Evaluation Of Damage Mechanisms Research Articles

Inspection and evaluation of damage mechanisms in two-phase vertical separator

Pressure vessels are critical components in various industries that store or transport fluids under pressure. Ensuring their mechanical integrity prevents catastrophic failures and maintains safe and reliable operations, regular inspections are necessary to identify potential defects and damages that can compromise the vessel's integrity. However, practical guidelines for pressure vessel inspection are often not readily available in educational institutions and require specialized certification courses or on-field experience. This article aims to provide a comprehensive and practical approach to inspecting a two-phase vertical separator commonly used in oil and gas based on industry standards and codes, specifically targeting mechanical engineers, engineering students, and professionals entering the inspection field. It demonstrates the application of a standardized methodology for inspecting a pressure vessel and analyzing its damage mechanisms. The inspection standards applied in this study include API-510, API-571, API-572, API-579, and API-580. The inspection process encompasses both external and internal evaluations. External inspections focus on identifying conditions that may affect the mechanical integrity of the vessel, such as support structures, corrosion, or external damage. Internal inspections utilize visual and non-destructive testing (NDT) techniques to detect damage or discontinuities within the vessel. It includes inspection planning, component selection, thickness measurements, and NDT techniques. The external inspection findings include thickness measurements of the shell, nozzle, and coupling areas. The identified material loss percentages are compared to design limits, enabling the determination of remaining structural integrity and the need for repairs or further evaluations.

Tension-after-impact analysis and damage mechanism evaluation in laminated composites using AE monitoring

The present paper focuses on the detection of dominant damage mechanisms in tensile loading of laminated composite specimens subjected to low-velocity impact (LVI) using acoustic emission (AE) method. Moreover, the effects of various nanoparticles (NPs) on the tension-after-impact (TAI) strength of glass fiber-reinforced polymer (GFRP) composites have been investigated. The hierarchical method was employed to cluster the acoustic emission data and detect the damage mechanisms of the composites. These damage are matrix cracking, fiber–matrix debonding, fiber breakage, and fiber pull-out, the peak frequency ranges of which were obtained to be (100–200), (250–370), (410–530), and (570–650) kHz, respectively. Subsequently, the existence of these mechanisms was verified using Scanning Electron Microscope (SEM) images, and their shares in composite failure under tensile loading were calculated by wavelet transform method. According to the results, the NPs have enhanced the impact strength of the GFRPs by up to 66% reduction in damage index. Furthermore, they have increased TAI strength by up to 39%, claims also supported by the AE analysis.

Numerical analysis of 3D dry-stone masonry structures by combined finite-discrete element method

The evaluation of damage mechanism and the failure of dry-stone masonry structures subjected to seismic load is one of the most important aspects of seismic assessment of existing masonry buildings. Discontinuities between the blocks, their mechanical interaction, large displacement and rotation are the main causes of degradation and collapse of these structures. This paper presents the application of the combined finite-discrete element method (FDEM) in the analysis of 3D dry-stone masonry structures which is able to capture such mechanisms and structural damage both at joint and at block level. Moreover, the proposed approach includes friction forces based on Coulomb-type of law accounting for friction effects across dry joints and open cracks, in order to correctly simulate the mechanical behaviour of dry-stone masonry. The capabilities of presented approach are demonstrated in a series of numerical tests, starting with sliding and rocking of single blocks, examination of dry joints shear behaviour, walls subjected to in-plane and out-of-plane load, and finally the simulation of the simple spatial stone masonry structure.

Technology Focus: Formation Damage (February 2017)

