Proposed Calculation Method Research Articles

Assessment of the Probability of Exceeding the Limiting Deformations of a Building Foundation

Abstract The level of ground settlement under the effect of certain factors is one of the markers indicating the adequacy of adopted design solutions. By comprehending settlement values, it is possible to infer the degree of risk associated with a project and, if necessary, introduce changes to the design. The concept of reliability management here manifests itself in the timely adjustment of the decisions made, while it is necessary to use the procedure of the quantitative assessment of the probability of the occurrence of a particular limit state. A qualitative assessment indicates only the limits of an area, which approximately characterizes the effects of changes in the geotechnical situation. In this article, a method for determining the probability of exceeding the limit deformation of a building-base massif using the Monte Carlo statistical method is developed, and an algorithm and computer program implementing the proposed calculation method are created.

Prediction of Strap Joint Design Margin in After Treatment System

The automotive vehicle has an exhaust system, also known as the after treatment System. It consists of different components such as Diesel Oxidation catalysts (DOC), Diesel Particulate Filters (DPF), Selective Catalytic Reduction Systems (SCR), etc. These components are mounted in the chassis with the help of strap joints. The strap joints provide flexible and serviceable connections between ATS bodies and chassis. The strap joint assembly consists of a T bolt, trunnion, and nut with strap. As the nut tightened, the tension induced in the strap, which results in clamping the body. If the tension in the strap is not sufficient, it may cause the failure of the joint. The failure can be yielding of material, slipping, and separation of the body. The strap joint should be designed so that these kinds of failures can be avoided. This paper presents the work on the calculation of the design margin using analytical and FEA methods. The failure modes addressed in this paper are yielding of the strap joint due to applied preload on the T bolt, slipping, and separation of the ATS body from the strap due to the application of dynamic loads such as acceleration G loads in multiple directions. The acceleration load is calculated from the PSD profile. For calculating design margins from the FEA method, nonlinear analysis is performed, followed by PSD analysis to estimate the bracket reaction forces. These reaction forces are used to calculate slip and separation margins. The tests were performed under similar conditions on a shaker table, and the results from both analytical and FEA methods were correlated with test observations to validate the proposed method of calculation of strap join design margin.

Design theory and numerical analysis of earthquake‐resilient joint with slotted bolted connection

SummaryBolted connections are preferred in prefabricated steel structures with the advantages of quality control and convenient construction. An innovative type of earthquake‐resilient joint with slotted bolted connection (ERJ‐SBC) is proposed to achieve damage control and improve the ductile behavior of steel structures. The bending moment is assumed to be mainly transferred by the flange segments of SBC while the shear force is carried by the web segments. The energy dissipation capacity of ERJ‐SBC is provided by the initial frictional sliding and inelastic axial deformation of SBC under larger displacement. Design theory is proposed to ensure that inelastic deformation is concentrated in SBC while other structural members remain elastic. The influences of the length of slotted holes, bolt pretension, friction coefficient, and the thickness and width of the sliding plate are investigated through the numerical analysis of 44 FE examples. The calculation of the critical length of slotted holes for the ductile rotation behavior of ERJ‐SBC is derived and verified. Results demonstrate that the mechanism of bolted connection shifts from friction resistance to bearing resistance when bolts collide with slotted holes, and the friction slippage behavior with slotted holes benefits the hysteresis behavior, deformation capacity, and rotation behavior. The proposed calculation methods for the mechanical behavior of ERJ‐SBC could achieve good accuracy with simulation results. A reasonably well‐designed ERJ‐SBC could have good bearing capacity and rotation behavior, and it could also achieve damage control.

Fast Hologram Calculation Method Based on Wavefront Precise Diffraction.

In this paper, a fast hologram calculation method based on wavefront precise diffraction is proposed. By analyzing the diffraction characteristics of the object point on the 3D object, the effective viewing area of the reproduced image is analyzed. Based on the effective viewing area, the effective hologram size of the object point is obtained, and then the accurate diffraction calculation from the object point to the wavefront recording plane (WRP) is performed. By calculating all the object points on the recorded object, the optimized WRP of the whole 3D object can be obtained. The final hologram is obtained by calculating the diffraction light field from the WRP to the holographic plane. Compared with the traditional method, the proposed method can improve the calculation speed by more than 55%, while the image quality of the holographic 3D display is not affected. The proposed calculation method provides an idea for fast calculation of holograms and is expected to contribute to the development of dynamic holographic displays.

