Effects of Repair Grouting and Jacketing on Corrosion Concrete Using Ultrasonic Method

Concrete is one of the most important elements in building construction.However,concrete used in construction is susceptible to damage due to corrosion.The influence of corrosive substances causes changes in the reinforcing steel and affects the strength of the structure.The repair method is one approach to overcome this problem.This research aims to determine the effect of grouting and jacketing repairs on corroded concrete.The concrete used has dimensions of 15 cm×15 cm×60 cm with planned corrosion variations of 50%,60%,and 70%.The test objects were tested using the Non-Destructive Testing(NDT)method using Ultrasonic Pulse Velocity(UPV).The test results show that the average speed of normal concrete is 5070 m/s,while the lowest average speed is 3070 m/s on the 70%planned corrosion test object.The test object was then given a load of 1600 kgf.At this stage,there is a decrease in speed and wave shape with the lowest average speed obtained at 2753 m/s.The repair method is an effort to restore concrete performance by using grouting and jacketing.Grouting is done by injecting mortar material into it.Jacketing involves adding thickness to the existing concrete layer with additional layers of concrete.After improvements were made,there was an improvement in the UPV test,with a peak speed value of 4910 m/s.Repairing concrete by filling cracks can improve concrete continuity and reduce waveform distortion,thereby increasing wave propagation speed.

Wind-Vortex-Induced Vibrations of a Deepwater Jacket Pipe and Vibration Suppression Using a Nonlinear Energy Sink

The purpose of this study is to investigate the suppression effect of a nonlinear energy sink(NES)on the wind-vortex-induced pipe vibration and explore the influence of damping,stiffness,and NES installation position on the suppression effect.In this work,the wind-vortex-induced vibration of an elastic pipe of a deepwater jacket was studied,and vibrations were suppressed by using an NES.A van der Pol wake oscillator was used to simulate vortex-induced force,and the dynamic equation of the pipe considering the NES was established.The Galerkin method was applied to discretize the motion equation,and the vortex-induced vibration(VIV)of the pipe at reduced wind speeds was numerically analyzed.The novelty of this research is that particle swarm optimization was used to optimize the parameters of the NES to improve vibration suppression.The influence of the installation position,nonlinear stiffness,and damping parameters of the NES on vibration suppression was analyzed.Results showed that the optimized parameter combinations of the NES can effectively reduce wind-vortex-induced pipe vibration.The installation position of the NES had a significant effect on vibration suppression,and the midpoint of the pipe was the optimal NES installation position.An increase in stiffness or a 10% decrease in damping may cause vibration suppression failure.The results of this study provide some guidance for VIV suppression in deepwater jacket pipes.

Lateral ring compression test applied to a small caliber steel jacket:Identification of a constitutive model

The evolution of threats and scenarios requires continuous performance improvements of ballistic protections for armed forces.From a modeling point of view,it is necessary to use sufficiently precise material behavior models to accurately describe the phenomena observed during the impact of a projectile on a protective equipment.In this context,the goal of this paper is to characterize the behavior of a small caliber steel jacket by combining experimental and numerical approaches.The experimental method is based on the lateral compression of ring specimens directly machined from the thin and small ammunition.Various speeds and temperatures are considered in a quasi-static regime in order to reveal the strain rate and temperature dependencies of the tested material.The Finite Element Updating Method(FEMU)is used.Experimental results are coupled with an inverse optimization method and a finite element numerical model in order to determine the parameters of a constitutive model representative of the jacket material.Predictions of the present model are verified against experimental results and a parametric study as well as a discussion on the identified material parameters are proposed.The results indicate that the strain hardening parameter can be neglected and the behavior of the thin steel jacket can be described by a modeling without strain hardening sensitivity.

The next GORE-TEX for jackets?

Columbia is a world-renowned manufacturer of outdoor products.Its product range covers all aspects of outdoor equipment such as jackets,down jackets,outdoor footwear,backpacks and accessories.In the outdoor industry,Columbia was the first brand to propose a three-in-one garment design concept.This practical design has since been adopted by almost every outdoor brand.The Columbia Jacket is positioned for urban outdoor recreation.Its rugged materials and design make it suitable for low-altitude outdoor sports as well as urban commuting.

