Fiberglass Rods Research Articles

Impact of damaged housing on the performance of field aged composite High Voltage Insulators

Composite High Voltage Insulators (HVIs) are lightweight, inexpensive, and offer superior pollution performance. Consequently, they have replaced ceramic HVIs in highly contaminating coastal and desert regions. However, they are prone to degradation in harsh environments. In this paper, we assess the performance of three identical field-aged 380 kV composite HVIs with a service life of twelve years near the western coastal region of the Kingdom of Saudi Arabia. The housing of all the HVIs showed widespread damage, including cracks on sheds and shanks, partially or fully broken sheds, and rusted end fittings. The changes in morphology and material composition were assessed through SEM and EDX. An electrical breakdown test in the presence of steam fog revealed lowered withstand strength. Electric field distribution, a key design criterion for an HVI, was studied using the Finite Element Model (FEM) of the insulator bearing physical defects. The results reveal localized electric field intensification caused by all types of defects, notably smaller and narrower ones. Our findings indicate that while physical defects in HVIs can cause localized electric field intensification, they are not a significant concern unless accompanied by severe hydrophobicity loss, compromised electrical withstand levels, or extensive erosion exposing the fiberglass rod and jeopardizing mechanical stability.

Evaluation of an experimental kelp farm’s structural behavior using regression modelling and response amplitude operators derived from in situ measurements

An experimental kelp farming system for exposed ocean conditions was designed, deployed, planted with kelp and instrumented for evaluation of its dynamic response to ocean waves, tides, and currents. The farm featured a novel “lattice” mooring design and anchor lines and cultivation lines (horizontal lines used as kelp growth substrate) made of fiberglass rods. The farm was deployed at a site in Saco Bay, Maine with 13 m (MLLW) water depth. There the farm was exposed to waves with heights up to 5.9 m. Anchor line tension, tide and wave height time series were gathered and processed into response amplitude operators (RAOs) and least squared error linear regression models enabling recognition of meaningful patterns between the forcing factors and the mooring response. Mean mooring line tensions were shown to increase nonlinearly with tide. Anchor line tension response amplitudes were shown to exhibit high sensitivity to both low and high frequency wave forcing. Numerical free-release test simulations suggested natural frequencies in heave of 0.91 Hz, indicating that tension response sensitivities at high frequency could be the result of resonance. Low frequency tension response disproportionate to the low frequency wave forcing could be explained by wave forcing on kelp cultivation arrays modulated by wave group envelopes. Instances of high magnitude, potentially damaging peak tensions, deemed shock loads, were prevalent in most load cases. Anchor line tension dynamics including RAO and shock load magnitudes were shown to be sensitive to mooring stiffness (ratio of tension to resulting elongation) and, in some cases, significant wave amplitude. Patterns of anchor line response indicated that additional mooring elasticity or geometric compliance and use of floatation with less sensitivity to high frequency waves could help avoid the cause of and costly consequences of amplified high frequency loading and high amplitude shock loading. RAOs and regression model results also indicated a subdued response in frequencies associated with ocean swell waves, suggesting desirable performance in waves most dominant in extreme storm events. With the proposed improvements, the farm system design suggests merit as a robust and durable macroalgae biomass production platform.

Design, deployment, and operation of an experimental offshore seaweed cultivation structure