Investigation of Heat and Mass Transfer in the Process of Fuel Preparation from Biomass Particles with High Moisture

Currently, in a number of countries an urgent task for development of fuel and energy complexes is to increase the share of generation by involving solid fuels in circulation. Among such projects, those that allow the disposal of waste from various industries are particularly significant. Expired food products in this context are represented as a renewable local energy resource. However, such products require serious activities to prepare them for incineration or other type of high-temperature processing in order to obtain energy. The purpose of the present work is to improve methods of preparing fuel from recycled carrot fruits (unsuitable for use in the food sector). During the fuel preparation of carrots, the drying stage is limiting for the rational organization of its processing in boilers. In addition, the drying stage is extremely energy-consuming, so reliable prediction of its kinetics largely determines the efficiency of the entire technological process. In the course of the study, the following tasks were solved: a numerical method was developed for describing the processes of internal and external heat and mass transfer problems using an explicit difference approximation of differential equations of heat and mass transfer; parametric identification of the proposed one-dimensional mathematical model was performed using empirical dependencies known from literature sources; empirical verification of the proposed mathematical model was carried out by comparing the calculated forecasts obtained with the results of their own field experiments. The fact that the proposed mathematical model and the results of the full-scale experiment are independent, while the calculated forecasts and experimental data are in good agreement, makes us possible to consider the proposed calculation method as a reliable scientific basis for a computer method for calculating of heat and mass transfer processes when organizing the preparation of fuel from carrot fruits.

Evaluation of the Usefulness of Topological Indices for Predicting Selected Physicochemical Properties of Bioactive Substances with Anti-Androgenic and Hypouricemic Activity.

Due to the observed increase in the importance of computational methods in determining selected physicochemical parameters of biologically active compounds that are key to understanding their ADME/T profile, such as lipophilicity, there is a great need to work on accurate and precise in silico models based on some structural descriptors, such as topological indices for predicting lipophilicity of certain anti-androgenic and hypouricemic agents and their derivatives, for which the experimental lipophilicity parameter is not accurately described in the available literature, e.g., febuxostat, oxypurinol, ailanthone, abiraterone and teriflunomide. Therefore, the following topological indices were accurately calculated in this paper: Gutman (M, Mν), Randić (0χ, 1χ, 0χν, 1χν), Wiener (W), Rouvray-Crafford (R) and Pyka (A, 0B, 1B) for the selected anti-androgenic drugs (abiraterone, bicalutamide, flutamide, nilutamide, leflunomide, teriflunomide, ailanthone) and some hypouricemic compounds (allopurinol, oxypurinol, febuxostat). Linear regression analysis was used to create simple linear correlations between the newly calculated topological indices and some physicochemical parameters, including lipophilicity descriptors of the tested compounds (previously obtained by TLC and theoretical methods). Our studies confirmed the usefulness of the obtained linear regression equations based on topological indices to predict ADME/T important parameters, such as lipophilicity descriptors of tested compounds with anti-androgenic and hypouricemic effects. The proposed calculation method based on topological indices is fast, easy to use and avoids valuable and lengthy laboratory experiments required in the case of experimental ADME/T studies.

Tensile Behaviors of Textile Grid–Reinforced Engineered Geopolymer Composites

This paper presents a study of the tensile behaviors of textile grid–reinforced engineered geopolymer composites (TR-EGCs) using both experimental and numerical methods. EGC is a novel ecofriendly fiber-reinforced geopolymer composite that exhibits ultrahigh ductility under tensile loading conditions. In this paper, the ambient cured EGC with local polyvinyl alcohol (PVA) fiber was designed and the mechanical behaviors of the EGC were investigated. Direct tensile tests of TR-EGC specimens were conducted and compared with those of conventional textile-reinforced mortar (TRM). It was found that the load-carrying capacity of TR-EGC with carbon fabric was 5.72 times greater than that of TRM. The influences of alkali concentrations and textile types on the tensile behaviors of TR-EGC are discussed. It was found that the increase of alkali concentration is beneficial to the tensile strength of EGC and TR-EGC. In contrast, the tensile ductility decreased gradually as the alkali concentration increased from 4 to 12 mol/L. A finite-element (FE) model is proposed to model the tensile behaviors of TR-EGC specimens, which was verified using the experimental results. Because the current calculation method significantly underestimated the composite behaviors of the EGC and the inner textile, a new calculation method is proposed. It was found that the proposed calculation method is more accurate in predicting the tensile load–carrying capacity of TR-EGC, although more experiments and numerical analyses with in-depth discussions still need to be conducted.

