Evaluation of Pipeline Impact Damage

2012 ◽  
Author(s):  
Hagbart S. Alsos ◽  
Ragnar T. Igland ◽  
Tore H. Søreide
Keyword(s):  
Kinetic Energy ◽  
Impact Damage ◽  
Third Party ◽  
Dissipated Energy ◽  
Element Analysis ◽  
Cross Sectional ◽  
Pipeline Design ◽  
The Impact ◽  
Impact Experiments ◽  
Engineering Protection

The safety of pipelines and subsea structures are key elements in subsea field developments. As part of the safety engineering, protection from dropped objects and third party impact actions is required. This article addresses this aspect. The combined response from global deflection and denting of pipelines subjected to impacts is investigated. Analysis and testing methods applied in pipeline design are presented. Focus is placed on the overall interaction between the impacting object, the deformed pipeline and energy dissipation by soil. Typically, pipeline damage from design codes provides conservative cross sectional damage estimates. This is confirmed from both simplified and detailed FE analyses, as well as impact experiments performed by REINERTSEN AS. One of the main objectives promoted by the authors is the importance of impact velocity and mass during impact, and not only the kinetic energy of the impact. The kinetic energy from a dropped object is unlikely to be fully dissipated as cross sectional deformation of the pipeline. Global deformations will be triggered, which implies that the dissipated energy going into local denting is reduced to a fractional value. This paper discusses the impact mechanics and seeks to estimate the fractional value by using simplified element analysis.

Advanced Pipeline Impact Design

2016 ◽  
Author(s):  
Ragnar T. Igland ◽  
Hagbart S. Alsos ◽  
Stig Olav Kvarme
Keyword(s):  
Energy Dissipation ◽  
Kinetic Energy ◽  
Impact Velocity ◽  
Large Diameter ◽  
Small Diameter ◽  
Energy Estimates ◽  
Dissipated Energy ◽  
Accurate Information ◽  
Cross Sectional ◽  
The Impact

The safety of pipelines and subsea structures are key elements in subsea field developments. As part of the safety engineering, protection from dropped objects and third party impact actions is required. This article addresses this aspect. Dropped object from a platform or a vessel is one of the design scenarios. The fall-pattern of the object is essential for the impact velocity and corresponding energy, model of the path and the effects of hydrodynamic behavior is outlined. In lieu of accurate information, the design code use energy band for energy estimates and may give extremely conservative impact energy. The falling objects structural flexibility and properties are discussed and evaluated regarding the energy dissipation and possible damage of the pipeline. The pipeline combined response from global deflection and denting regarding impacts are investigated. Analysis and testing methods applied in pipeline design are presented. Focus is placed on the overall interaction between the impacting object, the deformed pipeline and energy dissipation by coating and soil. Typically, pipeline damage from design codes provides conservative cross sectional damage estimates. This is confirmed from both simplified and detailed FE analyses, as well as fullscale impact experiments performed by REINERTSEN AS. One of the main objectives promoted by the authors is the importance of both impact velocity and mass during impact, and not only the kinetic energy of the impact. The kinetic energy from a dropped object is unlikely to be fully dissipated as cross sectional deformation of the pipeline. Global deformations will be triggered, which implies that the dissipated energy going into local denting is reduced to a fractional value. The effect is more pronounced for small diameter pipelines than for pipelines with large diameter. This paper discusses the impact mechanics and seeks to estimate the fractional value by using simplified element analysis.

What Is the Impact of Prior Authorization on the Incidence of Pediatric Tonsillectomy?

2020 ◽  
pp. 019459982096963
Author(s):  
Vanessa F. Torrecillas ◽  
Kaden Neuberger ◽  
Alexander Ramirez ◽  
Paul Krakovitz ◽  
Jeremy D. Meier
Keyword(s):  
Elective Surgery ◽  
Lag Time ◽  
Cross Sectional Study ◽  
Health Claims ◽  
Third Party ◽  
Prior Authorization ◽  
Cross Sectional ◽  
Before And After ◽  
The Mean ◽  
The Impact

Objective Third-party payers advocate for prior authorization (PA) to reduce overutilization of health care resources. The impact of PA in elective surgery is understudied, especially in cases where evidence-based clinical practice guidelines define operative candidacy. The objective of this study is to investigate the impact of PA on the incidence of pediatric tonsillectomy. Study Design Cross-sectional study. Setting Health claims database from a third-party payer. Methods Any pediatric patient who had evaluation for tonsillectomy from 2016 to 2019 was eligible for inclusion. A time series analysis was used to evaluate the change in incidence of tonsillectomy before and after PA. Lag time from consultation to surgery before and after PA was compared with segmented regression. Results A total of 10,047 tonsillectomy claims met inclusion and exclusion criteria. Female patients made up 51% of claims, and the mean age was 7.9 years. Just 1.5% of claims were denied after PA implementation. There was no change in the incidence of tonsillectomy for all plan types ( P = .1). Increased lag time from consultation to surgery was noted immediately after PA implementation by 2.38 days (95% CI, 0.23-4.54; P = .030); otherwise, there was no significant change over time ( P = .98). Conclusion A modest number of tonsillectomy claims were denied approval after implementation of PA. The value of PA for pediatric tonsillectomy is questionable, as it did not result in decreased incidence of tonsillectomy in this cohort.