Seaweed cultivation systems suitable for offshore and exposed locations have the potential to enable expansion of global seaweed production to levels capable of substantially supplementing or offsetting terrestrial agriculture. A demonstration scale, experimental seaweed cultivation system (farm) intended to withstand exposed ocean environments was designed, deployed, planted with kelp (a type of seaweed), monitored and decommissioned. Objectives for the field program included: [1] observation of the farm’s behavior and survivability in exposed ocean conditions, [2] demonstration of novel farm system design features and component technologies, and [3] evaluation of farm operability. Novel design features included a lattice mooring system geometry, multi-shaft helical anchors, and the use of fiberglass rod as a replacement for rope anchor lines and kelp growth substrate in order to mitigate the risk of marine animal entanglement. New hardware was developed for transmitting tension loads to and from fiberglass rods, enabling their use in the farm. A numerical model was used in the design stage to simulate the farm in ocean conditions. Analysis results were used to specify farm components, evaluate sensitivities to installation precision, identify potential issues with component interaction, consider operational constraints and investigate the implications of single point failures. The farm was installed at a Gulf of Maine, USA site and planted with Saccharina latissima (sugar kelp) in November 2021 through January 2022 and monitored for one growth season. Kelp was sampled 3 times and met-ocean conditions were measured throughout the season. Kelp was harvested in May 2022 and the structure was removed June 2022. Recovered components were inspected for wear. The farm survived a series of storm events with significant wave heights greater than 2 m and at least one storm with a maximum wave height of 5.9 m. The farm system experienced only minor corrosion, wear and damage. Farm operations revealed the need for improved accessibility, tension control and anchor placement accuracy. Observations and tests revealed relatively poor kelp holdfast attachment to the fiberglass rope replacement. Nonetheless, demonstration results suggest that the experimental farming system design was suitable for use in exposed settings.

Application of fiberglass pipes in geothermal circulation systems

The results of calculating the coefficient of thermal conductivity of the developed construction of the pipeline from multilayer composite spatially oriented fiberglass are given. A method of calculating the coefficient of thermal conductivity of a pipe wall with a complex structure of reinforcement has been developed. The fiberglass pipe is made by the continuous method of oblique-layer longitudinal-transverse winding on a self-feeding frame of reinforcing pseudo-tape moistened with a binder in the form of a rarefied mesh. With each rotation of the mandrel, it shifts by the amount of hardening of the obtained two-component material under the influence of temperature. A comparison of calculated and experimental data was made. When comparing various known calculated dependencies and experimental values, the accepted physical model and the real structure of the material are determined. The known dependences obtained for a medium with infinite long parallel cylindrical inclusions for unidirectional and orthogonally reinforced materials and therefore for materials with a complex structure and scheme of reinforcements give errors and deviations. The work assumes that fiberglass consists of two components - a reinforcing filler and a binder with pores, the reinforcing fibers are endless and have a circular cross-section, the reinforcing fibers are evenly distributed in the matrix of the binder, there is an ideal thermal contact at the boundaries of the distribution between the reinforcement and the binder. Experimental data on determining the transverse thermal conductivity of unidirectional fiberglass rods with reinforcement based on aluminoborosilicate or magnesium-aluminosilicate glass and epoxy binders showed the smallest error in comparison with the calculated ones (8-10%). They investigated the fact that the coefficient of thermal conductivity of a fiberglass pipe is 100 times lower than that of a steel pipe. It was determined that it is possible to replace a steel pipe with a diameter of 219 mm with a fiberglass pipe with a diameter of 146 mm.

Analysis of design and structural features of the external insulation materials of high-voltage devices

In the article, the authors have analysed the design and structural features of various materials for external insulation of high-voltage apparatuses, namely, high-voltage equipment of stations and substations. The operational reliability of the external insulation is determined mainly by the electrical load, which is characterized by the local values of the field strength. The field strength along the insulating cover is distributed very unevenly and has a maximum value near the electrode with high voltage. Electrical isolators are used in all high-voltage apparatus of electrical transmission and distribution circuits to separate the voltage from the ground. The materials used in the development and production of electrical insulators have certain unique characteristics. These materials prevent the free passage of internal electric charges in the material, which makes it practically impossible to conduct an electric current. The ability of a material to prevent electrical conductivity is characterized by its dielectric strength. Polymer insulators allow you to combine high mechanical strength with satisfactory electrical characteristics. In such combined structures, fiberglass rods or cylinders are used as an element that withstands mechanical load. Also, the design of the internal insulation of the capacitor type, impregnated and filled with hardened epoxy resin, allows for particularly precise winding of the synthetic material and the placement of aluminium foils, which provide the capacitive levelling of the graduation and are necessary for the control and formation of the electric field. Such a field is controlled in such a way as to optimize the dimensions, mass and electrical characteristics of the high-voltage apparatus depending on the voltage class and other parameters. The protective polymer coating provides high electrical characteristics of insulators under operating conditions. It is known that during the operation of the high-voltage device, the aging rate of the external insulation is additionally enhanced due to the complex and heterogeneous structure of the insulating cover itself, as well as the influence of the surrounding environment and weather conditions. The main element of external insulation is the supporting insulating cover, in the middle of which the elements of the active part of a certain electrical device are placed. Its basis is usually a glass-epoxy cylinder (this ensures the mechanical stability of the structure), on which ribs made of organosilicon rubber are placed, which in turn ensures the electrical strength of the external insulation.

