Installation Of Sleeve Research Articles

Research on Key Technology of Mechanical Construction of Connecting Passages

Conventional connecting passages construction usually uses mining method with freezing or grouting method of reinforcement, generally has a long construction period, high construction risk, costly problems, which has an urgent need for a mechanical way of construction technology to improve the speed and quality of construction. The critical technologies for the mechanical construction of connecting passages mainly include the design of the main tunnel and the connecting-passage segment, TBM fully enclosed launching and receiving, the waterproof design, and the design of the built-in pump chamber of the TBM. Its construction process mainly includes TBM assembly, sleeve installation, breaking of the tunnel door, the tunnel boring, the machine receiving, and the fabrication of the tunnel door seal. Based on the above vital technologies analysis, this paper demonstrates the significant advantages of the mechanical construction of the connecting passage with practical construction cases, which provides an essential reference for the subsequent research.

Recent Advances of GFRP Composite Cross Arms in Energy Transmission Tower: A Short Review on Design Improvements and Mechanical Properties.

Currently, pultruded glass fibre-reinforced polymer (pGFRP) composites have been extensively applied as cross-arm structures in latticed transmission towers. These materials were chosen for their high strength-to-weight ratio and lightweight characteristics. Nevertheless, several researchers have discovered that several existing composite cross arms can decline in performance, which leads to composite failure due to creep, torsional movement, buckling, moisture, significant temperature change, and other environmental factors. This leads to the composite structure experiencing a reduced service life. To resolve this problem, several researchers have proposed to implement composite cross arms with sleeve installation, an addition of bracing systems, and the inclusion of pGFRP composite beams with the core structure in order to have a sustainable composite structure. The aforementioned improvements in these composite structures provide superior performance under mechanical duress by having better stiffness, superiority in flexural behaviour, enhanced energy absorption, and improved load-carrying capacity. Even though there is a deficiency in the previous literature on this matter, several established works on the enhancement of composite cross-arm structures and beams have been applied. Thus, this review articles delivers on a state-of-the-art review on the design improvement and mechanical properties of composite cross-arm structures in experimental and computational simulation approaches.

Phononic crystal pipe with periodically attached sleeves for vibration suppression

Flexural vibration of pipes is a common problem in many practical engineering applications, which usually influences the operating state of the system or even causes damage of the equipment. In the present work, an easy-realized design of phononic crystal pipe is proposed to implement vibration suppression by directly upgrading the bare pipe with attached sleeves without replacing the original structure. Based on the mechanism of Bragg scattering, flexural wave bandgap could be obtained with the periodical changing in cross section of the sleeved pipe. Sleeve installation generates both added mass and added stiffness simultaneously, which leads to the parabolic variations in edge frequencies of the bandgap against sleeve dimensions. Asynchronous recovery of the two frequency loci makes the bandgap close up when the sleeve covers about half length of the unit cell. This feature is not observed in analyses of binary phononic crystal pipes. Equivalent models are proposed to discuss the predicted variations, and the singular dependence of closure of bandgap on sleeve length is theoretical explained. Experiments are carried out to validate the feasibility of attaching sleeves for flexural vibration suppression of pipes. The proposed design could effectively attenuate the vibration energy with the intended bandgap.

Creep Properties and Analysis of Cross Arms' Materials and Structures in Latticed Transmission Towers: Current Progress and Future Perspectives.