Uncertainty model for rate of change of frequency analysis with high renewable energy participation

<span lang="EN-US">Large-scale integration of inverter-based renewables is displacing synchronous machine generation, causing a reduction in the inertia of electrical power systems. This reduction is reflected in an increase in the rate of change of frequency (RoCoF). Additionally, the variation of the RoCoF will depend on the uncertainty associated with the generation of non-conventional renewable energy sources. For the planning of the operation of the system, it is essential to know the range of variation of the RoCoF when there are disturbances in the system and uncertainties in the generation of non-conventional sources of renewable energy. This paper proposes to establish the calculation of a confidence interval of the RoCoF variation that considers these uncertainties. So, this paper proposes a method to consider these uncertainties based on the probabilistic point estimate method (PEM); considering multiple renewable non-conventional sources with correlated or uncorrelated behavior in their powers injected into the system. On the other hand, as there are different proposals to calculate the RoCoF, this paper presents the application of the uncertainty model with three different RoCoF proposed calculation methods.</span>

Detection of gaseous halocarbon refrigerants and extinguishing agent based on photoacoustic spectroscopy

A photoacoustic (PA) gaseous halocarbon refrigerants and extinguishing agent detector based on a mid-infrared broadband source was developed. H1301 (extinguishing agent), R134a and R410A (refrigerants) were the target gases. A mid-infrared thermal radiation source radiated along the longitudinal direction of the cylindrical PA cell and was reflected by a gold-plated mirror to excite PA signals. The concentrations of CO2 and H2O were measured to reduce their interference. The PA signals of H1301, R134a, R410A, CO2 and H2O were excited by using a thermal radiation source with five different optical filters, respectively. The fundamental-frequency intensity modulation (1f-IM) technique was used to measure the generated PA signals. The detection limits (1σ) of H1301, R134a and R410A were 49 ppb, 80 ppb and 211 ppb with an average time of 100 s, respectively. According to the absorption spectrum of the three target gases, there are strong cross interference around the wavelength of 8.5 µm. By using the proposed calculation method to obtain the concentrations of the target gases, the high cross interference among these gases is reduced to less than 2 %.

A Target Damage Effectiveness Assessment Mathematical Calculation Method with Uncertain Information Based on an Adaptive Fuzzy Neural Network

Aiming to address the issue of assessing the effectiveness of target damage in air defense interception under projectile and target intersection, this paper proposes a novel target damage effectiveness assessment mathematical calculation method using an adaptive fuzzy neural network. The design and calculation methods introduce the target cabin’s damage weight factor, the dispersion error and coverage density and fire density of warhead fragment, and the ratio of the number of warhead fragments to the cross-sectional area of the target as the primary damage factors, and we establish a new model for calculating the target damage efficiency using Takagi-Sugeno adaptive fuzzy neural network with the multiple damage factors. In the designed model, we take the characteristic parameters of warhead fragments formed by the projectile explosion as the sample data and learn the mapping relationship between damage factors and damage effect expressed by the system of fuzzy rule. Combined with the vulnerability weight and damage factors of the target, the fuzzy rule system is applied to predict and calculate the damage probability and damage effectiveness. In addition, we use shot-line technology to set up the intersection criterion between warhead fragments and target, analyze the coordinate relationship of the projectile explosion relative to the target based on the ground coordinate system, and derive the distribution density function of warhead fragment and research a calculation model for target damage probability with multiple vulnerable cabins. Finally, we use the established model to train, test, and calculate the data from the actual projectile and target intersection damage test and present the comparison results to other damage calculation methods. By calculation and comparative analysis, the results show the smaller the distance between projectile and target, as well as the smaller the average intersection angle, and the larger the weight coefficient of the warhead fragment covering the target cabin, the total target damage probability increases obviously. In the two experimental calculations, the target cabin with the largest weight coefficient was considered, and compared with the existing literature, the damage probability of the proposed calculation method was increased by 9.13% and 10.93%, respectively, and it is clear that the proposed target damage assessment method can effectively reflect the real target damage effectiveness in the state of projectile and target intersection.