Study of non-metallic reinforcement influence on the characteristics of cement concrete beam samples properties

The article presents the results of a study of the strength characteristics of beams reinforced with non-matel rods. Tests were performed on concrete samples reinforced with composite and metal reinforcement of different diameters. Based on the results of the study, the tensile strength in bending and the modulus of elasticity of beams with composite reinforcement were determined. Graphs of the dependence of the beam deflections on the load are constructed based on the results of testing concrete samples reinforced with metal and polymer reinforcement. A comparative analysis of the work of metal and polymer reinforcement in concrete was carried out using the example of a rod with a diameter of 8 mm, which indicated higher strength characteristics of composite reinforcement. In turn, the tensile strength in bending of samples with composite and steel reinforcement, respectively, with a diameter of 8 mm and 10 mm has adjacent values. This allows in practice to use composite reinforcement with a smaller cross section.
 The corresponding work of reinforced concrete samples was modeled in the Lira-SAPR software package. The simulation results showed that the reduced deflection of beams reinforced with composite rods at a load of 30 kN, 40 kN has an average deviation of -22%. At the same time, the reduced deflection of samples reinforced with metal rods has a higher convergence with the experimental values and a discrepancy within 10%. Thus, the modeling of the operation of beams with composite reinforcement in software systems requires clarification, or the introduction of additional coefficients in the calculations.
 The results of testing samples of beams and analysis of the properties of non-metallic reinforcement make it possible to prepare proposals for the use of a new type of reinforcement and engineering calculation of cement concrete structures reinforced with fiberglass rods.

THE ACTION OF STRESSES AND DYNAMIC LOADS ON RODS FROM FIBERGLASS, WHEN CATCHING THEM BY THE BODY, WITH A ROD CATCHER

The article discusses the process of gripping the working surface of the spiral, the parts of the rod catcher by the outer surface of the body of fiberglass rods. A diagram of this capture is shown. The diagram shows the forces acting on the gripping surface, between the fiberglass rods and the inner surface of the helix. The greater roughness of the outer surface of the fiberglass rods contributes to their more efficient grip. The drawbacks are indicated in the capture and release of fiberglass rods, which, when designing these rods, are taken into account in the preparation of technical specifications. Keywords: fiberglass rods, deep pumps, tool, workpiece.

Intra-Canopy Sensing Using Multi-Rotor sUAS: A New Approach for Crop Stress Detection and Diagnosis

HighlightsA novel platform was developed for intra-canopy insertion of sensors from a multi-rotor sUAS.The system enables real-time data acquisition from inside the crop canopy comparable to an in-person view.The system provides ideal data for use in modern CNN-based stress diagnosis in row crop production.Abstract. Remote sensing is a critical tool in precision agriculture, giving producers the ability to monitor field conditions throughout the growing season. Although several remote sensing platforms are in use today, small unmanned aerial systems (sUAS) provide the greatest flexibility with the highest resolution. As sUAS capabilities continue to increase (i.e., payload, flight time, and speed), their potential in commercial row crop production is substantial. However, like other forms of remote sensing, traditional sUAS are limited to a nadir view of the target and only capture the top of the crop canopy. Although disease epidemiology and stress origins vary, this limited view usually does not capture the impact of stress at the initial manifestation. For example, stresses such as macronutrient deficiencies in corn originate at the base of the plant and then move upward as nutrients translocate. By the time the stress is detectable at the top of the canopy, the opportunity to mitigate yield loss is limited. A new sUAS platform is needed for sensing beneath the upper portion of the canopy. The Stinger platform, developed to meet this need, consists of a 4.0 m fiberglass rod, custom sensor mount, communication network, and radio link. Using this platform, a variety of sensors can be inserted into the crop canopy from a hovering sUAS. The Stinger platform, when combined with artificial intelligence (AI), significantly expands the capabilities of sUAS for diagnosis of crop stress in row crop production. Keywords: Intra-canopy sensing, Remote sensing, RGB imagery, Stress diagnosis, sUAS.