Technology Focus In a corresponding article from 2015, I quoted the title of Brant Bennion’s 1999 article “Formation Damage—The Impairment of the Invisible, by the Inevitable and Uncontrollable, Resulting in an Indeterminate Reduction of the Unquantifiable.” I would like to think that, given the considerable effort spent on drilling- and completion-fluid development since the article was written, we have a much better control of the “inevitable and uncontrollable.” Likewise, with respect to a “reduction in the unquantifiable,” much of the uncertainty can be minimized by performing representative corefloods using plugs of different permeability value to reflect the values expected downhole. It is permeability that is often the most difficult to quantify; therefore, focusing on permeabilities in coreflooding to cover the span of those likely to be encountered can improve our understanding of the potential formation damage that could be expected. In this short article, I would like to focus on “the impairment of the invisible” because it is here that the greatest uncertainty exists with regard to formation-damage evaluation. One of the challenges for those involved with understanding an unexpected decline in well performance is identifying the exact causes for the reduced productivity because we cannot see downhole what type of damage has occurred and where. Production engineers can use significant amounts of time in attempting to identify a cause for poor productivity. This process involves evaluating all that has happened in the well, which includes the fluids used, losses during drilling and completion, lower-completion type and potential for plugging, and how effective well cleanup was. Consideration of all data available can eventually point toward one factor that could explain productivity decline. Core-flooding can also be used to simulate the sequences performed in the well, to try to identify the damaging mechanism. Regardless of those factors, the key take-home message is that prevention is much better than cure. Recommended additional reading at OnePetro: www.onepetro.org. SPE 178963 Laboratory Simulation and Damage in Openhole Water Injectors by Michael Byrne, LR Senergy, et al. SPE 178018 Evaluation of Damage Mechanisms in Tight Gas Reservoirs: Field Example From Perth Basin by Nick Bahrami, SGS Netherlands, et al. SPE 179007 Ability of a Filter-Cake Breaker To Diffuse Into Completion Brine and Packed Gravel by Clotaire-Marie Eyaa Allogo, Schlumberger, et al.

Classification of acoustic emission signals collected during tensile tests on unidirectional ultra high molecular weight polypropylene fiber reinforced epoxy composites using principal component analysis

The objective of this study is to utilize a mathematical procedure for the evaluation of damage mechanism in ultra high molecular weight polypropylene/epoxy composite (UHMWPP/epoxy) specimen with different configuration based on the analysis of the AE signals of presented. Principal component analysis (PCA) is powerful tool, which utilized for the classification of the monitored AE transients. We worked on epoxy L160 resin, UHMWPP fiber bundle and UHMWPP/epoxy unidirectional specimens, subjected to tensile loading. Using model specimens exhibiting a predominant damage mechanism, correlations were established between the observed damage growth mechanisms and the AE parameter variances result in PCA. Outputs from this study revealed that the PCA is an effective tool for identifying damage modes such as matrix cracking, fibre/matrix debonding, fibre breakage and fibre pull-out in the UHMWPP/epoxy composites. The presence of damage modes in UHMWPP/epoxy composites was proven with scanning electron microscopy (SEM) images.

Evaluation of damage mechanisms and skin factor in tight gas reservoirs

Tight gas reservoirs normally have production problems due to very low matrix permeability and significant damage during well drilling, completion, stimulation and production. Therefore, they may not flow gas at optimum rates without advanced production improvement techniques. The main damage mechanisms and the factors that have significant influence on total skin factor in tight gas reservoirs include: mechanical damage to formation rock; plugging of natural fractures by mud solid particle invasion; relative permeability reduction around wellbore as a result of filtrate invasion; liquid leak-off into the formation during fracturing operations; water blocking; skin due to wellbore breakouts; and the damage associated with perforation. Drilling and fracturing fluids invasion mostly occurs through natural fractures and may also lead to serious permeability reduction in the rock matrix that surrounds the natural or hydraulic fractures. This study represents an evaluation of different damage mechanisms in tight gas formations, and examines the factors that can have significant influence on total skin factor and well productivity. Reservoir simulation was carried out based on a typical West Australian tight gas reservoir to understand how well productivity is affected by each of the damage mechanisms, such as natural fracture plugging, mud filtrate invasion, water blocking and perforation. Furthermore, some damage prevention and productivity improvement techniques are proposed, which can help improve well productivity in tight gas reservoirs.

502 単結晶シリコンウエハ主要面の引掻き試験による表面損傷機構の評価(切削・研削・研磨加工I)

502 単結晶シリコンウエハ主要面の引掻き試験による表面損傷機構の評価(切削・研削・研磨加工I)

Non-Destructive Evaluation of Damage Mechanisms in Composite Sandwich Structure

This paper presents the experimental results obtained of flexurally loaded wind turbine blade cross section material. All material was extracted from a wind turbine blade box girder and testing was conducted in four point configuration. The aim was to gain an understanding of the structural integrity of this lightweight material as it deforms in flexure. To allow for thorough analysis, digital image correlation (DIC) was used to produce full field strain maps of the deforming specimens. Results highlight the capability of the DIC technique to identify regions of failure, as well as the aspects responsible for them. Overall, the results present a foundation for tests on larger substructure, and eventually integration into manufacturing and maintenance aspects of the industry.