Risk Of Structural Failure Research Articles

Health-Monitoring Systems for Marine Structures: A Review.

This paper presents a comprehensive review of the state-of-the-art developments in health monitoring of marine structures. Monitoring the health of marine structures plays a key role in reducing the risk of structural failure. The authors establish the different sensors with their theoretical foundations and applications in order to determine the optimal position of the sensors on board. Once the data were collected, it was necessary to use for subsequent treatment; thus, the authors identified the different methodologies related to the treatment of data collected by the sensors. The authors provide a historical review of the location of different sensors depending on the type of ship and offshore platform. Finally, this review paper states the conclusions and future trends of this technology.

Risk-Based Integrity Management System of Oil Tanker Hull Structure due to Corrosion

The ship hull construction suffers a decrease in strength performance over its life cycle due to corrosion and fatigue. Therefore, the risk of structural failure also rises during the extended service life if maintenance is not performed properly. The budget, on the other hand, limits these activities. As a result, it is critical for ship owners to plan an optimal maintenance program. The idea of this research is to find the best way to keep the hull's structural integrity due to corrosion. A time dependent corrosion model has been developed for failure prediction purposes, based on the historical data of plate thickness reduction. Failure scenarios are carried out on local, global and fatigue strength. This research adopted a semi-quantitative risk assessment along with reliability analysis to give strategic maintenance planning by lowering the risks that would be encountered. Hence, ensuring uninterrupted service of the ship throughout the service life. Finally, this study will be very useful as reference to establish risk informed program to evaluate the risk level of components of hull that guides to adjust inspection intervals without avoiding safety requirements.

An innovative method of assessing yield strength of floater hull for semi-submersible floating wind turbine in whole life period

The concepts of external and internal corrosion damage of materials have been proposed, and the improved corrosion damage models considering marine corrosion zone have been established. Then, a new method of assessing yield strength of floater hull for semi-submersible floating wind turbine considering the effect of corrosion damage in whole life period is proposed based on the equivalent design wave and structural quasi-static analysis method. Taking the OC4 floating wind turbine foundation for example, this new assessment method has been conducted. The results show that the stresses and displacements of structures will be increased under the influence of corrosion damage in whole life period and the risk of structural failure is also increased due to the corrosion damage. The structures which locate in the high stress level region will up to the yield failure critical point (yield strength margin is close to zero) by the end of service period if just considering the external corrosion damage, and these structures may fail due to yield after 18–22 years of service if considering the external and internal corrosion damage simultaneously. Therefore, the corrosion damages (especially the internal corrosion damage) have produced an important effect on the structural yield strength. In addition, the value of material factor γm = 1.1 (given by DNVGL-ST-0119) is small, and the suggested value is 1.25–1.3 for the structures in high stress level region.

Analisis getaran lambung kapal patroli 28 meter

The ship's vibration is something that has a considerable influence on the structural resistance and comfort of the crew. Vibration analysis needs to be done to ensure the durability of the ship's construction. Ship construction that is unable to withstand the vibrations it experiences is at great risk of structural failure. Vibration on the ship is also something that can only be suppressed and cannot be completely eliminated. The objectives to be achieved in this final project are to get the value of the ship's resistance and get the root-mean-square value of the maximum vibration speed that occurs on the ship. The calculation of the value of the ship's resistance is carried out using the Holtrop resistance calculation method, while the determination of the root-mean-square maximum speed of vibration is carried out using the Ansys Workbench. The resistance value obtained on this ship is 7,165 kN. The root-mean-square value of the greatest maximum vibration velocity occurs at a frequency of 47.2 Hz at 76.71906943 m/s. Due to the limit value of r.m.s for aluminum vessels is 15 mm/s, then the value of r.m.s at a frequency of 47.2 Hz that occurs on ships does not meet class standards.

A Quantitative Method for Assessing and Monetizing the Failure Risk of Prefabricated Building Structures under Seismic Effect

As a new construction mode, the prefabricated building is the main direction of the transformation and upgrading process of the Chinese construction industry. In an earthquake area, prefabricated building damage is often reported; therefore, it is important to evaluate the failure risk of its structure under seismic effect. In this paper, combined with the vulnerability and building depreciation theory of prefabricated buildings, as well as a seismic hazard analysis of engineering sites, we propose a quantitative method for evaluating the structural failure risk of prefabricated buildings under seismic effect during their service life. In order to illustrate the proposed method, a residential prefabricated building as described in the previous study is used as a case study. The structural failure risk value and overall risk level of the case under seismic effect are calculated to verify the feasibility and effectiveness of the seismic risk evaluation method. The results demonstrate that the proposed method benefits and assists risk management in the decision making and disaster prevention and mitigation regarding prefabricated buildings.