A novel method to measure the energy efficiency and performance of an auto-cascade refrigeration cycle

Auto-cascade refrigeration systems are the most used cycles to maintain spaces at ultra-low temperature conditions (-80 to −60 °C). The interest in these systems has risen due to the need to maintain and distribute COVID-19 vaccines. However, there is a lack of experimental validation of the theoretical models that are used to analyse and optimize them. In this work, a novel method to calculate the thermodynamic performance, circulating compositions, and energy efficiency of an auto-cascade refrigeration system is presented. The method is based on the measurements of an experimental auto-cascade plant at temperatures from −83.0 to −59.9 °C. The results of the study showed that the proposed calculation method was able to accurately predict the thermodynamic performance, circulating compositions and energy efficiency of an auto-cascade system. The uncertainty of the predictions was found to be below 1% for circulating compositions and 5.2% for the cooling capacity and COP.

Determination of online thin film buckling configuration by parametric optimization for flexible sensor application

A mini basket type mapping catheter consists of thin film flexible sensors and is applied in the medical field to measure the electrocardiography (ECG) signals in order to localize and quantize the physiological condition/status of heart. The flexible nature of the thin film changes the configuration with respect to the contact boundary conditions when it contacts a target surface. Therefore, to accurately localize the flexible sensor, the thin film flexible sensor’s configuration must be determined accurately in an on-line fashion. As a study of localizing the thin film flexible sensor, this study proposes an on-line thin film buckling configuration determination method using parametric optimization and interpolation technique. With the specific modulus of elasticity and dimensions of the thin film flexible sensor of the mapping catheter prototype, the buckling configuration with two point boundary condition under axial load can be calculated in desktop environment. The proposed calculation method is validated by mapping catheter sensor prototype test. The calculation/test results showed that the maximum overall length L, x_{a}, and y_{a} value error between the calculation and experiment are approximately 0.16 mm, − 0.12 mm. − 0.10 mm in 50 ms calculation time. The calculation result of the proposed method is also compared with that of the numerical simulation by FEM, which has approximately 0.44 mm y_{a} value error compared with that of the experiment.

Stress-strain state and load ability of compressed pipe-concrete elements

In the article are presented the results of stress-strain state and the bearing capacity of compression pipe-concrete elements studies. The studies were carried by using a fractional-rational diagram of relationship between stress and strain proposed in the Eurocode for a compressed concrete core inside a pipe and a symmetrical two-line diagram with limited area of fluidity for any values of an arbitrary flexibility of element and eccentricity of compressive force. On the carried research basis has been developed an effective numerical technique for determining the stress-strain state and the bearing capacity of compressed pipe-concrete elements. In calculation technique constructing, the task solution is reduced to system of nonlinear algebraic equations solving, relative to the deformation level in the most stressed section of the compressed concrete core section and the position of the neutral axis in this section. The efficiency of the proposed calculation method has been verified by numerous numerical experiments. It is shown that depending on the element's flexibility and the compressive force's eccentricity, at the moment of bearing capacity loss, the operation of the steel pipe can be both elastic and elasticplastic, and this is determined only by calculations using the proposed general method. Keywords: concrete; steel pipe; «load-deflection» graph; deformation; stress; deflection; stress-strain state; bearing capacity; eccentricity.

Improvement methods for thermal backflow phenomenon in engine compartment blow-type air cooler module

