Hose Failure Research Articles

ДОСЛІДЖЕННЯ НЕСПРАВНОСТЕЙ ГІДРАВЛІЧНИХ РУКАВІВ ПРИ ЕКСПЛУАТАЦІЇ ВИЛОЧНИХ НАВАНТАЖУВАЧІВ В МОРСЬКИХ ПОРТАХ

This study focuses on hydraulic hoses utilized in the hydraulic systems of forklifts. The investigation examined 8 forklifts, each with a loading capacity of 10 tons. The check took place every six months over a three-year span. Before and after each shift, the forklift operator performed visual checks and hydraulic system and brake а inspections. The research findings indicated that the most frequent hose malfunction was a result of a rupture. The failure rate noticeably increased during the winter, attributable to the low temperatures' adverse effect on the hoses' physical and mechanical properties. Another common area of hydraulic hose failure is due to substandard crimping and minimal fitting depth in the sleeves..

Effect of ion penetration on the aging of EPDM components used in caustic liquid transfer lines by microscopic analysis

Effect of ion penetration on the aging of EPDM components used in caustic liquid transfer lines by microscopic analysis

LANDING GEAR FAILURES CONNECTED WITH HIGH-PRESSURE HOSES AND ANALYSIS OF TRENDS IN AIRCRAFT TECHNICAL PROBLEMS

Reliability and maintenance analysis in aviation industry focused on a main objective of the accident and incident investigations what are help to better understand the causes of accidents. In the article suggested the underlying concept by scorecard of situations what lead to aviation accidents. In the present research, the aviation accident connected with a landing gear and a problem of failure to follow maintenance instructions during a maintenance on aircraft landing gear hydraulic drive was under an investigation, on an example of root cause analysis of the failure of hydraulic flexible highpressure hoses. The approach presented in this research of experimental measurements, based on fluid pressure measuring, high-pressure hoses vibration measuring and frequency’s analysis. By spectrum analyses was found that high-pressure hoses are most susceptible to deformation at frequencies to the response of the fluid within, as well as at hoses material resonance frequencies. The compact version of hoses is more deformational on the resonance points than a standard version of hose. In final according to analyses, was established that disrespect of the frequency conditions was leaded to causes irreversible degradation changes of the hose inner structure and occurrence of material defects inside layers contact what lead in final step to hose failure.

Uncertainties in failure rates in the LNG bunkering risk assessment

The increasing use of Liquefied Natural Gas (LNG) in shipping has led to an increased interest in marine bunkering safety in ports. The main tool for risk management and siting of bunkering facilities is quantitative risk assessment. This paper addresses the uncertainties in the available data on bunker equipment (loading and unloading arms and hoses), safety system failure rates, and ignition probabilities required for risk assessment. Using the search engines Scopus and Google, a literature search was conducted for studies and papers on the risk assessment of LPG bunkering. Analysis of the relevant studies revealed that different sources of data were used for equipment failure rates and ignition probabilities. The analysis of failure rates for leaks and ruptures of arms and hoses revealed that there are several problems with comparability, but also that there is a high degree of uncertainty, with data ranging from two to four orders of magnitude. The analysis of ignition probabilities showed that the uncertainty is about two orders of magnitude for small releases and within one order of magnitude for large releases. The failure rates of the emergency shutdown systems are within one order of magnitude. A wide range of arm and hose failure rates represents a large uncertainty for a reliable risk assessment. The way forward appears to be a transparent data collection system that describes the scope and the various assumptions.

High-pressure hydrogen decompression in sulfur crosslinked elastomers

High-pressure storage and cyclic (de)pressurization of hydrogen gas is known to result in degradation and failure of gas canisters, hoses, linings, and O-rings as the relatively small hydrogen molecule can readily permeate most materials. Hence, identifying material compositions that are less susceptible to hydrogen-induced damage is of significant importance to the hydrogen energy infrastructure. Here, we use classical atomistic molecular dynamics simulations to study hydrogen exposed ethylene-propylene-diene monomer (EPDM) rubber, an elastomer typically used in O-rings. We make chemical modifications to the model by adjusting the crosslink density and report on gas solubility, diffusivity, and molecular restructuring in response to rapid decompression. Our simulations indicate that increases in crosslink density can reduce volumetric expansion during decompression and result in smaller free volume pore sizes. However, these favorable properties for sealing materials come with a tradeoff. At pressure, crosslinks introduce extra free volume, providing potential sites for gas localization, the precursor to cavitation-induced failure.