Electrochemical behavior and corrosion rate prediction study of alloy 690

Alloy 690 is a material commonly used in heat transfer tubes of steam generators (SGTs). The electrochemical corrosion behavior in different volumes (V) of NaCl–Na2S2O3 solution for different surface roughness (Ra) of alloy 690 was studied, and a BPNN model for predicting electrochemical corrosion parameters of alloy 690 was established (CP and CCD). The results show that Ra on the surface of alloy 690 destroys the passivation film and changes the oxygen vacancies in the passivation film, so that Cl− is more easily attached to the passivation film. Finally, accelerated electrochemical reactions on the surface of SGTs. When the solution is Na2S2O3, with the increase of Ra on the metal surface (0.0977≤ Ra ≤ 1.1661), the corrosion potential gradually decreases. BPNN can accurately predict the electrochemical corrosion rate of alloy 690 under different conditions, and the relative error is less than 10%. In this paper, an artificial intelligence model is established for the first time to predict the relationship between Ra and electrochemical corrosion, and the conclusion can be used to schedule the maintenance process of the SG, thereby reducing the risk of structural failure and maintenance costs.

Damage detection in simply supported beams using machine learning

The more our infrastructure is aging, the risk of structural failure is higher, making the detection of damage using modal parameters a very important factor that can be applied in structural health moni-toring. The most desired way to assess the health of engineering structures during operation is to use non-destructive vibration-based methods. In the current paper, a modal approach using a machine learning technique by training a feedforward backpropa-gation neural network for detecting transverse damages in simple supported beam-like structures is presented. A method for analyti-cal determination of the training data is used and the obtained da-taset values are employed for training an ANN that will be used to locate and evaluate the severity of transverse cracks in cantilever beams. The output from the ANN model is compared by plotting the calculated error for each case in comparison with FEM results us-ing the SolidWorks simulation software.

First Principles‐Based Approach for 3D Scour Processes Under Variable Jet Discharge

AbstractScour processes caused by plunging jets are particularly important in hydraulic engineering because of the connected risk of structural failure. Therefore, many investigations have been conducted on this topic, focusing on jet‐induced scour under constant flow discharge (i.e., steady case). Yet, to the best of the authors' knowledge, no studies have analyzed the scour mechanism under variable jet discharge (i.e., unsteady case) and clear‐water conditions. Following recent theoretical advancements on scour phenomena for steady cases based on the phenomenological theory of turbulence, we address in this study the general validity of such an approach for time‐dependent (i.e., unsteady) jet inflow conditions, in non‐cohesive soils. Results show that scour evolution is consistent with that obtained for steady jet flows. In particular, they confirm the existence of two distinct phases—developing and developed—and indicate that the transition time between the two phases does not depend on the jet inflow characteristics. Once again, this study confirms that the phenomenological theory of turbulence is a valid tool for all jet‐driven scour problems.

Structural Ultimate Strength Analysis of Anti-Collision Facility of Yinzhou lake Bridge Under Vessel-Generated waves

Under the condition of complex waters, the long-term action of a vessel-generated wave makes the anti-collision facilities have the risk of structural failure. Taking the Yinzhou lake bridge pier anti-collision structure as the research object, the extreme vessel-generated wave load is calculated, and the structural strength of the floating anti-collision facility under the action of the vessel-generated wave is analyzed using the direct calculation method. The results indicate that the ultimate strength of the overall structure of the anti-collision facilities meets the design requirements, but there is insufficient strength in some parts. A strengthening scheme to meet the design requirements of structural yield strength is proposed.