Building resilience in retail supply chains: Lessons learned from COVID-19 and future pathways

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Atif Saleem Butt
Keyword(s):  
Supply Chain ◽  
Supply Chains ◽  
United Arab Emirates ◽  
Cash Flows ◽  
Lessons Learned ◽  
Third Party ◽  
Structured Interviews ◽  
Cross Sectional ◽  
Content Type ◽  
The Impact

PurposeThis study explores the countermeasures taken by retailers to mitigate the effects of COVID-19 on supply chain disruptions.Design/methodology/approachThis research uses a multiple case study approach and undertakes 36 semi-structured interviews with senior management of the four largest retailers of the United Arab Emirates. The respondents were designated at different positions such as Vice President, Director and Project Manager.FindingsResults reveal that retailers are employing six countermeasures to mitigate the effects of COVID-19 on supply chains. Particularly, retailers are securing required demand, preserving cash flows, redirecting inventory, adding capacity to their distribution centres, becoming more flexible with their direct or third-party logistics provider and finally widening delivery options for their suppliers to mitigate the impact of COVID-19.Research limitations/implicationsThis study has some limitations. First, the results of this study cannot be generalized to a broader population as it attempts to build an initial theory. Second, this study uses a cross-sectional approach to explore the countermeasures employed by retailing firms to mitigate the effects of COVID-19.Originality/valueA notable weakness in a supply chain disruption literature is an unfulfilled need for research examining the strategies employed by retailers to respond to/address the challenges posed by COVID-19. Our study fills this gap.

Experimental and simulation investigation on BVID and CAI behaviors of CFRP laminates manufactured by RTM technology

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Fang Chen ◽  
Weixing Yao ◽  
Wen Jiang
Keyword(s):  
Compressive Strength ◽  
Impact Damage ◽  
Projection Area ◽  
Element Analysis ◽  
Mechanical Fracture ◽  
Content Type ◽  
Explicit Finite Element ◽  
Compression Load ◽  
Cfrp Laminates ◽  
The Impact

Purpose The purpose of this paper is to synthetically investigate the impact damage responses of carbon fiber reinforced polymer (CFRP) and its influence on the compression mechanical responses of CFRP laminates, including damage distribution, residual compressive strength and fracture morphology. Design/methodology/approach A progressive damage simulation model is developed to analyze the complicated damage responses of CFRP laminates that are manufactured by resin transfer method (RTM) technology. Based on the ABAQUS/explicit finite element analysis solver, a VUMAT code is proposed to descript the composite materials’ damage behaviors under both impact and compression load. Adopting this proposed model, the primary mechanical indicators of four groups’ 5284RTM/U3160 CFRP laminates with different stacking sequences are predicted. Moreover, impact and compression after impact tests are conducted to verify the accuracy of simulation results. Findings Both simulation and experimental results show that the impact damage with low visible detectability can significantly reduce composites’ compressive strength. For all four groups’ composite laminates, the residual strength ratio is around 35% or even lower. The kernel impact damage near the plates’ geometric center promotes the degradation process of local materials and finally leads to the early occurrence of mechanical fracture. In addition, the impact damage projection area is not sensitive to the parameters of stacking sequences, while the residual compression strength is proportional to the number of 0-degree layers within whole laminates. Originality/value This study helps to understand the effect of an impact event on CFRP laminates’ compressive bearing capacity and provides a numerical method in simulating the damage responses under both impact and compression load.

scholarly journals Freeze-Thaw Cycle Effect on Sputtering Rate of Water-Saturated Yellow Sandstone under Impact Loading

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Yunbing Hu ◽  
Tianzhu Duan ◽  
Penghui Xian ◽  
Liang Chen
Keyword(s):  
Kinetic Energy ◽  
Specific Energy ◽  
Impact Loading ◽  
Freezing Temperature ◽  
Dissipated Energy ◽  
Particle Sizes ◽  
Loading Test ◽  
Freeze Thaw ◽  
Water Saturated ◽  
The Impact

