Stability Calculations Research Articles

Stability analysis of loess fill slope supported by frame prestressed anchors considering tensile strength cut-off

In the stability analysis of loess fill slope, the fissure nature of loess is often ignored, which makes the stability calculation of fill slope too conservative. Based on the upper limit theory of plastic limit analysis, the stability analysis model of loess-filled fissured slope supported by frame prestressed anchors was established. Considering the tensile strength cut-off yield property of soil, the stability coefficient of slope was calculated, and the influence of different factors on slope stability was analyzed. The results show that ignoring the fissures in loess will overestimate the stability of the fill slope, and the support structure can significantly improve the stability of the loess-filled fissure slope. The research results of this paper can further enrich the stability analysis theory of loess-filled fissured slope supported by frame prestressed anchors, which is of great significance to guide engineering practice.

Causes of Pit Wall Failure in Zhelezny Mine by Radar Monitoring and Stability Calculations

Causes of Pit Wall Failure in Zhelezny Mine by Radar Monitoring and Stability Calculations

Stress field and stability calculation method for unloading slope considering the influence of terrain

Stress field and stability calculation method for unloading slope considering the influence of terrain

Predictive Model for Hydrostatic Curves of Chine-Type Small Ships Based on Deep Learning

Capsizing accidents are regarded as marine accidents with a high rate of casualties per accident. Approximately 89% of all such accidents involve small ships (vessels with gross tonnage of less than 10 tons). Stability calculations are critical for assessing the risk of capsizing incidents and evaluating a ship’s seaworthiness. Despite the high frequency of capsizing accidents involving them, small ships are generally exempt from adhering to stability regulations, thus remaining systemically exposed to the risk of capsizing. Moreover, the absence of essential design documents complicates direct ship stability calculations. This study utilizes hull form feature data—obtained from the general arrangement of small ships—as input for a deep learning model. The model is structured as a multilayer neural network and aims to infer hydrostatic curves, which are required data for stability calculations.

Efficient hydraulic and thermal simulation model of the multi-phase natural gas production system with variable speed compressors

The natural gas production system is a very complex system, involving pipelines, compressors and valves with different structures and calculation parameters. It can be divided into two different parts: gas production and collection pipe networks. Fluid flow in the gas production pipe network is multi-phase flow. Fluid flow in the gas collection pipe network is single-phase flow. It is imperative to consider gas production and collection pipe networks in conjunction to ensure accurate operation simulation. The complexity of the network structures and flow statuses can cause computational instability or even divergence problems in simulations when coupling these two types of pipe networks. To address this issue, an automatic and practical node numbering method is proposed for the large-scale pipe network, which can ensure the full rank of the solution matrix and computational stability. On the other hand, due to the need for frequent adjustments of the pipe networks to satisfy the production demand, computational boundary treatments of constant inlet/outlet pressure, constant flow rate or constant pressure ratio for the compressor stations are not suitable. To address this issue, the characteristic curves of compressors are coupled into the simulation of pipe networks to represent the variable-speed centrifugal and reciprocating compressors.The accuracy and robustness of the proposed models and numerical methods are validated through comparisons with software results and field data. The simulation time is only within 0.5 s for the natural gas production system with 210 nodes and 176 pipelines. Our model has relative deviations within 3% in both pressure and flow rate compared to field data and within 10% compared to software.

Analysis of the effectiveness of landslide stabilization in a near-dam reservoir area

The geological conditions of the landslide area in a near-dam reservoir area of a water conservancy hub project are complicated, and the stability problem of the landslide body is prominent, which is not only directly related to the safety of the adjacent office building and highway, but also poses a threat to the normal operation of the water conservancy hub. According to the latest geological data of the landslide area, the results of the stability calculation of the landslide body are analyzed, and the reinforcement design scheme of circular chair type anti-slide piles & prestressed anchor cables is proposed for the landslide body to solve the problem of anti-slide stability of the landslide body. Numerical analysis results show that: the safety factor under each working condition after reinforcement is within the permissible range and meets the relevant normative requirements, the landslide body has good control effect on deformation after reinforcement, and the reinforcement measures can provide certain reference value for the design and construction of similar projects.