Strain measurements of an aircraft wing using embedded CNT fiber sensor and wireless SHM sensor node

Composite material-based aircraft structures have attracted attention due to their lightweight and superior mechanical properties. However, composite structures have a high risk of structural failures when damages occur due to loadings or impacts. Therefore, consistent structural health monitoring (SHM) is needed to ensure the structural integrity and safety of the aircraft. Various methods of sensor installation and measurement systems were developed for the implementation of SHM in aircraft structures. In this research, the carbon nanotube (CNT) fiber sensor was optimized by comparing the different configurations such as carbon black concentration, polyurethane layer, and dip-coating iterations. Glass fiber reinforced plastic skin with embedded CNT fiber sensor was implemented on a 1700 mm long right main wing. Strain measurements were performed during static loadings through the wireless SHM sensor node. Strain measurement due to resistance change during temperature decrease was also performed to investigate the effect of temperature on the CNT fiber sensor. The CNT fiber sensor showed comparable strain measurement results to conventional strain gauge strain measurements. Consequently, the CNT fiber sensor and the wireless SHM sensor node showed new possibilities for embedded sensor applications and real-time SHM implementations for aircraft structures.

Hollow mandibles: Structural adaptation to high-speed and powerful strike in the trap-jaw ant Odontomachus monticola

The trap-jaw ant Odontomachus monticola manipulates its hollow mandibles to generate extremely high speed to impact various objects through a catapult mechanism, making the violent collision occur between the mandible and the impacted objects, which increases the risk of structural failure. However, how the ant balances the trade-off between the powerful clamping and impact resistance by using this hollow structure remains elusive. In this combined experimental and theoretical investigation, we revealed that the hollowness ratio of the mandible plays an essential role in counterbalancing the trade-off. Micro-CT and high-speed images suggested that the hollow mandibles facilitate a high angular acceleration to 108 rad/s2 for an enormous clamping force. However, this hollowness might challenge the structural strength while collision occurs. We found that under the same actuating energy, the von Mises stress of the object collided by the natural mandible striking can reach up to 2.9 times that generated by the entirely solid mandible. We defined the efficiency ratio of the von Mises stress on the impacted object to that on the mandible and found the hollow mandible achieves a more robust balance between powerful clamping and impact resistance compared to the solid mandible.

Selection Of Profiles In Midship Vessel Structure Operating The Regulations Of The Indonesian Classification Bureau

Ship construction generally consists of two main parts: the hull and the superstructure or deck house. Several factors must be considered in the construction of a ship. Planning the characteristics of the ship's hull, we are also planning the strength and structure of the ship itself. Midship construction is a construction that must have serious attention in calculating the ship structure. In this section, many forces are acting so that there is a relatively large risk of structural failure. One of the world's classification institutions is BKI, which provides rules for selecting structural profiles. Based on these rules, the load on ship sides is 71,284 KN/m2. Load on the ship bottom is 76,795 KN/m2, Deck Load on Deck Superstructures is 32,581 KN/m2, Load on Cargo Deck is 57,330 KN/m2, Load on Inner Bottom is 68,212 KN/m2, Load on Accommodation Decks is 3,981 KN/ m2.

Selection Of Profiles In Midship Vessel Structure Operating The Regulations Of The Indonesian Classification Bureau

Ship construction generally consists of two main parts: the hull and the superstructure or deck house. Several factors must be considered in the construction of a ship. Planning the characteristics of the ship's hull, we are also planning the strength and structure of the ship itself. Midship construction is a construction that must have serious attention in calculating the ship structure. In this section, many forces are acting so that there is a relatively large risk of structural failure. One of the world's classification institutions is BKI, which provides rules for selecting structural profiles. Based on these rules, the load on ship sides is 71,284 KN/m2. Load on the ship bottom is 76,795 KN/m2, Deck Load on Deck Superstructures is 32,581 KN/m2, Load on Cargo Deck is 57,330 KN/m2, Load on Inner Bottom is 68,212 KN/m2, Load on Accommodation Decks is 3,981 KN/ m2.

STRUCTURAL RESPONSE AND DAMAGE EVALUATION OF A TYPICAL HIGHRISE RC BUILDING IN DUBAI UNDER AN EARTHQUAKE WITH SINGLE AND MULTIPLE PEAKS

Seismic design codes predominantly assume that earthquakes involve a single ground shaking event; however, earthquakes can occur as a series of shocks. Consequently, the capacity of structures to resist earthquakes with multiple peaks without suffering severe damage is a crucial parameter. This research study evaluates the seismic performance of a high-rise building in Dubai using existing records of single and multiple peaks. Three-dimensional building model was developed considering the actual cross-sections of the horizontal and vertical elements fitting the seismic zone through dynamic response spectrum analysis. The building is analyzed using the nonlinear regime employing fast-nonlinear timehistory analysis with the scaled NS and EW records of the Niigata earthquake. The main finding of this work is that records with multiple peaks significantly increase structural response and magnify the structural damage compared with records of single-peak earthquakes; thus, earthquakes involving multiple shocks significantly increase the risk of structural failure in a building.