Effect of Non-Metallic Composite Reinforcement on Load-Bearing Capacity

It is known that non-metallic composite reinforcement was invented in the 60's of the last century, and already then, a large number of scientists began to investigate its physical and mechanical characteristics. Despite its rather old age, this reinforcement has not been sufficiently studied for its work in building structures. Fiberglass composite reinforcement (Arvit) is a high quality construction material with many advantages: 4-5 times less weight compared to metal of the same diameter; it does not rust or oxidize; tensile strength is 2 times higher than metal reinforcement; it does not conduct electricity; high resistance to temperature changes from -70 to +200 ° C; easy to transport. The distinctive features of work of fiberglass composite reinforcement in bending spacer elements are still insufficiently studied, which in design and production practices leads to the non-use of such reinforcement in the construction of elements of buildings and structures. The experimental results of the test specimens are presented in the article. In first test specimen, longitudinal working reinforcement was made of two metal rods Ø8 class A400S, in second - two fiberglass rods Ø8 AKS 600.

Experimental and numerical investigation of fiberglass rod joint on mechanical characteristic and failure mode in high water-content wells

ABSTRACT At present, fiberglass sucker rod has been gradually utilized in low permeability reservoirs because of their high strength and strong corrosion resistance. However, the bonding joint of fiberglass sucker rod in high water-content well is particularly prone to break and fall off, which influences the service life and construction safety of recovery operation. Current researches mainly focused on the bonding strength at room temperature, and less consideration was given to the residual strength and failure pattern under immersion. This paper proposed a novel diffusion-structure finite element model (FEM) based on transient dynamic method to simulate the process of water into the joint, and the life-death element method was adopted to study the progressive damage of bonding joints verified by indoor experiment in order to predict residual failure strength and obtain failure mode in submerged environment. As immersion duration extended, the results illustrated that a) the cohesive failure gradually became main failure; b) the maximum von Mises stress, shear stress, and end deformation of bonded joint increased and the maximum interfacial stress barely unchanged within the range of 5%; c) the numerically predicted strength decreased from 21.8 to 11.5 MPa, which was in good agreement with the experimental results within a deviation of 8%.

Оптимизация технологического режима работы установок скважинных штанговых насосов с комбинированной стеклопластиковой штанговой колонной

Оптимизация технологического режима работы установок скважинных штанговых насосов с комбинированной стеклопластиковой штанговой колонной

An improved high-precision Jacob's staff with laser sighting and topographic capabilities for the high-resolution stratigrapher

ABSTRACT Accurate and quick high-resolution measurements of stratigraphic thicknesses and geologic profiles exposed in surface outcrops are critically important for interpreting depositional environments, basin development, and tectonic evolution. Therefore, a high-precision instrument is required for high-resolution stratigraphic measurements. Herein, a new version of the Jacob's staff incorporating an Abney level or a geological compass, a laser pointer, and a handheld GPS is presented. Both the Abney level and the laser pointer are oppositely positioned side by side at the 1.5 m position on the 1.6-m-long fiberglass rod, and they can synchronously slide vertically and rotate horizontally. Because accurate sighting of bedding surfaces is facilitated with both the sighting tube of the Abney level and straight-line beam of the laser pointer, this novel design greatly improves the precision and speed of stratigraphic thickness measurements. More importantly, when the section requires a lateral shift, the straight-line beam can easily and precisely identify the new start point without rotating the rod, which greatly reduces potential changes in the angle of the rod. The GPS unit installed at the top of the rod synchronously records the track of the measured section and coordinates of each measurement, which enables acquisition of a topographic profile along the stratigraphic section. Uncertainties in stratigraphic thickness measurements are minimized when observations are made through the sight tube of the Abney level when the rod is oriented perpendicular to the bedding surface.