Regarding the thermal backflow problem in the central area of the engine compartment's blow-type cooler module, a computational model for the entire machine's outflow field is first established and validated using experimental results. Next, the formation of thermal backflow phenomenon is analyzed, and a more accurate calculation method for the cooler that takes into account the thermal backflow phenomenon is proposed. Finally, a new structure that can eliminate the thermal backflow phenomenon is presented, and the heat dissipation effect is analyzed. The conclusion shows that the calculated values of the engine compartment cooler module are consistent with experimental results, verifying the correctness of the computational model. The negative pressure caused by the “pump” suction effect in the central area of the cooler module is the fundamental reason for the generation of the thermal backflow phenomenon. The dual heat exchanger model can significantly improve the calculation accuracy of the cooler when taking into account the thermal backflow phenomenon (by at least 10%), providing a more accurate method for evaluating the cooler's heat dissipation ability. The proposed new structure can eliminate the thermal backflow phenomenon in the cooler module and improve the heat dissipation uniformity. After the elimination of the thermal backflow phenomenon, the heat dissipation ability of the cooler is improved by at least 25%. In addition, the improvement of the heat dissipation uniformity of the cooler can effectively solve the problem that multiple coolers in the engine compartment have inconsistent heat dissipation capabilities. The proposed calculation method for the cooler taking into account the thermal backflow phenomenon and the new structure for eliminating the thermal backflow provide a reference for the development of similar products in the future.

Methodology to calculating the temperature around an evaporating droplet using a set of thermocouples

A new approach is proposed to calculating the gas/vapor temperature field in the immediate vicinity of a droplet using a set of thermocouples. The schemes used in the experiments are based on convective and combined droplet heating. The air temperature during droplet heating was varied in the range of 100–500 °C, and the droplet radii from 1 mm to 1.7 mm. The paper describes data processing algorithms and methods for calculating the gas/vapor temperature field around a droplet using three to five series of measurements and shows the advantages of this approach over non-contact optical techniques. We also determine the applicability range of the proposed method for temperature field calculation and the limits of systematic and random measurement error variation. The instantaneous droplet radius and the initial air temperature around it are shown to be the main factors influencing the gas/vapor temperature distributions around an evaporating droplet. The experimental data are compared to earlier research findings. The results indicate that reliable gas/vapor temperature fields around evaporating liquid droplets can be obtained even with inexpensive equipment.

Optimization of Main Canal Parameters in the Area of Hydraulically Most Advantageous Sections

The main canals of reclamation systems, along with the best economic performance, must also meet the requirements for connecting the conductive network in the vertical plane and the technology for the construction of the channel. Although the channels of the hydraulically most advantageous profile are the most economical un terms of excavation volume, often turn out to be too deep and of small width along the bottom, which does not meet the specified requirements. All these factors can be taken into account by slightly reducing the water flow velocity u (compared to the velocity in the channel with the most hydraulically advantageous cross section uh.a.), which leads to a significant decrease in the channel depth and, accordingly, an increase in the width of the channel along the bottom. Such a decrease in velocity is economically justified (without a significant increase in the cross-sectional area) in the region of the most hydraulically advantageous sections, where the curve of the function h = f(u) sharply increases and asymptotically approaches the ordinate with the maximum possible velocity uh.a. This area can be approximately characterized by the values of the velocity u = (0.95–1.0)uh.a. For the convenience of calculation, the formula obtained earlier by the author for the channel depth of the hydraulically most advantageous profile has been converted to a simpler form. An analytical method is proposed for calculating the optimal parameters of the channel section, located in the area of the most hydraulically advantageous sections, which is characterized by the optimization coefficient Kopt = u/uh.a, varying within Kopt. = 0.95–1.0. In this area, the cross section of the channel differs slightly from the most hydraulically advantageous profile, and, at the same time, satisfies the requirements for conjugation of the conductive network in the vertical plane and the conditions of work. The proposed calculation method is less laborious and is applicable in a wide range of changes pertaining to exponent y in the formula of N. N. Pavlovsky to determine the Chezy’s coefficient. The calculation according to the proposed method is performed based on the use of dependencies to determine the characteristics of the most hydraulically advantageous section and the formulas of channel hydraulics (with a slight gradual decrease in the water flow rate u). Formulas are obtained for determining the depth and width of the channel along the bottom at various values of velocity.

