Design Calculation Method Research Articles

A Study on the Influence of Hydraulic Compactor Reinforcement on the Force Law of an Independent Foundation Under a Column and Its Safety Standard

Due to the complexity of the actual geotechnical environment, the backfill compaction design theory and calculation method are not reflected in the current specification. Therefore, in order to investigate the effect of the hydraulic compactor on the foundation structure during the treatment of the backfill of an independent foundation under a column, the Menard formula was modified. At the same time, relying on an independent foundation project under a column in Jinan, the dynamic model of compactor tamping backfilling soil was established. The applicability of the calculation formula is verified by simulating the single-point multiple tamping on the backfill directly above the foundation tie beam, and the influence law of two factors, the thickness of the backfill and the tamping energy, on the force of the foundation tie beam is elucidated. The results show that after reaching the optimum number of tamping, the cumulative soil settlement and the effective reinforcement depth of tamping show a stable trend, and their simulation results are in good agreement with the analytical solution, which provides a supplement to the relevant safety standards. At this critical point, the force on the tie beams peaked and showed up and down fluctuations under the subsequent ramming action. The tamping action of the compactor has a significant effect on the structural forces within the effective reinforcement range, and there is a negative correlation between the magnitude of the structural forces and the thickness of the backfill. According to the numerical calculation results to choose the best construction programme, the on-site monitoring shows that under 42 KJ tamping energy and 1.5 m single backfilling thickness, the tie beam reinforcement stress reaches 18.5~55.5% of the specification warning value, which meets the safety standard. The research results of this paper can provide important guidance for the hydraulic tamping treatment of an independent foundation backfill project.

Research on the vertical compressive bearing characteristics of offshore wind power steel pipe piles

In the absence of a comparison of static load test results for large-diameter steel pipe piles at home and abroad, optimize the design parameters based on the test pile results to guide later construction. This paper is based on the pile foundation design calculation method of API specification, as well as the relationship between the t-z, Q-z, p-y curve modes suggested by this specification, vertical ultimate bearing capacity, and stratum parameters. The conclusions and results obtained are limited to pile foundation calculations using API specifications. Analyze and back-analyze the results of static load tests on large-diameter steel pipe piles, and verify the pile foundation parameters. Combined with the data obtained from the test pile tests, analyze the stratum parameters to guide the optimization design of pile foundations in the construction drawing design stage of the offshore wind farm expansion project.

Thermal design calculation method of the whole coil closed cooling tower with condensation inside the tube

In this paper, the heat exchange process of a closed cooling tower with condensation inside the tube is analyzed. Combined with the calculation method of a traditional closed cooling tower, the thermal model and mathematical model of the whole coil closed cooling tower with condensation inside the tube are established. The fourth-order Runge-Kutta (RK4) method is used to write a program to solve the differential equation. A case is calculated to solve the heat exchange area and spray water temperature. Its feasibility for design reference is verified.

Simplified nonlinear model and 3D printing model experiment verification of longitudinal joints of shield tunnel segments

The segment joints represent vulnerable and core-bearing areas within shield tunnel structures. Their flexural stiffness, starting from the contact surface of longitudinal joints to the bolt hole, exhibits continuous changes under bending loads, typically demonstrating nonlinear mechanical characteristics. This study investigates the influence of joint contact surfaces on flexural stiffness, extending from the joint contact surface to damaged concrete in the compressed zone. A new simplified model for the variable nonlinear stiffness of longitudinal segment joints in shield tunnels is proposed, considering the flexural stiffness of the joint contact surface and the width of the damaged concrete zone in the segment ring while simulating the flexural stiffness decay induced by the opening of segment joints. Based on the minimum potential energy principle, a design calculation method for joint flexural stiffness is derived, establishing the nonlinear bending stiffness coupling relationship between the segment and the joint. Through similarity theory, 3D printing technology, and indoor loading tests, the theoretical model's accuracy regarding tunnel segment joints is verified. This theoretical model provides a basis for designing and assessing the performance of tunnel-segment joints.