About structural elements of polymer insulators of the contact network

The high load on electrified lines makes tougher the requirements for the reliability and maintainability of power supply devices. Insulators are a critical element of the overhead contact network, and great attention is paid to improving their characteristics — electrical and mechanical strength. Advantages of polymer insulators in comparison with traditional ones made of porcelain and glass are generally recognized: manufacturability, low weight, compactness, ease of installation and transportation, high mechanical strength and shock resistance.The article presents the results of comprehensive studies of the electrophysical characteristics of fiberglass rods and bars made of AG-4S carried out by the University of Railway Engineers (MIIT), which were used in the developed polymer structures of the contact network. Recommendations are given on the maintenance of fiberglass rods and bars from AG-4S and their engineering support. The issues of the mechanical strength of polymer insulators of the overhead contact network are covered quite fully, therefore, this article offers the basic principles for calculating their electrical strength. The main requirements for modern polymer insulators and design features are briefly presented for each type: suspended, tension, cantilever, fixing and supporting.

Tests features of composite materials under complex mechanical loads

The article presents the results of the analysis of existing standardized and scientifically based methods for studying composite materials under quasistatic, low-velocity impacts and cyclic loadings in conditions of normal, high and low temperatures. Based on a review of existing test methods, research methods have been developed and tested to study the changes in the strength and deformation properties of GFRP composite materials under complex mechanical loads. A new type of interpretation of experimental data in the form of diagrams of fatigue and low-velocity impact sensitivity is proposed. Characteristic sections and points are introduced on the diagrams, which make it possible to further use the data from the diagram for the design of products and structures made of composite materials operated under the conditions of unforeseen external mechanical influences. For all developed methods, the results of experimental studies conducted by the authors of the work are presented. As an example, an experimental study of the influence of additional torsional vibrations on the processes of deformation and fracture of unidirectional fiberglass rod samples under quasistatic tension is considered.

Transmissibility of coffee fruit-peduncle-branch systems submitted to vibration induced by impact

The development of efficient machines for coffee harvesting requires solid knowledge about the dynamic behavior of the plant. Vibration transmissibility is a parameter on dynamic behavior that may help understand this process. The aim of this study was to evaluate the average vibration transmissibility in coffee fruit-peduncle-branch samples containing unripe and ripe fruits. The experiments were performed using Arabica coffee plants of the cultivar Catuaí Vermelho. The samples were submitted to three vibration frequency levels, 20, 30 and 40 Hz, induced to the branch with impact of rigid fiberglass rods moving at a constant amplitude 2 mm. Data on acceleration were collected using an accelerometer fixed to the branch. The frequency of 20 Hz presented the highest transmissibility. Samples containing ripe fruits also presented high transmissibility when compared to those containing unripe fruits.

Development of an adjustable safety lock with glass and plastic rods used for a reversable plow

The article deals with a design of the adjustable lightweight safety device made from composite materials and used for reversible plows. Initially, a design scheme was developed. It was theoretically and experimentally investigated. Research was conducted by the Department of Tractors and Agricultural Machines of the Gorsky State Agrarian University. As a result, software was developed. It is used to determine rational values of the main parameters of the safety lock. The following values of the parameters were obtained: the diameter of fiberglass rods dr = 16 mm; the rod length lr = 0.85 m; the number of rods nr = 16 (8 in each spring); the height of the center of the stop e = 0.15 m; the radius of the crank rr = 0.12 m; the rod length lr = 0.25 m; the initial value of the angle of crank rotation acro = 30 … 700. During the laboratory experimental studies, using the strain gauging method, we studied a change in the traction resistance of a section when it is deepened, and reliability of obstacles of various heights. The traction resistance was 7800 … 11600N, which is sufficient to ensure reliable operation of the plow section in the North Caucasus region. In all experiments, a decrease in the traction resistance was observed when the section returned after deepening to its original position, which was caused by the gravity section and hysteresis losses in the composite rods. Field tests of the upgraded model of the reversible plow PON-3 confirmed high efficiency of the safety lock design.