Upgrading jackets for spring

When the gentle breeze of spring starts to fill the air,it's often a time of transition,where the chill of winter gives way to the warmth of the coming season.However,for those who love the outdoors,spring can still present its own set of challenges,especially when it's time to choose the right jacket.Whether you're hiking in the hills,exploring the trails,or just taking a leisurely walk in the park,having a jacket that offers the perfect blend of warmth,comfort,and breathability is crucial.We'll delve into the various options available for jackets that are perfect for the outdoors in spring.

Why own an Arc’teryx jacket?

Arc’teryx’s Beta AR Jacket sets a new bar in terms of what a mainstream outdoor jacket can do.You’ll turn around and charge headfirst into a rainstorm with this fully impermeable outer layer that packs in everything you need to lock in your core and stay dry.Unlike some jackets,the best part is that this jacket also pays dividends in sunny weather.While it’s designed for nasty weather,it stays comfortable when the storm passes away.The company’s high-tech waterproof membrane simultaneously wicks moisture and finally kicks that classic clammy raincoat feeling to the curb.

基于工程临界评定(ECA)的海洋油气导管架平台结构裂纹评定

针对已发现结构裂纹的海洋油气导管架平台,基于工程临界评定(ECA)技术,形成适用的结构完整性评价及维修周期策略制定方法,并对某导管架平台进行了案例分析。使用莫里森方程(Morison equation)对目标平台进行了水动力学分析,估算了平台关键节点的极限载荷。通过有限元分析方法及热点应力线性外推法对关键节点进行了热点应力评估。通过帕里斯公式(Paris'law)对关键节点处裂纹扩展行为进行了相关模拟,求解目标裂纹尖端应力强度因子。通过失效评定图(FAD)对相关裂纹进行了ECA评估,给出了临界裂纹范围。结合临界裂纹深度和裂纹扩展关系,给出参考维修周期。结果表明:管架水平杆与立管相连节点为易于受疲劳损伤杆件。通过失效评定,该结构裂纹深度方向失效以塌陷失效为主,裂纹长度方向存在塌陷失效和裂纹失效可能。针对案例分析中平台,建议考虑临界裂纹深度5.3 mm,临界裂纹半宽长度9.8 mm。如发现0.5~2.0 mm的裂纹,建议在13.2~5.2 h内完成维修。该方法可推广应用于周边海域相似海洋油气平台已发现裂纹评定。

Seismic strengthening of reinforced concrete columns damaged by rebar corrosion using combined CFRP and steel jacket

In order to study the effectiveness of combined carbon fiber-reinforced polymer （CFRP） sheets and steel jacket in strengthening the seismic performance of corrosion-damaged reinforced concrete （RC） columns, twelve reinforced concrete columns are tested under combined lateral cyclic displacement excursions and constant axial load. The variables studied in this program include effects of corrosion degree of the rebars, level of axial load, the amount of CFRP sheets and steel jacket. The results indicate that the combined CFRP and steel jacket retrofitting technique is effective in improving load-carrying, ductility and energy absorption capacity of the columns. Compared with the corrosion-damaged RC column, the lateral load and the ductility factor of many strengthened columns increase more than 90% and 100%, respectively. The formulae for the calculation of the yielding load, the maximum lateral load and the displacement ductility factor of the strengthened columns under combined constant axial load and cyclically increasing lateral loading are developed. The test results are also compared with the results obtained from the proposed formulae. A good agreement between calculated values and experimental results is observed.

有限域上快速分块Jacket变换

提出了一种在有限域上的简单上闭链分块逆Jacket变换(CBIJT)。为将高阶的上闭链逆Jacket矩阵(CBIJM)因式分解成单位矩阵和低阶稀疏矩阵,考虑运用带来快速变换的连续结构来减少计算负荷。采用类似的递归方式分析两个CBIJT,即单维和双维CBIJT。这两个CBIJT为单位矩阵和低阶CBIJT的多重Kronecker积。