Convolutional Neural Networks for Automated Built Infrastructure Detection in the Arctic Using Sub-Meter Spatial Resolution Satellite Imagery

Rapid global warming is catalyzing widespread permafrost degradation in the Arctic, leading to destructive land-surface subsidence that destabilizes and deforms the ground. Consequently, human-built infrastructure constructed upon permafrost is currently at major risk of structural failure. Risk assessment frameworks that attempt to study this issue assume that precise information on the location and extent of infrastructure is known. However, complete, high-quality, uniform geospatial datasets of built infrastructure that are readily available for such scientific studies are lacking. While imagery-enabled mapping can fill this knowledge gap, the small size of individual structures and vast geographical extent of the Arctic necessitate large volumes of very high spatial resolution remote sensing imagery. Transforming this ‘big’ imagery data into ‘science-ready’ information demands highly automated image analysis pipelines driven by advanced computer vision algorithms. Despite this, previous fine resolution studies have been limited to manual digitization of features on locally confined scales. Therefore, this exploratory study serves as the first investigation into fully automated analysis of sub-meter spatial resolution satellite imagery for automated detection of Arctic built infrastructure. We tasked the U-Net, a deep learning-based semantic segmentation model, with classifying different infrastructure types (residential, commercial, public, and industrial buildings, as well as roads) from commercial satellite imagery of Utqiagvik and Prudhoe Bay, Alaska. We also conducted a systematic experiment to understand how image augmentation can impact model performance when labeled training data is limited. When optimal augmentation methods were applied, the U-Net achieved an average F1 score of 0.83. Overall, our experimental findings show that the U-Net-based workflow is a promising method for automated Arctic built infrastructure detection that, combined with existing optimized workflows, such as MAPLE, could be expanded to map a multitude of infrastructure types spanning the pan-Arctic.

Effects of different management measures on soil conservation and the influence of environmental conditions: a case study involving UAV remote sensing on the Loess Plateau

AbstractTo curb further deterioration due to soil erosion, the Chinese government has successively implemented a series of ecological improvement projects across the Loess Plateau (LP). This study used unmanned aerial vehicle remote sensing combined with the revised universal soil loss equation to quantitatively evaluate the soil conservation rate (SR) under 10 management measures and further incorporated the topographic slope into the analysis to describe the impacts of terrain changes. The results showed that the average SR of plots under artificial management measures was 61.24 ± 0.004% (P < 0.01), whereas that under non‐artificial measures was 47.90 ± 0.007% (P < 0.01), which showed that human activities on the LP beneficially improved the SR. In addition, benefiting from the Grain to Green Project, cultivated fields, and economic forests exist only in areas with gentle slopes, and both these areas experience almost no threat of soil loss. A terraced structure exerts an obvious effect on extremely steep slopes (>40°), and a greater slope is associated with a more evident effect. However, the risk of structural failure also increases. In addition, due to restricted water conditions, the effects of existing soil and water conservation measures that use tree planting as the main method have the characteristics of horizontal and vertical zonation differentiation. Valley bottom and semi‐humid areas are more profitable, and other areas are more suitable for planting drought‐tolerant shrubs. In addition to guiding the deployment of future soil and water conservation measures, this study can provide a theoretical basis for adjusting the existing low‐efficiency measures.

What is the failure rate of constrained liners in complex revision total hip arthroplasty?