Practical Knowledge Level Characteristics and Innovative Practice Achievement Transformation Mechanism of Vocational College Students

Cultivating talents with innovation ability is both the goal of higher vocational colleges and their responsibility given by the era. Focusing on improving the practical knowledge level of students means that students should be exposed to nature, society and problems through practical activities, thus providing the maximum space for them to think, explore, discover and innovate. As for existing studies on cultivating innovative ability of students and improving their practical knowledge level, they mainly have focused on ability evaluation and analysis of influencing factors, and few of them has involved analysis of their practical knowledge level characteristics. Therefore, this paper studied the characteristics and transformation mechanism of their innovative practice achievements. A multi-level comprehensive evaluation system was constructed, which aimed to evaluate the practical knowledge level of those students. The input dimension of quantized data of indexes was reduced in accordance with the principal component analysis (PCA). Then the quantized data of the low-dimensional indexes were mined by hierarchical clustering, and different training subsets were generated to participate in the evaluation model training. Based on the idea of clustering-prediction-integration, Gated Recurrent Unit (GRU) model was used for nonlinear integration of the output results of two-way Long Short-Term Memory (LSTM) model, which further fit the nonlinear characteristics in the quantized data of all indexes. By introducing Bootstrap-Data Envelopment Analysis (DEA) method, the transformation rate of innovative practice achievements of the students was collected and calculated in order to obtain a small calculation error. Experimental results verified the effectiveness of the proposed calculation method of the model.

Calculation Method of Loose Pressure in Surrounding Rock Mass

With the implementation of the regional coordinated development strategy, traffic flow has grown explosively. The construction of a larger tunnel section becomes an effective way to solve the highway network’s insufficient transport capability problem. Currently, there is little research on the factors influencing and methods of calculating the loose pressure in the surrounding rock mass for highway tunnels with super-large cross-sections. Based on the Bifurcation Tunnel, which is one of the sign projects in the past five years, this paper discusses the influencing factors for the range of loose zone in deeply buried tunnels using a combination of a numerical analysis and an orthogonal test. The weight of influencing factors is calculated via an efficiency evaluation method. This paper establishes a limit analysis model of the loose pressure in the surrounding rock mass under a non-linear failure criterion based on the fitted boundary function and upper bound limit analysis method and deduces the correlations of the loose pressure. The distribution law of the loose pressure, obtained via the limit analysis method, is consistent with the pressure-monitoring results, verifying the correctness of the proposed calculation method. This study can provide a calculation basis for the design of a supporting structure and the selection of similar super-section tunnel projects.

Analysis and Verification of Load–Deformation Response for Rocking Self-Centering Bridge Piers

Rocking self-centering (RSC) bridge piers were proposed based on the bridge seismic resilience design theory, pushing the development of bridge sustainability. To develop a seismic design method for RSC bridge piers, a clear understanding of their behavior under earthquakes is essential. This study analyzed the whole lateral force–displacement response of RSC piers, taking into account both rotational and flexural deformation, which resulted in a clearer understanding of their behavior under seismic actions. In this study, the whole loading process was simplified into three statuses, and a calculation method was developed to determine the relationship between lateral force and displacement of both single-column and double-column RSC bridge piers. The accuracy of the proposed method was verified by comparing the calculated results with experimental data for six single-column and two double-column RSC bridge piers. The results show that the proposed calculation method predicts the initial stiffness, yield and peak loads, and yield and peak displacements well for RSC bridge piers. The method offers valuable insights into the seismic response of RSC bridge piers, which can serve as a reference for future research, promoting the safety and stability of these structures.

Estimating initiation conditions for extrusion buckling of driven open-ended piles

The potential for pile tip damage and extrusion buckling has become an increasing concern for the offshore wind industry following the trend toward the use of large-diameter thin-walled pile foundations, either as monopiles or as part of a jacket structure. Extrusion buckling may be triggered by an initial pile tip fabrication imperfection or pile damage during transport and handling. It may also be triggered during driving through strong heterogeneous sediments. Numerical analysis of the problem requires advanced and computationally expensive techniques because of the three-dimensional, dynamic and large-deformation nature of the pile and soil deformations. The problem is addressed here by combining coupled Eulerian–Lagrangian simulations with geotechnical centrifuge model test data in dry dense sand. Both approaches consider pre-dented piles with the objective of estimating the soil strength, characterised by the cone resistance, at which minor initial damage will start to propagate. Simplified analysis of structural dent propagation and radial stresses generated in the soil during advance of a deformed pile led to a simple calculation procedure to assess the potential for extrusion buckling. Reasonably good agreement was achieved between the proposed calculation method, numerical simulations and centrifuge tests data, rendering the approach a valuable screening tool for practical application.