In order to explore the impact of freeze-thaw temperature on the sputtering rate of water-saturated yellow sandstone under impact loading, in this paper, the Hopkinson pressure bar is used to conduct impact loading test on the water-saturated yellow sandstone at the same strain rate (74.22 s−1) under five different freeze-thaw temperatures. After impact loading, the yellow sandstone fragments are graded and screened by using the sizing screen, and the mass of fragments with different particle sizes after screening is counted. By transforming the fragments into spheres with the corresponding particle sizes, and combining the dissipated energy, the surface specific energy of yellow sandstone with different freeze-thaw temperatures is calculated. Finally, the sputtering rate of the fragments is obtained by using the relationship of total work, dissipated energy, and kinetic energy. The main conclusions are as follows: The freeze-thaw temperature has a significant effect on the fracture degree of yellow sandstone. The lower the freeze-thaw temperature is, the higher the fracture degree of yellow sandstone is, and the smaller the particle size distribution of fragments is. The fractal dimension of yellow sandstone increases with the decrease of freeze-thaw temperature, indicating that the damage of yellow sandstone is more serious. The dissipative energy of yellow sandstone increases with the decrease of freezing temperature, while the kinetic energy increases gradually when the freeze-thaw temperature is −30°C to −15°C and decreases gradually when the freeze-thaw temperature is −15°C to −5°C. The surface area and surface specific energy of yellow sandstone fragments both increase with the increase of freeze-thaw temperature. And the sputtering rate of yellow sandstone fragments increases gradually at freezing temperature from −30°C to −15°C and decreases gradually at −15°C to −5°C. Therefore, from the perspective of dynamic destruction process, the sputtering of yellow sandstone fragments at freezing temperatures of −15°C, −20°C, and −30°C is more intense than that at −5°C and −10°C. The results can provide some guidance for production in winter and winter regions.

scholarly journals Effective Formula for Impact Damping Ratio for Simulation of Earthquake-induced Structural Pounding

Geosciences ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 347 ◽  
Author(s):  
Seyed Mohammad Khatami ◽  
Hosein Naderpour ◽  
Rui Carneiro Barros ◽  
Anna Jakubczyk-Gałczyńska ◽  
Robert Jankowski
Keyword(s):  
Kinetic Energy ◽  
Impact Force ◽  
Damping Ratio ◽  
Dissipated Energy ◽  
Force Model ◽  
Single Collision ◽  
Structural Pounding ◽  
Impact Forces ◽  
The Impact ◽  
Impact Damping

Structural pounding during earthquakes may cause substantial damage to colliding structures. The phenomenon is numerically studied using different models of collisions. The aim of the present paper is to propose an effective formula for the impact damping ratio, as a parameter of the impact force model used to study different problems of structural pounding under seismic excitations. Its accuracy has been verified by four various approaches. Firstly, for the case of collisions between two structural elements, the dissipated energy during impact has been compared to the loss of kinetic energy. In the second stage of verifications, the peak impact forces during single collision have been analyzed. Then, the accuracy of different equations have been verified by comparing the impact force time histories for the situation when a concrete ball is dropped on a rigid concrete surface. Finally, pounding between two structures during earthquakes has been studied. The results of the analysis focused on comparison between dissipated and kinetic energy show relatively low errors between calculated and assumed values of the coefficient of restitution when the proposed equation is used. In addition, the results of the comparison between experimentally and numerically determined peak impact forces during single collision confirm the effectiveness of the approach. The same conclusion has been obtained for the whole impact time history for collision between a ball and a rigid surface. Finally, the results of the comparative analysis, conducted for pounding between two structures during an earthquake, confirm the simulation accuracy when the proposed approach is used. The above conclusions indicate that the proposed formula for impact damping ratio, as a parameter of impact force model for simulation of earthquake-induced structural pounding, is very effective and accurate in numerical simulations in the case of different scenarios.

scholarly journals Modeling Analysis of Guided Ultrasonic Waves in Composite Plates with Impact Damage

2018 ◽  
Vol 7 (4.26) ◽  
pp. 175
Author(s):  
Noorfaten Asyikin Ibrahim ◽  
Bibi Intan Suraya Murat
Keyword(s):  
Composite Structures ◽  
Impact Damage ◽  
Composite Plates ◽  
Guided Wave ◽  
Ultrasonic Waves ◽  
Fe Model ◽  
Element Analysis ◽  
Damage Area ◽  
Guided Ultrasonic Waves ◽  
The Impact

This paper investigates the propagation of guided ultrasonic waves and the interaction with impact damage in composite plates using a full three-dimensional Finite Element analysis. Impact damage in the composite plate was modeled as rectangular- and T-shaped delaminations. In order to provide guidelines for extending the modeling of realistic multimode impact damage, the impact damage was modeled as a combination of the delamination and reduced materials properties. The information obtained from these methods was compared to the experimental results around the damage area for a validation. There was a reasonable similarity between the experimental and FE results. The FE simulations can effectively model the scattering characteristics of the A0 mode wave propagation in anisotropic composite plates. This suggests that the simplified and easy-to-implement FE model could be used to represent the complex impact damage in composite plates. This could be useful for the improvement of the FE modeling and performance of guided wave methods for the in-situ NDE of large composite structures. 