Calculation of stability of constructions with intermittent parameters during seismic impact

Calculation of stability of constructions with intermittent parameters during seismic impact

Calculation of slope stability against erosion deformations

The paper considers the problems of erosion deformations occurrence for non-flooded slopes of railroad earth bed, where the main causes of scour are atmospheric precipitation or longitudinal currents along the bottom of the slope. The local stability of slopes is calculated taking into account the estimated velocity of water flow on the slope when water moves along the slope. Climatic conditions and soil characteristics on the Bukhara-Misken line were used for calculations. If local stability of slopes is not ensured, measures for slope stabilization are appointed. The technology of reinforcement of embankment slopes with geosynthetic materials with backfilling with a layer of vegetative soil and grass sowing is considered. The stability coefficient on the displacement surface is calculated taking into account the application of the selected reinforcement design. The stability coefficient on the displacement surface taking into account geomat reinforcement increased 3 times and exceeded the permissible minimum value.

Calculation of Seismic Stability of Buildings in the Far North Using the Grid-Characteristic Method

Calculation of Seismic Stability of Buildings in the Far North Using the Grid-Characteristic Method

A polygonal topology optimization method based on the alternating active-phase algorithm

<abstract> <p>We propose a polygonal topology optimization method combined with the alternating active-phase algorithm to address the multi-material problems. During the process of topology optimization, the polygonal elements generated by signed distance functions are utilized to discretize the structural design domain. The volume fraction of each material is considered as a design variable and mapped to its corresponding element variable through a filtering matrix. This method is used to solve a multi-material structural topology optimization problem of minimizing compliance, in which a descriptive model is established by using the alternating active-phase algorithm and the solid isotropic microstructure with penalty theory. This method can accomplish the topology optimization of multi-material structures with complex curve boundaries, eliminate the phenomena of checkerboard patterns and a one-node connection, and avoid sensitivity filtering. In addition, this method possesses fine numerical stability and high calculation accuracy compared to the topology optimization methods that use quadrilateral elements or triangle elements. The effectiveness and feasibility of this method are demonstrated through several commonly used and representative numerical examples.</p> </abstract>

Effect of Sintering Temperature on Phase Formation and Mechanical Properties of Al–Cu–Li Alloy Prepared from Secondary Aluminum Powders

Aluminum and its alloys are very versatile materials used in a wide range of applications due to the initial characteristics of pure aluminum and the combination of properties obtained from its blend with other elements. Considering that aluminum is the second-most-produced metal after steel, and that its production will increase over time based on the demand to produce products through conventional and additive methodologies, this will lead to an increase in the energy consumed as well as the footprint of carbon generated. It is for this reason that the generation of competitive aluminum alloys must be approached from secondary sources (recycling). To address these environmental issues, in this work, 2070 aluminum alloy (AA2070) samples were manufactured using secondary aluminum powder and compared with the primary aluminum source. The samples were compacted at 700 MPa and sintered at a different range of temperatures between 525 °C and 575 °C. The study includes thermodynamic modeling, microstructure, and mechanical characterization. Microstructure and phases characterization were carried out via scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, respectively, whereas the mechanical characterization comprised relative density evaluation, hardness, and flexion tests. Results were compared with the calculation of phase stability using Thermo-Calc software 2020a. Based on the results obtained, it can be concluded that the secondary AA2070 optimal sintered temperature, where the components raised the highest mechanical properties and effective relative density range, is 575 °C. Furthermore, the recycled alloys have similar relative densities and flexural strengths than the corresponding alloys made from primary aluminum powder.

IMO-COMPLIANT ANALYSIS OF THE LARGE ANGLE STABILITY OF CHEMICAL TANKERS DURING THE LOADING AND UNLOADING LIQUID CAUSTIC SODA

MT. Sinar Masela 8831 DWT is a ship transporting oil and chemicals certified by IMO Chemical Class 2,3. According to Chapter B, SOLAS CHAPTER VII, regarding water safety, loading and unloading oil and chemicals is categorized as dangerous due to water damage and pollution. Various studies are needed to expedite the loading and unloading process to reduce damage and pollution in the waters. One of these studies is regarding the stability of ships in accordance with IMO criteria. The study was conducted to determine the ship stability on the MT. Sinar Masela is in the loading-unloading process. This study applies eight conditions with seven-compartment tanks on the ship using software to analyze the stability calculation when the loading-unloading process meets the stability criteria set by IMO A.749(18) Ch 3. The results show the measure of stability in eight conditions with a seven-compartment tank during the loading and unloading process has a higher GZ value in all states, which has met the IMO stability criteria. Comparison of stability calculations on loading and unloading has an average difference of 0.226 m at 2.075 deg at the GZ value in each condition.