摩托车发动机冷却水套流场分析及水套结构优化

对摩托车单缸发动机、双缸发动机及四缸发动机冷却水套内冷却液循环流动过程进行了分析,研究了水套内冷却液流速及水套壁面换热系数分布,基于冷却液循环流动路径分析进行了冷却水套结构优化。结果表明:单缸发动机排气侧及鼻梁区冷却液流速较低,鼻梁区存在零流速区域;双缸发动机两缸冷却液流速分布不均匀,两缸间衔接处中间区域冷却液流速较低;四缸发动机各缸也存在冷却液流速不均匀的问题。通过冷却液循环流动路径分析明确了各缸垫上水孔冷却液的流动方向及其作用,结合高温区域需重点冷却的设计准则对3种类型发动机冷却水套的缸垫上水孔布局、水套局部流通面积进行了优化,优化后3种类型发动机冷却水套排气侧及鼻梁区等高温区域的冷却液流速都达到流速不低于1.5 m/s的要求,各缸冷却液流速差异减小。经发动机热平衡验证,3种类型发动机冷却水套结构优化都可有效降低缸头火花塞垫片温度及减小各缸火花塞垫片温度的差异,验证了水套结构优化方案的有效性。

Analyzing the safety of removal sequences for piles of an offshore jacket platform

An inevitable consequence of the development of the offshore petroleum industry is the eventual obsolescence of large offshore structures. Proper methods for removal of decommissioned offshore platforms are becoming an important topic that the oil and gas industry must pay increasing attention to. While removing sections from a decommissioned jacket platform, the stability of the remaining parts is critical The jacket danger indices D ~ and Ds defined in this paper are very useful for analyzing the safety of any procedure planned for disassembling a jacket platform. The safest piles cutting sequence can be determined easily by comparing every column of Do and Ds or simply analyzing the figures of every row ofD o and D,.

考虑非线性腐蚀效应的海上风电导管架结构承载特性分析

海上风机运行30年后,位于飞溅区的导管架结构在海水干湿交替作用下产生严重的腐蚀现象,导致钢管壁厚变薄,承载性能下降。因此,开展考虑腐蚀效应的导管架结构承载特性研究是海上风电结构设计的重要研究内容。本文基于钢管桩非线性腐蚀模型,采用SACS (structural analysis computer software)数值分析软件分析飞溅区导管架钢管结构腐蚀程度对导管架杆件受力及变形的影响规律,得到以下结论:(1)腐蚀程度对导管架杆件轴力影响较小,对杆件剪应力影响显著,经过30年腐蚀后,轴力平均减小1.50%,剪应力增大70.57%;(2)腐蚀对导管架杆件节点的水平位移影响显著,对竖向位移影响则相对较小,经过30年腐蚀后,水平位移增大了11.12%,竖向位移减小了3.96%;(3)腐蚀对导管架结构中的下压杆的位移影响大于上拉杆,经过30年腐蚀后,位于下压杆的竖向位移是上拉杆的9倍。本文的研究成果可为导管架结构的防腐设计提供参考。

考虑溜桩效应的海上风电导管架基础稳定性分析

导管架桩基沉桩及打桩过程中遇到软弱土层会发生溜桩现象,导致桩周土体重塑,侧摩阻力降低,从而影响桩基稳定性。因此,开展考虑溜桩效应的导管架基础承载特性研究对于海上风电工程安全至关重要。以东海某风电场为工程背景,采用理论计算和数值模拟相结合的方法,分析溜桩效应对导管架基础承载特性的影响规律,得到以下结论:沉桩过程中发生溜桩,深度为19.6 m;打桩过程中发生溜桩,深度为19.0 m;溜桩对上拔桩和下压桩的承载特性影响差别不大;侧摩阻力折减系数对导管架桩基挠度影响显著,最大增幅达到309.1%;对导管架桩基弯矩影响相对较小,最大增幅为57.6%。

基于AutoCAD参数的男装O型夹克样板自动生成

为探索AutoCAD参数化设计在休闲男装品类中大规模个性化定制中的适用性,以休闲男装经典款式之一的O型夹克为研究对象,采用椭圆弧及双圆弧拟合原理绘制袖窿及领口弧线,构建O型夹克结构的参数化模型,主要包括衣身原型各对象的标注约束及几何约束、原型初始尺寸及参数调整量;然后根据基本样板的结构特征调整参数值,自动生成变款纸样;最后借助CLO3D软件虚拟展示成衣效果并验证O型夹克参数化结构模型的准确性。结果验证了AutoCAD参数化功能在休闲男装品类个性化定制中的适用性,提高了参数化在男装设计中的应用广度以及在个性化定制中的快速反应能力。