Quantitative Risk Assessment for Aerospace Facility According to Windrose

Wind direction and speed are the most important factors that determine the degree of damage caused by a jet fire. In this study, the metal hose used to extract/supply fuel was identified as the component with the highest risk for a jet fire occurring at an aerospace facility. A risk assessment was performed to evaluate the individual risk of a jet fire from the metal hose according to the wind direction and speed. HSE failure data was applied for calculating the jet fire probability including metal hose failure, ignition frequency, and jet fire frequency. Which was 3.0 × 10−4. The individual risk of different fatality probabilities was calculated according to the wind rose data for the aerospace facility. The individual risk from jet fire in the aerospace facility was calculated with a maximum risk of 3.35 × 10−5 and a minimum risk of 1.49 × 10−6. The individual risk satisfied HSE ALARP criteria. In addition, firewalls, extinguishing systems, and an emergency shut off system were enhanced, and it was thought that the risk from jet fire could satisfy acceptable criteria.

Experimental and numerical study on explosion characteristics and hazards of methane-air mixtures in a chamber

ABSTRACT The high-frequency failure of hoses inside residential kitchens is easy to cause natural gas explosion accidents. A small-scale gas explosion experiment platform like a kitchen was constructed in this work. Three sets of explosion experiments for methane-air mixtures with 7.7%, 9.5%, and 11.2% were performed, respectively, and the explosion venting characteristics were analyzed. The influence of vent area ratio, vent opening pressure, and mass per unit area of pressure relief panels on the explosion hazards (i.e., explosion overpressure, flame temperature, dynamic pressure, explosion wind velocity, and combustion rate) were investigated using CFD simulations. Meanwhile, the accuracy of numerical model was validated against experimental data. The results show that the maximum peak overpressure at 9.5% could reach up to 5.55 kPa, whereas that was 2.34 kPa at 7.7% and 5.09 kPa at 11.2%. The numerical model with thermal radiation effect could reproduce the experimental results effectively. The vent area ratio and vent opening pressure have great influence on the external damage distances, whereas there is little effect of mass per unit area. The secondary injuries caused by flame temperature, dynamic pressure, explosion wind velocity, and combustion rate outside the buildings except explosion overpressure should be also paid special attention in a gas explosion accident.

The Combined Effect of High Temperature and Ethylene Glycol (EG) on Polyethylene Terephthalate (PET)-Reinforced Coolant Hose Failure in Combustion Engines

Cooling systems in internal combustion engines can be based on liquid, air, or a combination of both. This study presents two cases of cooling system failure in a four-stroke internal combustion engine cooled by a combination air and liquid cooling system with ethylene glycol as coolant. The coolant elastomer hoses in these engines are made of PET-reinforced silicone rubber braid. The decline in mechanical performance of such elastomer hoses following exposure to extreme temperature and certain liquids is a known phenomenon. In this study, the effect of environmental conditions on hose tensile strength was examined using fractography, and analytical and mechanical tests under various ambient conditions and different combinations of oil, air, and coolant. Engine temperature was tracked in several locations in the engine. The signs of hose failure were exhibited as changes in color, swelling, fiber separation, or disintegration. Engine temperature measurements showed that the failure occurred in highest temperature location. It also indicated that the high temperature is a result of the proximity to the exhaust manifold which is located directly below the coolant hose. This study demonstrates for the first time that the exposure to a high temperature and to ethylene glycol as a combination is a critical factor in compromising the mechanical properties of PET-reinforced silicone rubber. Moreover, it is destructive than exposure to either high temperature or ethylene glycol separately. In fact, this study shows that combined exposure to ethylene glycol and a high aging temperature (200 °C) caused a decrease of a 79% in tensile strength and a 61% decrease was noticed as a result of exposure to high temperature and air. Designers of engine cooling systems and similar applications can utilize the results of this study when deciding on cooling system location, type of thermal insulation, coolant liquid, and hoses material.

New method for monitoring the residual life of high pressure hoses

The presented method is designed to monitoring the residual life of hydraulic drive elements. In this work, as an element of the hydraulic drive, high-pressure hoses are used, which are used in hydraulic drives of technological equipment of transport and technological machines. As a diagnostic parameter that characterizes the technical condition of the high-pressure hose, the frequency of natural oscillations of the pipeline with the liquid is adopted. Experimentally, the dependence of the natural oscillation frequency of the high-pressure hose on the dynamic loading cycles of the harmonic type was obtained, which were used to determine the probability of failure of pipelines and to find a strategy for their replacement. The probability of failure of high-pressure hoses for different periods of operation is determined on the basis of the obtained experimental dependences of the natural vibration frequency of pipelines on their operating time. Using the obtained dependences of the probability of failure of high-pressure hoses, it is possible to determine the possible residual life of pipelines and the need for their replacement. This method can be used to determine the probability of failure of other elements of the hydraulic drive, such as hydraulic cylinders, hydraulic valves, pumps, and others.