C3N-supported ⅢA group metal single-atom catalysts with different coordination microenvironments: Electrocatalytic NO reduction to ammonia

Electrochemical NO reduction reaction (NORR) to NH3 is regarded as a low-cost and environmentally friendly method that can simultaneously remove harmful NO and synthesize useful NH3. Using main group metal (MGM) atoms as active centers has the potential to enhance the selectivity of single-atom catalysts (SACs) for NH3. Herein, we selected Al, Ga and In atoms as active centers and designed 12 MGM SACs supported on the defective C3N monolayer with four coordination environments: MGM-C2N, MGM-C3, MGM-C2N2 and MGM-C4. Based on density functional theory (DFT) calculations, the NORR electrocatalytic performance of these 12 SACs were systematically investigated. Detailed studies on the NORR mechanism show that seven of these SACs exhibit excellent activity in reducing NO to NH3, effectively preventing the formation of byproducts (N2O, N2 and H2). Further stability calculations led to the identification of five promising NORR electrocatalysts with both excellent catalytic performance and stability: Al/Ga/In-C2N2 and Ga/In-C4. Moreover, the Bader charge (QMGM) of the MGM atom was used to explain the variation in activity resulting from different coordination environments. This work not only provides valuable insights for future exploration of MGM SACs, but also contributes to a better understanding of the impact of coordination environments on catalytic activity.

FLAC3D-based slope stability analysis and calculation

Slope stability is related to the normal operation of the project and operational safety, and there have been various methods for evaluating slope stability for a long time, among which the numerical analysis method is the most popular and comprehensive analysis and evaluation method nowadays. In this paper, the numerical simulation is carried out by FLAC3D software to solve the safety coefficient of the slope and the slope stability analysis in combination with the slope of the inverted siphon entry road section at the beginning of Xiaoyuiba, and the conclusions are in line with the actual situation, which shows that FLAC3D software can carry out scientific analysis and evaluation of slope stability and make comprehensive judgement.

Comprehensive mapping of mutations in TDP-43 and α-Synuclein that affect stability and binding

Abnormal aggregation and amyloid inclusions of TAR DNA-binding protein 43 (TDP-43) and α-Synuclein (α-Syn) are frequently co-observed in amyotrophic lateral sclerosis, Parkinson’s disease, and Alzheimer’s disease. Several reports showed TDP-43 C-terminal domain (CTD) and α-Syn interact with each other and the aggregates of these two proteins colocalized together in different cellular and animal models. Molecular dynamics simulation was conducted to elucidate the stability of the TDP-43 and Syn complex structure. The interfacial mutations in protein complexes changes the stability and binding affinity of the protein that may cause diseases. Here, we have utilized the computational saturation mutagenesis approach including structure-based stability and binding energy calculations to compute the systemic effects of missense mutations of TDP-43 CTD and α-Syn on protein stability and binding affinity. Most of the interfacial mutations of CTD and α-Syn were found to destabilize the protein and reduced the protein binding affinity. The results thus shed light on the functional consequences of missense mutations observed in TDP-43 associated proteinopathies and may provide the mechanisms of co-morbidities involving these two proteins. Communicated by Ramaswamy H. Sarma

Cryo-EM structures of the D290V mutant of the hnRNPA2 low-complexity domain suggests how D290V affects phase separation and aggregation

hnRNPA2 is a human ribonucleoprotein that transports RNA to designated locations for translation via its ability to phase separate. Its mutated form, D290V, is implicated in MultiSystem Proteinopathy known to afflict two families, mainly with myopathy and Paget’s Disease of Bone. Here, we investigate this mutant form of hnRNPA2 by determining cryo-EM structures of the recombinant D290V low complexity domain (LCD). We find that the mutant form of hnRNPA2 differs from the wildtype fibrils in four ways. In contrast to the wildtype fibrils, the PY-nuclear localization signals in the fibril cores of all three mutant polymorphs are less accessible to chaperones. Also, the mutant fibrils are more stable than wildtype fibrils as judged by phase separation, thermal stability, and energetic calculations. Similar to other pathogenic amyloids, the mutant fibrils are polymorphic. Thus, these structures offer evidence to explain how a D-to-V missense mutation diverts the assembly of reversible, functional amyloid-like fibrils into the assembly of pathogenic amyloid, and may shed light on analogous conversions occurring in other ribonucleoproteins that lead to neurological diseases such as ALS and FTD.