Recurrent hip dislocation after multiple revision total hip arthroplasty is a severe complication. Therefore, constrained acetabular liners (CL) have been used during salvage procedures. We report our experience of constrained liners in a re-revision setting with focus on re-dislocation. We also evaluated acetabular and femoral bone loss as potential risk factor. Between January 2013 and December 2016, 65 patients were treated in a single institution for revision and re-revision hip arthroplasty using CL. The indication for using a CL was a high risk of re-redislocation after multiple recurrent hip dislocation including failed Dual Mobility Cups (DMC). Compromising soft tissue defects as well as severe bone defect were therefore regarded as high risks. Thirty-eight patients (77.6%) underwent a minimum of three surgical procedures before the index revision procedure. Sixteen patients (24.6%) were excluded as they were lost to follow-up, expired before minimum follow-up or refused study participation, leaving 49 patients in the analysis (75.4%). The mean follow-up was 62months (44-74; SD = 7.7). We assessed the following potential risk factors for revision or dislocation: type of surgical setting (septic/aseptic), BMI, cup inclination angle, size of liner used and acetabular and femoral bone loss according to Paprosky classification. The primary endpoints were dislocation or repeat revision for any reason. Of the 49 patients, we found an overall re-revision rate of 40.8% (20/49) and a dislocation rate of 30.6% (15/49). There were no significant differences among the surgical re-revision rate or dislocation rate as a factor of patient characteristics. In terms of bone loss, there was a trend towards higher revision rates for increasing acetabular and femoral bone loss, but without statistical significance. We found the use of a constrained liner in a re-revision setting still bears a high risk of re-revision and re-dislocation. Therefore we restrained from using constrained liners in favour of Dual mobility cups. In this study there was no significant higher dislocation rate in the subgroup of periprosthetic infection. Furthermore the rigid design of a constrained liner bears the known risk of structural failure of acetabular reconstruction implants. Severe acetabular or femoral bone defects seem to have an impact on the revision rate, but not on the dislocation rate with regards to the restored offset and center of the hip. Results have to be taken into context such that the study population inherently has a predisposition for poorer outcomes. Indications should be strongly filtered for patients at high risk for recurrent hip joint dislocation including failed DMCs with only limited bone loss and moderate soft tissue defects. Our modification to the existing classification with a high inter and intraobserver reliability will make future studies more comparable regarding revisions and bone stock loss. Still furtherresearch using objective and reproducible parameters is needed to better analyze data especially in the background of complex revision hip arthroplasty.

Study on mechanical model and shaking table test of spherical tank rolling isolation

AbstractThis paper proposed a spherical tank rolling isolation structural system assembled by the spherical tank, I‐steel ring beam and rolling isolation devices, and carried out the corresponding mechanical model research and shaking table test. First, a restoring force model for rolling isolation device with symmetrical concave surface was introduced. Based on the restoring force model and potential fluid theory, a mechanical model considering the interaction of fluid, support and rolling isolation layer was established. Numerical analysis results show that the rolling isolation reduction ratio always remains high at different liquid level heights. Shaking table tests were carried out to study the damping performance of the spherical tank rolling isolation structural system, and to provide verification for the established mechanical model. Test results showed that the seismic response of the spherical tank rolling isolation structural system was much lower than that of the nonisolated spherical tank. The reduction ratio of acceleration and support deformation can reach 56% to 82%, which greatly reduced the risk of structural failure. In addition, the calculated results of the mechanical model were in good agreement with the test results.

Arthroscopic Rotator Cuff Repair with Biphasic Interpositional Allograft Augmentation

Rotator cuff repair in the setting of a chronic tear or poor tissue quality presents a surgical challenge because of the high risk of structural failure. Patients with an increased risk of retear may be candidates for enthesis augmentation with a novel, biphasic allograft, composed of a demineralized cancellous matrix with a layer of mineralized bone. This interpositional graft was designed with the intention to promote both soft-tissue and osseous integration into the matrix, thereby conferring greater stability and regeneration of the transitional zone of the rotator cuff enthesis. Here, we describe a technique for a transosseous-equivalent supraspinatus repair with placement of a biphasic interpositional allograft.

Inspection and maintenance planning for offshore wind structural components: integrating fatigue failure criteria with Bayesian networks and Markov decision processes

Exposed to the cyclic action of wind and waves, offshore wind structures are subject to fatigue deterioration processes throughout their operational life, therefore constituting a structural failure risk. In order to control the risk of adverse events, physics-based deterioration models, which often contain significant uncertainties, can be updated with information collected from inspections, thus enabling decision-makers to dictate more optimal and informed maintenance interventions. The identified decision rules are, however, influenced by the deterioration model and failure criterion specified in the formulation of the pre-posterior decision-making problem. In this paper, fatigue failure criteria are integrated with Bayesian networks and Markov decision processes. The proposed methodology is implemented in the numerical experiments, specified with various crack growth models and failure criteria, for the optimal management of an offshore wind structural detail under fatigue deterioration. Within the experiments, the crack propagation, structural reliability estimates, and the optimal policies derived through heuristics and partially observable Markov decision processes (POMDPs) are thoroughly analysed, demonstrating the capability of failure assessment diagram to model the structural redundancy in offshore wind substructures, as well as the adaptability of POMDP policies.