Fibre-reinforced polymer (FRP) composites have been selected as an alternative to conventional wooden timber cross arms. The advantages of FRP composites include a high strength-to-weight ratio, lightweight, ease of production, as well as optimal mechanical performance. Since a non-conductive cross arm structure is exposed to constant loading for a very long time, creep is one of the main factors that cause structural failure. In this state, the structure experiences creep deformation, which can result in serviceability problems, stress redistribution, pre-stress loss, and the failure of structural elements. These issues can be resolved by assessing the creep trends and properties of the structure, which can forecast its serviceability and long-term mechanical performance. Hence, the principles, approaches, and characteristics of creep are used to comprehend and analyse the behaviour of wood and composite cantilever structures under long-term loads. The development of appropriate creep methods and approaches to non-conductive cross arm construction is given particular attention in this literature review, including suitable mitigation strategies such as sleeve installation, the addition of bracing systems, and the inclusion of cross arm beams in the core structure. Thus, this article delivers a state-of-the-art review of creep properties, as well as an analysis of non-conductive cross arm structures using experimental approaches. Additionally, this review highlights future developments and progress in cross arm studies.

MINIMIZATION OF DEFECT IN THE FORM OF LONGITUDINAL FOLDS AT THE END SECTIONS OF THIN-WALLED SEAMLESS PIPES DURING ROLLING AT AUTOMATIC MILL

During rolling of thin-walled seamless pipes at the rear ends, a defect in the form of end folds occurs, which leads to an increase in the consumption coefficient of the metal. To identify the causes of the formation of this defect, the mathematical modeling of rolling processes in the QForm VX software was carried out. The simulation results showed that the main factor in the formation of end folds at the rear ends of the pipe billets is an increased relative compression along the wall of the pipe billet in the first pass, which leads to flattening of the rear end of the pipe billet and formation of longitudinal folds. To prevent the formation of end folds, it is proposed to install an additional sleeve with a mandrel. As a result of the research, the values of relative compressions were determined, at which a defect is formed for rolling with a new mandrel installation option. It was found that with relative compression along the wall in the first passage from 30.0 %, a defect in the form of folds (“fins”) at the rear end of the pipe billet is formed. With a relative compression of the wall in the first passage up to 39.4 %, the installation of sleeves reduces the formation of “fin” defects at the rear end of the pipe billet; with a relative compression from 39.4 % to 41.8 %, its installation does not prevent the formation of these defects. The optimal distance between the mandrel of the automatic mill and the sleeve is 20–30 mm

Analysis of the Application of Occupational Health and Safety Risk Management at Pt. W Year 2022

Risk management is a systematic method of looking at risks and ensuring appropriate action on those risks. It is a means of identifying sources of risks and uncertainties and being able to predict the consequences that will arise and develop the reactions that should be tried to address those risks. This research aims to obtain in -depth information on the analysis of the application of occupational safety and health risk management in PT.W in 2022. This research was conducted using a qualitative research design by conducting in -depth interviews, to 5 people, namely 1 person HSE Super Intendent as the main informant, 1 person supervisor as key informant, and 3 workers as supporting informant . This study was conducted in January-April 2022. The results showed that in the assessment and determination of risk levels were found as many as 20 sources of hazards (hazards) that and cause 22 Accident risks that include 13 risks with low category (Low), 4 risks with category medium (Medium), 5 risks with a high category (High), namely: falling lifting load, overturned lift, hitting workers or other equipment, workers or eqiupment being hit or disturbing other road users, bouncing can injure workers. Recommended to PT.W to pay attention to field activities in each pipe sleeve installation process so that there are no accidents in the field while working.

DEVELOPMENT OF QUALITY ASSURANCE PROGRAM FOR CONSTRUCTION IN OIL AND GAS COMPANY BY USING STATISTICAL QUALITY CONTROL AND SIX SIGMA