Slope stability calculation based on sparrow search algorithm and Monte Carlo simulation

Slope stability calculation based on sparrow search algorithm and Monte Carlo simulation

Some aspects of mechanical stability of centuries-old <i>Pinus pinea</i> L. trees growing in the Crimea

The paper considers the issues of assessing the mechanical stability and accident rate of the Italian pine, using the example of a 120 year-old tree growing in the conditions of the recreationally loaded territory of the A.P. Chekhov House-Museum in the city of Yalta, Republic of Crimea. It was found that the viability of the studied plant is 1 point – this is a healthy plant without damage to the trunk and crown. Biomechanical studies were carried out: the aboveground phytomass of the trunk of the tree under study and the main skeletal branches with needles were calculated, the physico-mechanical properties of tissues were determined and model calculations of the mechanical stability of the tree were performed. It was found that the dimensions of the main skeletal branches are separate independent trees, and the calculated weight is an additional static load on the trunk and under the action of a dynamic factor, which additionally reduces the critical load by ~ 20% and increases the accident rate of the entire tree. A large angle of inclination, taking into account the length of the branches, also increases the degree of accident. As a result, there is a shift in the center of mass and a tilt of the entire body with a high probability of falling out of the tree with the slab. To reduce the accident rate of a tree, it is necessary to trim the main branches and reduce the load on the trunk, taking into account the center of mass, and if it is impossible to carry out the necessary trimming, it is necessary to fix dangerous skeletal branches to metal structures.

TWIP-assisted Zr alloys for medical applications: Design strategy, mechanical properties and first biocompatibility assessment

This study proposes a novel strategy for the design of a new family of metastable Zr alloys. These alloys offer improved mechanical properties for implants, particularly in applications where conventional stainless steels and Co-Cr alloys are currently used but lack suitability. The design approach is based on the controlled twinning-induced plasticity (TWIP) effect, significantly enhancing the ductility and strain-hardenability of the Zr alloys. In order to draw a “blueprint” for the compositional design of biomedical TWIP (Bio-TWIP) Zr alloys—using only non-toxic elements, the study combines d-electron phase stability calculations (specifically bond order (Bo) and mean d-orbital energy (Md)) with a systematic experimental screening of active deformation mechanisms within the Zr-Nb-Sn alloy system. This research aids in accurately identifying the TWIP line, which signifies the mechanism shift between TWIP and classic slip as the primary deformation mechanism. To demonstrate the efficacy of the TWIP mechanism in enhancing mechanical properties, Zr-12Nb-2Sn, Zr-13Nb-1Sn, and Zr-14Nb-3Sn alloys are selected. Results indicate that the TWIP mechanism leads to a significant improvement of strain-hardening rate and a uniform elongation of ∼20% in Zr-12Nb-2Sn, which displays both {332}<113> mechanical twinning and dislocation slip as the primary deformation mechanisms. Conversely, Zr-14Nb-3Sn exhibits the typical mechanical properties found in stable body-centered cubic (BCC) alloys, characterized by the sole occurrence of dislocation slip. Cell viability tests confirm the superior biocompatibility of Zr-Nb-based alloys with deformation twins on the surface, in line with existing literature. Based on the whole set of results, a comprehensive design diagram is proposed.

Features of the methods of the slope stability evaluation

Solving slope stability problems and selecting optimal calculation methods remains an urgent problem. A significant variety of engineering and geological conditions, and a large number of factors that can affect the stability of the slope, lead to the need to select a calculation method in each specific case.&#x0D; The article examines the features of the two most common methods of calculating the stability of slopes and slopes in geotechnical practice. The first group - limit equilibrium methods, has been widely tested and is the basis of simple engineering calculations of slope stability. Within the framework of the article, the circular cylindrical sliding surface method based on the method of moments, the method of horizontal forces, the methods of tangential forces based on the analytical method of H.M. Shakhunyanets, with the introduction of calculation schemes and the mathematical apparatus of these methods, are considered. The method of L. P. Yasyunas was also noted due to the idea he highlighted of simplifying calculations using unit shear pressure, which is generally an interesting idea but has certain difficulties in practical implementation. The key advantages and disadvantages of the finite element method for solving slope stability problems are given. The question of combining MSE with the method of reducing strength to determine the coefficient of stability of slopes is highlighted.&#x0D; Several software complexes are presented that allow us to automatically determine the coefficient of stability of slopes based on different groups of methods. A comparative calculation of the imaginary slope of PC "Plaxis 2D" and "Ukis" was performed. Two formulations of the problem are considered: for a free slope and with an additional load in the upper part of the slope. The received coefficients of stability and the shape of the sliding surface were analyzed and a generalized table of results was formed. The displayed results demonstrate sufficient convergence, which confirms the possibility of using the specified methods in engineering practice to determine the stability coefficient of slopes.