Litz-Wire Winding Loss Calculation Method for Optimal Design of High-Frequency Transformers

Litz-Wire Winding Loss Calculation Method for Optimal Design of High-Frequency Transformers

Research on the strength prediction for pervious concrete based on design porosity and water-to-cement ratio

Abstract The strength prediction of pervious concrete is hard to implement for the mix design due to the porous structure. This work studied the influence of the water-to-cement ratio on the fluidity, viscosity, and mechanical properties of cement paste. Then, the porosity, permeability, and compressive strength of the pervious concrete with various porosities were investigated, and the test results were fitted and analyzed. The result indicates that as the water-to-cement ratio increases, the viscosity of the cement paste reduces and the fluidity increases. The water-to-cement ratio has a negative linear relationship with net slurry strength. The porosity and permeability of pervious concrete fluctuate in accordance with the same rule as the water-to-cement ratio changes. The compressive strength of pervious concrete with varying design porosities increases initially, then declines as the water-to-cement ratio rises. According to the linear fitting analysis, when the water-to-cement ratio is constant, the permeability and compressive strength of pervious concrete have a positive and negative linear relationship with the design porosity, respectively. By analyzing the fitting results and combining the volume method of pervious concrete, a calculation method for mix proportion design is proposed to predict the strength of pervious concrete.

Fretting fatigue of cast iron and aluminium – A strength assessment method based on a worst-case assumption

Many components made of cast iron (e.g., in combustion engines) and aluminium (e.g., in aircraft construction) are subject to fretting fatigue. This results in a need for a method for assessing the strengths of the aforementioned materials that takes into account the reduction in fatigue strength due to fretting as well as the accompanying reduction in service life. In a first paper, the authors already presented a calculation method for the fail-safe design of steel–steel contacts subject to fretting fatigue. This enables the engineer or designer to perform a strength assessment for any component connection made of steel. The calculation method is based on a tribological worst-case assumption and can be integrated into the analytical strength assessment of the internationally known FKM Guideline. The strength reduction is taken into account by use of empirically determined fretting factors. The frequent failures of component connections made of cast iron and aluminium in the field made an extension of the calculation method became necessary. This work therefore includes experimental investigations into the materials EN-GJS-700, EN-GJS-400 and EN-GJL-300 (cast iron), as well as EN AW-7075 T651, EN AW-6082 T651 and EN AW-5083 (aluminium). Since the main parameters determining fretting fatigue strength are slip amplitude and contact pressure, the worst-case combinations of these parameters (resulting in the lowest friction fatigue strength) were first determined for each of the two material groups using a laboratory test setup. These parameters could be found at sa=10μm;p=40MPa for cast iron and sa=5μm;p=10MPa for aluminium. Based on these worst-cases, the fretting fatigue limits of the aforementioned materials were determined, as well as the effect of mean stress. The fretting factors of the materials were derived from the experimental results. Additional experimental investigations using a connecting-rod-like geometry served to validate an application typical of the industry. Using the calculation method, the degree of utilisation of the connecting rods could be determined with good accuracy (maximum error: 18.7%).

Study on the design calculation method and construction control method of suction drum foundation for guided frame platform

Currently, a standardized design and calculation specification for suction drum foundations has yet to exist in China. The engineering design currently depends mainly on the subjective understanding and engineering experience of the designers, which can be considered somewhat blind and subjective. In this paper, we utilize the offshore wind power project in Yangjiang City, Guangdong Province, as our case study. Building upon domestic and international research results, relevant investigations, design specifications, and engineering applications in related fields, we conduct a systematic study on the design calculation and construction control technology of the suction drum foundation. The document presents the design calculation and inspection of the suction drum foundation. Building on this foundation, we propose a sinking feasibility analysis method and a parameter value method for the suction drum foundation calculation. We also examine the suction drum foundation construction process, examining its control parameters, technology, and standards. Finally, based on the measured data from six four-barrel guided frame platform suction drum foundations that were successfully installed, the proposed design and control method are evaluated, and their effectiveness is verified. The results of this study can provide valuable references for the design and construction of similar suction drum foundation platforms.

Study on Optimal Pile Length in Load Section of Double-Row Buried Pile under Overtopping Failure Mode

An anti-slide pile is a common landslide control measure. Compared with the full-length pile whose top extends to the ground, the buried pile is more optimal in internal force distribution, saves material and has remarkable economic benefits. At present, there is a lack of in-depth theoretical analysis on the pile length of the load section of double-row buried piles. In order to establish the design calculation method of pile length in the load section of double row buried piles, this paper is based on the failure mode of overtopping. The design equation of load section pile length is obtained by using the transfer coefficient and limit equilibrium method. Taking a landslide in Yan’an City, Shaanxi Province, China, as an example, the reliability and economics of double-row buried piles are verified by comparing the treatment effects of single-row, double-row and double-row buried piles, and the engineering design is completed. The results show that the landslide control project using the design calculation method can meet the requirements of slope stability and at the same time save a quarter of the material compared with the double row of full-length piles. The engineering example proves the rationality and practicability of the design method and provides engineering reference value for the use of the double-row buried anti-slide pile structure in large-scale landslide treatment.