Stripe Oil Indonesia operated in Sumatera with a production capacity of 200,000 barrels of oil per day and operated over 530 km of pipelines. Many pipelines have already exceeded their design life with some segments more than 50 years with high potential for leaks that have caused production loss. To extend the operating lifetime of existing pipelines, a pipeline repair project was started in 2019 with sleeve installation. Based on factual data, the project team has experienced a delay in the first 2 months of the project. One of the main contributions to the delay was the welding failure that occurred in January 2019. The welding failure has caused a fire incident due to burn-through in the existing pipeline. The root cause analysis of burn-through incidents has been done with the finding of poor welder performance to meet project requirements. The recommendation is to measure the welder’s performance from heat input data records and analyze the rejection rate and capability index. This research demonstrates how Six Sigma methodology using the DMAIC process and Statistical Quality Control can be applied successfully in pipeline repair projects to address issues of reducing defective welds, improving quality performance, and achieving project milestones. The analysis result showed an improvement in quality performance where the defect rate continued to decline as well as the capability index of the welder continued to improve and completed sleeve installation above the target. The project team also managed to achieve the six sigma level. Improvements also occurred in safety performance which achieved zero incidents due to welding failure (burn-through) from February 2019 to December 2020. In terms of business, actual cost savings achieved 28% from the approved budget.

Failure analysis of various fiberglass cross-arm designs under multi-axial loading

This study investigated the type of failure modes of different cross-arm designs under multi-axial static loading. The failure modes were numerically predicted from real-scale finite-element models of cross-arm integrated with a Hashin damage subroutine. Three finite-element models of cross-arm were considered; a model with standard cross-arm design, a standard design engaged with braces, and a standard design engaged with sleeves. The failure analysis of the composite cross-arm was focused on the location and type of failure of the structure upon its application. This investigation revealed that under the applied load, the cross-arm with installed sleeves exhibited the lowest total deflection of 0.21 m. Every cross-arm design exhibited fiber failure due to the tension and compression mode, regardless of the support system installed. Additionally, the installation of sleeves and braces on the cross-arm structure successfully reduced the number of areas associated to failure.

Numerical Study of Composite Fiberglass Cross Arms under Statics Loading and Improvement with Sleeve Installation

In this paper, the structural deformation of fiberglass composite cross arms under statics loading were numerically simulated using the ANSYS software. The alternate variant of cross arms with one-meter sleeve span installed on both arms was considered as an improvement study. By comparing both cross arms systems, it is found that the total deformation was reduced from 127.49 mm to 95.367 mm by introducing the sleeve. Besides, the stress level appears to be lowered in the cross arms with sleeve installed. The sleeve is regards as a viable solution to reduce both deformation and stress level of cross arms, thus lengthen its life span and saving maintenance costs.

Experimental and numerical investigation of flow forces in a seat valve using a damping sleeve with orifices

The power of hydraulic piston engines is much affected by the on-off valves which control the fuel injection of the piston assembly. Therefore, the opening time of the seat valve used as the on-off valve is optimized by minimizing the axial flow forces on the spool. A damping sleeve with orifices is proposed to change the valve internal geometry. Experimental and numerical investigations of the flow forces acting on the spool with and without the proposed damping sleeve are carried out to identify the differences in the flow field and to minimize the forces’ effect. The simulated results fit the experimental results well. Both results show that the proposed damping sleeve affects the pressure distribution along the spool cone surface and the jet stream direction significantly. The effects of the orifice’s width, height, and relative sleeve installation positions on the flow field and cavitation are assessed using simulation methods. As a result of the flow field changing, the damping sleeve can reduce the flow forces significantly and even reverse the forces’ direction at the cost of a little flow loss. The opening time of the seat valve can be reduced by 31% to 0.67 ms by using the proposed damping sleeve.

Optimization of Pipe Repair Sleeve Design

For the repair of pipeline defects, repair sleeves are the most widely used method in petrochemical industry. The objective of this work was to optimize the thickness of nonpressure containing repair sleeve, by refining the existing design practice. Laboratory studies involving instrumentation of small-scaled repair sleeve system coupled with finite element analysis were carried out to refine the design procedure and optimize the thickness of the sleeve. Using a unified approach for finite element modeling, including failure pressure estimation and simulation of sleeve installation pressure, 24 cases ranging from 6 to 60 in. nominal diameter were investigated. In this paper, the details of the optimization approach used in this investigation are presented.