增加，PUSSPCMs改性沥青的调温性能和低温性能明显提高，抗变形和高温性能降低，其中P90沥青具有最好的调温性能和低温性能，而P70沥青的抗变形和高温性能最好；PUSSPCMs的储能放热性能优良，P90焓值较高而P70相变起始温度较低，焓值与PUSSPCMs改性沥青的调温性能高度相关。PUSSPCMs与沥青之间未产生新的官能团，为物理改性；PUSSPCMs对沥青微观形貌影响显著，弹性模量增大，但随着软段质量分数增加，沥青“蜂状结构”增多而周边相态差异降低，弹性...     

面向刚度设计的 GFRP 和 VRB/GFRP 混合层合板应变能密度分布研究

针对 VRB/GFRP混合结构刚度优化设计复杂而耗时这一问题，利用有限元法分析了 GFRP铺层角度和铺层数量、VRB厚度分布形式对两种层合板刚度特性及各组分应变能密度分布的影响规律。研究结果表明，应变能密度越小能表征更好的刚度性能；抗弯与抗凹工况下，采用# （0/90） 铺层角度、增加 GFRP铺层数量以及 VRB采用 0.9-1.8-0.9 mm 的厚度分布形式时，VRB/GFRP层合板各组分的应变能密度分布更加均匀，从而获得更好的刚度性能。     

Ultimate strength assessment of simply supported pitted platings: A new stochastic approach based on Monte Carlo simulation

The ultimate strength assessment of platings affected by random corrosion wastage is a key factor for the reliable design of new ships and the structural health monitoring of aged structures, as pitting corrosion wastage significantly affects the ultimate capacity of platings under compression. In this respect, significant efforts have been undertaken in the last decade to assess the ultimate strength drop-off of pitted platings under compression and several interpolating design formulas, based on a large number of FE simulations, have been developed. Nevertheless, current Rules and guidelines don't provide any explicit strength check criterion for pitted platings. Hence, the main aim of current research is the development of a new framework for the ultimate strength assessment of pitted platings, based on a stochastic approach and the endorsement of Monte Carlo simulation. A new formula, which allows evaluating the statistical properties of the plating ultimate strength in presence of random corrosion wastage, is developed. Subsequently, a benchmark study is carried out, to compare the new formula with the existing ones available in literature and a wide set of FE simulations, carried out by Ansys APDL. Current results are discussed, and the effectiveness of the new formula is verified.     

波纹钢板截面几何性质精确计算

为快捷、精确地计算波纹钢板截面几何性质，通过各截面几何性质的定义推导得出单位长度波纹钢板截面面积、惯性矩、截面模量、回转半径的精确计算公式，并将其编写为“波纹钢板截面几何性质计算器”程序。以两种波形为计算实例，将编写程序的计算结果与现有文献和CAD软件计算结果对比，结果表明：计算结果与CAD软件计算结果完全吻合，而现有文献中的计算结果均存在误差，为近似值。可见，推导的计算公式及编写的“波纹钢板截面几何性质计算器”程序可精确计算波纹钢板截面几何性质。