Dilution Refrigeration Technology

As the main means of obtaining extremely low temperatures of 10mK, dilution refrigerators are widely used in quantum computing, condensed matter physics and other fields. The development of the most widely used typical dry dilution refrigerators has been relatively mature internationally, while there is little research on other types of dilution refrigerators, and there is a lack of comprehensive and systematic research on dilution refrigeration technology.<br>This paper focuses on the current status of dilution refrigeration technology research, introduces its basic principles, and points out that the fundamental reason for continuous refrigeration is the limited solubility of 3He in 4He and the enthalpy difference between the concentrated phase and the dilute phase. The implementation forms and research progress of typical dilution refrigerators, 4He cycle dilution refrigerators, cold cycle dilution refrigerators and space dilution refrigerators are summarized, and their respective application occasions and advantages and disadvantages are discussed. The key influencing factors and design calculation methods for realizing dilution refrigerators below 10mK are analyzed from the aspects of Kapitza thermal resistance, osmotic pressure, and resistance, providing a reference for the research of dilution refrigeration technology.

Study on the analytical model of bending deformation for spliced glass beams with stainless steel bolts

To deal with the problems of high cost in super long glass manufacturing, which restricts their applications and development in glass structures, spliced glass beams (SGB) with stainless steel bolts connections was developed. The bending deformation of the SGB with stainless steel bolts have not been elucidated because it is difficult to achieve full beam equal stiffness in the splicing part. In view of this, the conjugate beam method was utilized to calculate the bending deformation of the SGB with stainless steel bolts. The bending deformation of the SGB with stainless steel bolts was investigated by the bending performance test, while the location of abrupt stiffness change and the actual correction coefficient were determined. It is verified by finite element analysis, on the basis of which the influence law of the height-to-span ratio and the height-to-thickness ratio of glass and stainless steel plate on the ultimate load and maximum deflection of SGB with stainless steel bolts were studied. The results confirmed that SGB composed of as few stainless steel bolts as possible can fully utilize the bending capacity of glass. This study provides a simplified calculation method for the engineering design of SGB, and opens up an idea for the design of glass structures.

Comprehensive Fatigue Analysis and Practical Design Methodology for Weld Toes in the Sphere of Welded Hollow Spherical Joints in Grid Structures

This paper addresses the issue of fatigue in grid structures, a topic of interest in engineering and academia. The goal is to establish a practical fatigue design calculation method for weld toes in welded hollow spherical joints (WHSJs). The study focuses on commonly used steel tube-WHSJs in grid structures, conducting 25 constant amplitude and four variable amplitude fatigue tests on tube–sphere joints (TSJs) to derive corresponding S-N curves. Using ANSYS, the hot spot stress concentration coefficient Kh at the weld toes in 22 TSJs was calculated, resulting in a numerical solution for Kh ranging from 2.0550 to 4.8600. Based on this, fatigue design methods were established using nominal stress amplitude and hot spot stress amplitude as fundamental parameters. Within a fatigue design reference period of two million cycles, the allowable nominal stress amplitude for TSJs is 22 N/mm2, and the allowable hot spot stress amplitude is 66 N/mm2. The study also conducted macroscopic and microscopic analyses on fatigue fractures of TSJs, revealing that the weld toe in the sphere of TSJs is the primary site for fatigue crack initiation. This research provides practical calculation methods for fatigue design in WHSJ grid structures, contributing to their broader application.

Numerical design calculation of the high-strength steel welds

This study focused on the design of fillet welds fabricated using high-strength steel (HSS). Herein, we present a numerical design calculation (NDC) method for assessing weld strength using the regular inclined shell element model (RISEM) in the finite element method (FEM). The NDC uses the FEM to design joints according to standardised procedures. The inclined shell element in the RISEM represents the geometry and stiffness of the welds, which controls the stresses in the plane. We recommend using a common inclined shell element with rigid links to accurately represent the geometry and rigidity of fillet welds. A new strength criterion is proposed based on the stresses on the inclined shell element, using the maximum equivalent stress as an indicator. An experiment was conducted on the transverse fillet lap-welded connection from the S700 MC Plus steel plate and OK AristoRod 13.12 electrode at room temperature. The deformation capacity of the welded connection was measured via a non-contact process using the digital image correlation (DIC) technique. This method was validated by comparing the RISEM and test results using finite element (FE) simulations. Additionally, the weld resistance computed from the analytical model of prEN 1993–1–8:2020 was in good agreement.