A study on the causes of the destruction of the high pressure hoses during operation and cyclic tests

High pressure hose (HPH) is a flexible pipeline for the transportation of special hydraulic and motor fluids based on mineral oil, liquid fuel, grease or water emulsion under pressure, to transfer the working force. Structurally, the sleeve is two or more rubber tubes placed one into the other, reinforced with metal braids or coils, equipped with connecting fittings [1]. HPH is characterized by a sufficiently high flexibility in combination with the ability to withstand significant pressure.In cases of premature failure of high-pressure hoses during cyclic or impulse tests, the cause of the nonconformity must be determined. The article describes the main stages of the study of defective high-pressure hoses in determining the cause of their failure and provides examples of studies using visual, metallographic, electron microscopic methods of analysis in the metallographic laboratory of OJSC «BSW – Management Company of Holding «BMC».

Mechanical Assessment of Fuel Line Hoses under Variable Pressure

The automotive industry is one of the largest consumer of flexible hoses for fluids such as fuel or cooling. In order to limit the post production costs, every aspect of a vehicle must be tested in advance, including the lifespan, durability or failure of hoses. Throughout this paper summary results are presented for 4 types of fuel line hoses tested under controlled displacement loads at various pressures in order to validate the Finite Element Method simulations.

Investigation on structural behavior of ring-stiffened composite offshore rubber hose under internal pressure

Abstract Ring-stiffened composite offshore rubber hose of single carcass is commonly used for offshore oil transfer. Common hose dimensions are length of 10.7 m and nominal diameter of 500 mm. The nominal burst pressure is 7.5 MPa, equal to five times rated working pressure of 1.5 MPa. The hose carcass is composite cylindrical tube made of rubber, reinforcing fiber cords and steel spiral stiffener that provides radial stiffness. In hose design, the burst pressure shall be determined to verify its pressure bearing capacity. In this paper, a nonlinear finite element hose model is created with commercial software ABAQUS and validated to predict its structural behavior under internal pressure. The large deformations, interactions between components and nonlinear material properties of hyperelastic rubber and fibers are considered. Stresses of stiffener, radial and axial deformation and load in reinforcement plies are obtained. A bulging phenomenon amid two stiffeners is found, which indicates the confine effect of stiffeners. Failure pressure is jointly determined by the strength limit of polymer cords and steel stiffener. The influence of different fibers and rubbers on hose pressure-deformation response are compared. The results demonstrate good accordance with requirement of specification. The finite element model can predict hose failure pressure and provide guidance for reliable hose design in practice.

Simulation Study on the Potential of Braided Hose Failure in Internal Combustion Engines

In this study, damaged braided hoses was obtained from the actual site to investigate the possible causes of failure in the internal combustion engines. The hoses were assembled with polytetrafluroethylene (PTFE) as the inner tube and externally braided outer tube corrosionresistant steel (CRES). The hose had undergone failures near the end of the fittings. The braided hose was measured and modelled using SOLIDWORKS CAD software. The ANSYS static structural stimulation was used to measure the stress distribution on the hose due to pressure applied with various bend shapes. The simulation was done by fixing the end of the pipe and exerting the working pressure inside the inner layer of PTFE. The results of the simulation have shown that the inner tube experienced high stresses near the fittings which is then aggravated with the bending. With cyclic pressure loading, the hose was unable to stand the high stresses near the fittings and therefore failed. Further analyses were done to the braided hose to investigate the other possible of failure using failure analysis method.

Design of a Fast Measuring System for the Section Size of Automobile Rubber Hose Withhold Parts

The quality of withhold parts determines the service life of high-pressure rubber hose to a great extent. Leakage at withholding is the main form of high pressure hose failure in the several forms. The quickest and most effective method to detect the withholding quality is measuring the section size of the withhold parts. As long as the section size is in line with the provisions, that is, the quality of hose withholding is qualified. In this paper, the mesurement system which is designed improves low efficiency of manual mesurement.

Fire, water and everyday life: Bushfire and household defence in a changing climate

This paper examines how the availability or scarcity of water influenced the survival related decisions of households during the October 2013 State Mine Fire in the Blue Mountains, New South Wales, Australia. Narrative analysis of semi-structured interviews with 18 households impacted by the bushfire revealed that drought conditions in the months preceding the bushfire left many households dependent on non-reticulated water supplies vulnerable at the time the fire threat became apparent. Despite considerable preparations for water storage and usage during the fire, “weak links” in planning (e.g., top-ups, failure of pumps, generators and hoses) meant water was not accessible when needed most. This paper discusses a gap in bushfire safety scholarship on water usage and everyday trade-offs amongst residents in areas independent of reticulated (mains) water supplies. Findings suggest a need for more detailed and consistent information in official bushfire safety advice on storing water prior to a bushfire and effective water distribution systems for household defence and fire fighting.