Numerical Solutions and Experimental Research in Justification of the Design Model of the Force Interaction of the Reinforcing Beam with the Anchoring Medium

The paper presents the research and engineering experience in the calculation and design of concrete structural elements, reinforced by fiberglass rods. The construction of a concrete beam reinforced by fiberglass rods is presented. Research in preserving prestressing forces in a beam subjected to weathering for about 30 years is considered. The creation and analysis of concrete-steel connection model is presented using LIRA-SAPR software. This is a work of scholarly interest.

A novel method of output metering with dynamometer card for SRPS under fault conditions

Remote monitoring of sucker rod pumping system (SRPS) based on polished rod dynamometer cards (DC) is an effective means to reduce the operating costs and realize the real-time control. Nevertheless, how to obtain the working process and the production rate of SRPS from polished rod DC is always a puzzle because of complex down-hole motions. The typical solution for this problem is deriving the pump DC via the wave equation to achieve the effective stroke of plunger. But some key parameters involved in this approach such as valve leakage and the fill factor are difficult to determine accurately, especially under fault conditions, which may influence the accuracy of output metering.In order to address this tough issue, in this paper, a novel method of output metering with DC is proposed based on quantitative analysis of fault. The method consists of two parts, the first part is an approach to simulate the working process of SRPS under fault conditions, specifically it's an improved simulation model characterized by a set of fault parameters, which is presented through analyzing the mechanisms of sucker rod pumps at normal and several faulty scenarios. And the second part is a method implemented by genetic optimization algorithm to determine the fault parameters set of the actual SRPS.Using parameters of typical well, the analysis of effects of faults on SRPS is carried out. The simulation results show that valves leakage reduces the flow rate of liquid significantly in the period of effective stroke, which leads to the distortion of output metering results of effective stroke method. Compared with single faults, coupling faults aggravate the production reduction of SRPS. Furthermore, when the well fluid contains gas, the impact of traveling valve leakage on the reduction of production is greater than that of standing valve leakage, but the consequence is opposite when formation energy is insufficient. Besides, the carbon fiber rod and fiberglass rod SRPS are more sensitive to valve leakage, while the steel rod and wire rope SRPS are more sensitive to the condition of insufficient liquid supply.Eventually, the proposed method is verified experimentally through the productive parameters and measured DC of actual wells collected from an oilfield. The obtained results demonstrate the effectiveness of the proposed method for output metering and fault diagnosis as well.

Effect of the impact of rigid rods on coffee fruit detachment efficiency by mechanical vibrations

The mechanization of field activities has been the response of coffee producers to the labor shortage, especially for fruit harvesting. The use of mechanical harvesters allows greater harvesting efficiency and ensures the economic viability of coffee plantations, which currently depend mainly on the reduction in production costs. The principle used for mechanized coffee harvesting is based on the principle of mechanical vibration. The objective of this studywas to analyze the dynamic behavior of the coffee fruit-peduncle-branch system under mechanical vibration and the impact of the vibrating rods on the fruit detachment process in association with this behavior. Fragments of coffee branches containing fruits in the unripe and ripe stages were used in this experiment. These samples were subjected to different frequencies (20, 30, 40, and 50 Hz) and amplitudes (0.002, 0.003, and 0.004 m). Another variableanalyzed was the form of vibration transmission to the fruits, with the vibrations being transmitted to the samples with or without the impact of the fiberglass rods. The fruit detachment efficiency increased as the ripening stage progressed from unripe to ripe. A higher detachment efficiency occurred with the increase in vibration frequency and amplitude because of the higher vibrational energy imposed on the fruit. The detachment efficiency was low when the vibration was transmitted without the impact of the rods. Conversely, the vibration in combination with impact achieved a mean detachment efficiency of approximately 90%.Key words: Coffee crop; dynamic behavior; harvester machine; mechanical harvesting.

Joint Work of Cement Concrete and Composite Reinforcement with Periodic Profile Winding

A study of the joint work of cement concrete and material winding fiberglass composite reinforcement with different types of coatings and types of windings was conducted. The type of periodic profile winding is presented, which increases the adhesion of the material of glass fiber reinforcement winding with cement concrete. It has been established that the winding of the periodic profile improves the strength properties of the composite reinforcement material. The influence of aggressive media on the adhesion of fiberglass rods with different types of surface preparation from cement concrete is estimated.