Solving Innovative Problems of Thrust Vector Control Based on Euler's Scientific Legacy

This study aims to develop an interdisciplinary approach to solving innovative thrust vector control problems. The methodology involves the development of a working hypothesis about the ejection process when using a controlled nozzle to deflect the thrust vector (velocity vector) in any direction within a complete geometric sphere. When developing the working hypothesis, a multilateral analysis of individual facts and scientific and technical information is performed using tools in the "big data" area, assessing opportunities to apply the "Foresight" methodology for predicting the development of fluidics. The authors propose new mathematical models to describe the thrust vector in the distribution of the mass flow rate of the fluid medium between flow channels. Patents for inventions support the novelty of scientific results that reveal new opportunities for more active development of fluidics as applied to simple and complex jet systems with low and extremely high energy density in flows. The proposed methodology rests on a modern computer base and is a logical continuation and development of well-known Euler’s works. The computer simulation of multiflow jet devices mainly focuses on power engineering, production, and processing of hydrocarbons. Some results of this research work, including patented design developments and calculation methods, also apply to developing robotics, unmanned vehicles, and programable jet systems. The authors attribute further development of the interdisciplinary approach for solving inventive problems to the use of different AI options. Doi: 10.28991/CEJ-2023-09-11-017 Full Text: PDF

Numerical design calculation of structural steel welds

This paper focuses on designing fillet welds made from high-strength steel (HSS). It presents a numerical design calculation (NDC) method for assessing weld strength using the regular inclined shell element model (RISEM) in the finite element method (FEM). NDC uses FEM to design joints according to standardised procedures. The inclined shell element in RISEM represents the geometry and stiffness of welds, controlling its stresses in the plane. The paper recommends using a common inclined shell element with rigid links to accurately represent the geometry and rigidity of fillet welds. A new strength criterion is proposed based on stresses on the inclined shell element, using maximum equivalent stress as an indicator. Validation of the method is confirmed by comparing RISEM and test results using finite element (FE) simulation. Additionally, the weld resistance computed from the equation in prEN 1993-1-8:2020 is also in good agreement.

Study on the Optimization of Pile Length of Micropiles in Soil Landslides

This study summarizes the engineering design and calculation methods of micropiles and proposes a pile length optimization model based on numerical simulation software. Based on the proposed micropile calculation method and optimization method, a specific analysis of a project example was carried out, and a series of calculations, such as micropile design calculation and pile length optimization for the project, was completed. The results show that the miniature pile length optimization model based on numerical simulation finite difference method improves the previous method by automating the optimization process through fast modeling, automatic creation of optimization commands, and output and analysis of optimization results, and realizes the optimization of pile length using numerical simulation, which improves the efficiency of the optimization of the pile length under the premise of guaranteeing accuracy, and achieves the unity of both efficiency and accuracy. The feasibility of this optimization process is proved by engineering examples. The engineering practicability of the micropile design calculation method and optimization method proposed in this study is proved through practice. It provides a reference value for the initial fast and flexible management of small landslides.

Studi Efektivitas Penambahan Bubuk Wortel dan Air Tebu Terhadap Kuat Tekan Beton Guna Mengurangi Dampak Pemanasan Global Akibat Produksi Semen

Cement production which continues to increase along with the high demand for concrete will greatly affect the global warming phenomenon. This is the background for specific research. As far as the literature review has been carried out, there have been findings in the form of carrots and sugar cane, but publications regarding this matter have not been very detailed, they are still carried out in the form of reports, both text and video. Therefore, there is a subjective thought that there is probably something that is still missing in the research. In view of this, the current research aims to determine the relationship between carrots and sugarcane juice in a concrete mixture on its compressive strength. Carrots are processed into powder without chemical additives and the sugar cane is extracted from pure water. The research was carried out on the basis of SNI and regulations that are still in effect with the number of test objects as many as 20 cylinders. In the end, the research facts show that the mix design calculation method by finding the average result of the three SNIs is not correct, because the 2 normal concrete test objects made did not reach the planned value. In addition, from the slump value test, it was found that there was only one and no modified concrete in accordance with the planned value. The results of the value of the compressive strength of concrete produced by all types of concrete specimens are that they do not exceed the planned compressive strength, which is 300 kg/m2.