Chlorine transfer hose failure

On the morning of 14 August 2002, a 1 in. transfer hose used in a rail tank car unloading operation at DPC Enterprises, near Festus, Missouri, catastrophically ruptured and initiated a sequence of events that led to the release of 48,000 pounds of chlorine--a toxic gas--into neighboring areas. The facility repackages bulk dry liquid chlorine into 1 ton containers and 150 pound cylinders for commercial, industrial, and municipal use in the St. Louis metropolitan area. Fortunately, the wind direction on the day of the release limited the effects of the chlorine plume on the surrounding community. However, 63 people sought hospital treatment due to exposure, and hundreds of others were affected by the release (the community was advised to shelter-in-place for 4 h, and traffic was halted on Interstate 55 for 1.5 h). The US Chemical Safety and Hazard Investigation Board (CSB) investigated this incident for the following reasons: This paper presents the lesson-learned from this incident to help prevent similar occurrences. This paper is based on US Chemical Safety and Hazard Investigation Board Report Number 2002-04-I-MO, which was approved by the Board on 1 May 2003. This paper has not been independently approved by the Board and is published for general informational purposes only. Every effort has been made to accurately present the contents of the Board-approved report in this paper. Any material in the paper that did not originate in the Board-approved report is solely the responsibility of the author and does not represent an official finding, conclusion, or position of the Board. A complete copy of the Board investigation report upon which this paper is based is available on the CSB website at "Completed Investigations."

Hydraulic hose failures caused by corrosion of the reinforcing strands

Hydraulic hose failures are quite often catastrophic events that impact the safety of the work environment. This presentation outlines an insidious cause of hose failure—the early warning signs of which may often go undetected until failure occurs—corrosion. Three separate unrelated failures are illustrated, all of which resulted in serious safety incidents. Corrosion of the reinforcing wire strands was found to be the primary cause of all three hose failures. A number of factors are identified for consideration and discussed, including cause(s) of the corrosion, methods of detection of corrosion damage, design issues, and maintenance strategies.

The NRDA Process can be Timely and Productive for All

ABSTRACT On August 24, 1998, there was an accidental hose failure at Tesoro Hawaii Corporation's (“Tesoro Hawaii” or “Tesoro”) single-point mooring (SPM) about a half mile off Barbers Point, near Honolulu, Oahu, Hawaii. The incident released approximately 117 barrels of bunker fuel. Immediate containment and clean up efforts were commenced, but on September 5, 1998, tarballs began to come ashore on Kauai. Shoreline impacts were observed between Kilauea Point to Makahuena Point on the eastern shore and between Makaha Point and Mana Point on the western shore of Kauai. To avoid the costs and delays associated with litigating resource damages that may have resulted from the release and any associated civil penalties, the Trustees and Tesoro Hawaii entered into a cooperative Natural Resource Damage Assessment (NRDA) protocol. The Trustees and Tesoro Hawaii conducted a phased approach focusing on injury determination and quantification using technical working groups (TWGs) composed of Trustee and Tesoro Hawaii representatives. Resource injuries considered were for seabirds, marine environment (opihi), marine mammals (Hawaiian monk seal), and human use. To expedite the process, it was agreed that time and money would best be spent identifying and scaling restoration projects. Coordination of effort was key to cost-effectiveness of the assessment and avoiding duplication of studies. The Final Restoration Plan and Environmental Assessment were accomplished within two years, including public participation. Restoration actions were undertaken promptly following execution of the Consent Decree. One of the initiatives developed by this collaborative effort was a derelict net removal project (the “Project”). The Project met the goals of the Trustees by compensating for interim losses to shoreline, intertidal and subtidal habitats and the biota in those habitats and by addressing potential injury to the endangered Hawaiian monk seal.

Mechanism of Failure in Women's Hosiery

Analysis of failure in women's hosiery reveals that hose durability is strongly related to the amount of stretch in the hose as well as to yarn strength. Although snagging is the major cause of hose failure, only about 1% of the total snags result in failure because the snagging force is usually removed or reduced prior to yarn breakage. At equivalent yarn breaking strength, hose from stretch yarns are more durable than nonstretch hose because longer snags develop and reduce the probability of the snagged yarn exceeding its breaking strength. Long snags occur when the hosiery structure collapses easily and there is low resistance to yarn withdrawal. A high propensity for snagging, irrespective of snag length, does not necessarily result in poor durability and evidence is presented to show this. The analysis of the above mechanism of failure is supported by wear test data with both stretch and conventional hose.

'Rubber Acid' Damage in Fire Hoses

IN a brief reference, Crosby, Fiske and Forster1 mention that a common cause of hose failure in rubber-lined fire hoses may be due to sulphuric acid formed from sulphur present in hoses when these are not properly dried. Such damage, apparently, was almost unknown in Great Britain before the War, but has recently been much in evidence. According to Phillips2, 'rubber acid' is produced, and its damage observed chiefly in fire stations which lack adequate draining and drying facilities. It would appear to affect primarily, if not exclusively, rubber-lined fire hose.