scholarly journals Effect of single tube sections on the structural safety of Chinese solar greenhouse skeletons

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xingan Liu ◽  
Zhenkun Li ◽  
Lei Zhang ◽  
Yu Liu ◽  
Yiming Li ◽  
...  
Keyword(s):  
Material Selection ◽  
Selection Process ◽  
Load Condition ◽  
Structural Features ◽  
Structural Safety ◽  
Element Analysis ◽  
Cross Sectional ◽  
Single Tube ◽  
The Impact ◽  
Selection Of

AbstractIn recent years, the use of single-tube skeletons for the construction of Chinese solar greenhouses has increased. As a consequence, during the selection of the construction materials, the safety of these structures has become an important issue. The single tube section has various forms, but there is no scientific theory to guide the selection process. To the best of our knowledge, the scientific analysis of the impact of single pipe cross section on the safety of greenhouse skeleton has not been addressed so far. In this context, the finite element analysis software was used to calculate and analyze the stress elements, displacement of round tube, Ω tube, elliptic tube and square tube under the same load conditions. We used the Chinese Standard values as a reference and analyzed structural features of different sizes and thicknesses of the greenhouse steel skeleton sections under non-uniform snow load. The results showed that, under the same load condition, the maximum stress in the four skeleton materials was all located at the connection of the transverse tension bar and the front roof. In addition, under same load condition, the greenhouse skeleton with elliptic tube presented the smallest cross-sectional displacement between the different materials tested. The effect of increasing the size of the greenhouse frame was better than that of increasing the greenhouse material thickness. All this work will provide theoretical guidance to the material selection of this structure.

Containment and Arrest of Blade Shedding in Gas Turbine Engines Using Novel Dual-Ring Design

2021 ◽  
Author(s):  
Prayers Roy ◽  
Shaker A. Meguid
Keyword(s):  
Energy Absorption ◽  
Impact Damage ◽  
Impact Resistance ◽  
High Energy ◽  
Element Analysis ◽  
Single Ring ◽  
High Energy Absorption ◽  
Interfacial Gap ◽  
The Impact ◽  
Dual Ring

Abstract In this paper, we examine the energy absorption and containment capabilities of a newly proposed dual-ring design accounting for interactions between a released blade and fully bladed fan disk using 3D finite element analysis. The components of this dual-ring design are strategically selected to ensure high energy absorption and high impact resistance, thus leading to reduced damage of the disk and increased safety. Three containment ring designs are examined: (i) conventional single-ring design composed of one of titanium, aluminum or Kevlar, (ii) a newly proposed aluminium-Kevlar dual-ring arrangement, and (iii) dual-ring arrangement with an interfacial gap between them to arrest and contain the released blade and ensure free passage of the trailing blades. The results of our numerical simulations indicate that although the single-ring design resists penetration and contains the released blade within the confines of the disk, it does not remove the released blade from the path of the trailing blades leading to severe damage to the fan disk. On the contrary, our new dual-ring design, which contains an interfacial gap, has potential to successfully arrest the released blade within the confines of the ring and out of the path of the trailing blades. This design significantly can reduce the impact damage to the fan disk and reduces kinetic energy of the released blade to near zero in less than half a rotation of the fan disk.

Design and Analysis of Flywheel for Different Geometries and Materials

2017 ◽  
Vol 9 (1) ◽  
pp. 95 ◽  
Author(s):  
Ankita Shinde ◽  
Kratika Singh Rawat ◽  
Ruchi Mahajan ◽  
Veeraj Pardeshi ◽  
Balbheem Kamanna ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Cross Sections ◽  
Storage Capacity ◽  
Critical Factor ◽  
Project Work ◽  
Jet Engines ◽  
Element Analysis ◽  
Cross Sectional ◽  
Ic Engine ◽  
Design Engineers

Flywheel is a mechanical device used to store energy and utilize it whenever it required. Flywheels find its application in number of fields ranging from IC engine of 2-wheeler to more powerful jet engines. Increase in Kinetic Energy of flywheel is the most critical factor for the design engineers. The literature survey shows that flywheel can be redesign for mass optimization which results light weight and Increase in storage capacity. In this project work, an attempt is made to redesign the existing flywheel in terms of its geometry and different materials. Different cross sections of the flywheel are designed using 3D designing software Solidworks 2015. Finite Element analysis is used to calculate the Maximum Rotational speed the flywheel and the amount of Kinetic energy stored at that speed. The results shows that flywheel with Triangular cross sectional geometry and made of S-glass epoxy composite material stores highest Kinetic Energy per unit mass compare to all other combination of Geometries and materials. This New design of flywheel saves weight by 65.252kg compared to existing designs.

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