废弃导管架沉降过程动力学分析

针对当前海上石油平台退役后处置的问题,将废弃导管架再利用为人工鱼礁成为了最具可行性的方案之一。为避免切除后的导管架在沉降时产生结构破坏,对其布放后的动力学进行了分析。基于莫里森方程推导了水动力学模型,建立导管架与海床平面的接触模型及碰撞模型,对导管架沉降过程进行了动力学研究。同时,利用动力学软件ADAMS模拟了导管架在3种不同初始倾角下的沉降过程,采用有限元分析系统ANSYS Workbench对着底后的导管架进行强度分析。结果表明,随着导管架的投放倾角的增大,沉降的稳定速度减小;底棱触底时冲击力较小但应力更大,约为15 MPa,尤其在中部区域较为明显。研究可为合理规划导管架的布放和设计提供参考,也为优化导管架的布放过程提供理论支撑。

应用CUDA加速免疫算法——Jacket与Matlab实现

作为继遗传算法后新兴的一种人工智能算法——免疫算法最近几年在理论研究和工程应用方面得到了极大的关注和发展,但由于免疫算法本身机理的并行性使得其在通用CPU上进行测试和运行时效率低下,不利于评价算法的性能。通过通用并行计算架构CUDA使用GPU运行则更符合算法本身机理,大幅节省运行时间,降低硬件成本。

海上升压站导管架基础钢管桩数值模拟分析

海上升压站场地岩溶问题对升压站整体稳定性乃至选址有较大影响。针对北方某海上风电项目海上升压站场地岩溶问题,采用设计软件PLAXIS 3D模拟计算桩底应力及土体位移,其中土体模型采用HS small模型。结果表明:应力、应变及位移对海上升压站的安全运营影响均可忽略不计,升压站无需移位。

Reliability-Based Design for Jacket Platform Under Extreme Loads

In this paper, reliability analysis for the offshore jacket platform with the interaction of structure- pile- soil under extreme environmental loads is carried out. The inherent uncertainties of the environmental load, foundation soil, platform itself, and calculating models are evaluated. The action of extreme loads on the offshore platform is modeled as a function of extreme wave height. The system capacity of the whole platform is determined by nonlinear pushover analysis, and the relevant probability property is obtained by the simulation method. The reliability model for the whole jacket platform is described as the relationship between the load and resistance based on the offshore design codes. The reliability of whole platform is calculated by the analytical method and the importance sampling method on the basis of a case study for a tripod jacket platform.

一种新的快速反循环分块Jacket变换

受反循环矩阵和Jacket变换的启发,给出反循环分块Jacket变换对应的矩阵结构,进而获得了其任意阶的构造方法,丰富了Jacket变换的内容.随后基于克罗内克积及高阶反循环分块Jacket矩阵对应的置换矩阵,提出了该Jacket变换的前后向矩阵的一种递归形式的快速构造与分解算法.相比直接计算方法,该快速算法拥有更低的计算复杂度.而且本文提出的构造方法及快速算法也可以应用到其它具有类似结构的其它反循环分块Jacket变换中.

Calibration of LRFD Format for Steel Jacket Offshore Platforms in China Offshore Area(1) :Statistical Parameters of Loads and Resistances

The statistical characteristics and parameters of loads and resistances are systematically studied for the development of probabilistic limit state design method for steel jacket offshore platforms in the China offshore area. The mean value, standard variance and distribution pattern of resistances and loads in different base perieds are presented. The statistical parameters of structural member resistance, self-weight, deck live load, and environmental loads such as wind, wave, current and ice, which are drawn on a large amount of observatian data of offshore environmental factors, and the design data of platforms in China Bohai Sea form the data set, providing a necessary basis for the calibration of load and resistance factors to realize the reliability-based design of jacket platform structures.