Evaluation of the load-bearing wall design of Edirne Old Harbiye Barracks according to the Turkish Building Earthquake Code (TBEC-2018)

The masonry construction system consists of stone, brick, and mortar, in which the wall element acts as the vertical load load-bearing and generally allows low-rise buildings. The buildings built with this system are mostly seen in rural areas today, but also in traditional and historical textures in city centers. Stone, brick, mortar, etc. used in the masonry construction system. The materials are materials with a low stretching rate but are resistant to pressure. In this case, against the driving force of a possible horizontal load source, the bearing walls will inevitably be damaged because they do not allow sufficient oscillation. In Türkiye, earthquake-resistant building design principles and calculation methods related to the behavior of masonry structures against earthquakes are guiding at this point. Inspecting the masonry structures planned and built in the past in terms of compliance with today's conditions and regulations is important for the sustainability of the structure. Making a building that has a negative profile in terms of compliance with the masonry construction rules is important for both the structure and the health of the user. In this study, the compliance of the load-bearing walls in the architectural design of the old Harbiye Barracks building, which is currently used by the Faculty of Architecture of Trakya University, to the rules regarding the wall design in the current regulation, Türkiye Building Earthquake Code 2018, is investigated. As a result of the study, it was seen that the building showed different suitability in different blocks. While the occupancy-to-space ratio of the b block on the bearing wall is better, it has been determined that the block does not fully comply with the rules.

Transmission Shaft Performance Using Static Simulation for Brushing Simulator

The brushing simulator assists researchers and dentists in conducting investigations on human teeth and plaque removal. In this paper, the development of a brushing simulator is studied. Which focuses on the life expectancy of shaft material used in the development process in the future. The aim of this study is to analyse the stress distribution of the aluminium and brushing simulator’s stainless steel threaded shafts. Besides, to analyse the brushing simulator’s threaded shaft life expectancy. The motor speed of Set 1 can be modified to 450 rpm, 480 rpm, 510 rpm, or 540 rpm. Meanwhile, speeds for set 2 are 550 rpm, 580 rpm, 610 rpm, and 640 rpm. In this study, Solidworks software was used to construct a brushing simulator model and obtain the result of stress distribution in a static simulation. The life expectancy of the aluminium and stainless-steel threaded shafts was determined from the design calculation method by using the simulation data. The threaded shaft life expectancy result showed that stainless steel is more durable than aluminium which is 3522 hours from set 1 compared to 728 hours at 640 rpm for the aluminium threaded shaft. Based on its material properties, the findings indicate that stainless steel is stronger than aluminium. Furthermore, the study shows that life expectancy at speeds below 550 rpm is higher than at speeds above 550 rpm. Hence, the life expectancy of a threaded shaft decreases as the speed increases.

Study on Fundamental Force of Extreme Wave on Complex Deepwater Jacket

With the development of offshore wind power to the far-reaching sea, jacket foundation suitable for 10 ~ 60m water depth has become a development trend. The maximum waves in the far-reaching sea are generated by typhoons. The South China Sea spans the tropics and subtropics. Tropical cyclones therein are extremely active due to the features of its marine environment, like wide water-depth profile, complex topography and hydrology. Especially in recent years, under the development situation of global warming, extreme weather events have increased significantly, and strong and super typhoons have become more frequent. The extreme waves generated by them have a huge force on the jacket, affecting the safety of the project. In this paper, the relevant parameters of PMTC are calculated with the statistical method, the verified SWAN model is used to calculate the probable maximum typhoon wave, and the P-III frequency analysis on the extrapolated results of all typhoon waves are carried out by direction to obtain the design wave elements of each return period, and various extreme typhoon wave characteristic parameters were counted. Secondly, the Morison formula is used to calculate the wave force acting on the offshore fan jacket. This wave force based on different water depth and different directions is tested by physical model test. Finally, the results of model test and theoretical calculation are compared and analyzed to confirm that there is a certain correlation between the two wave forces. This empirical formula can be used to correct the calculated value of Morison formula in practical engineering design, which not only provides a simple and convenient calculation method for practical engineering design, but also provides a reference for the calculation model of the total force generalization of deep-sea complex structure foundation, which has certain theoretical value and practical significance.