A unified optimization design method for multi-stage non-circular gear transmission based on periodic B-spline interpolation

Continuously variable transmission (CVT) of noncircular gear has the technical advantages of large bearing capacity and high transmission efficiency. The key technology of CVT with noncircular gear has been broken through some countries, and is in the stage of deep application research. Although the characteristics and design methods of noncircular gear pairs have been continuously studied in China, the noncircular gear CVT is still in the preliminary exploration and research stage. The linear functional noncircular gear pair, whose transmission ratio is a linear function in the working section, to realize continuously variable transmission was the research object in this paper. According to the required transmission ratio in the working section, the transmission ratio function in the non-working section was constructed by using a polynomial. And then the influence of pitch curve parameters in the working section on which in the non-working section was also analyzed to obtain the pitch curve suitable for transmission of this gear pair. In addition, for improving the stability and bearing capacity of gear transmission, the noncircular gear pair transmission with high contact ratio was designed. Furthermore, the accurate value of the contact tooth length was calculated based on the gear principle and the characteristics of the involute tooth profile, from this the contact tooth length error was calculated by comparing the accurate value with its actual value obtained by the rolling experiment. Finally, an indirect method to verify the contact ratio by detecting the contact length error of the tooth profile was proposed.

Flexural retrofitting of reinforced concrete (RC) beams using fiber-reinforced polymer (FRP) plate is a common way to increase the flexural capacity. There is a lack of rational design method to determine where the strengthening plate can safely be curtailed. As a result, retrofitted beams commonly fail by debonding of the FRP plate, which occurs well before the target flexural capacity. Debonding is brittle failure; thus, ductility of the retrofitted beam needs to be ensured by debonding prevention. With sufficient ductility the ultimate strength can continuously increase beyond steel yields with the elastic behavior of the FRP strengthening plate. Debonding prevention has been accounted for empirically in most design approaches so far. The global energy balance approach (GEBA) using fracture mechanics has been proposed to determine the debonding load of an FRP-RC beam that is affected by the plate curtailment location. The GEBA results for various FRP-RC beams can be summarized using debonding contours on plots of moment capacity against the safe plate curtailment locations. The debonding contours constructed in this way for the beams with the same ratio of depth to fracture energy are virtually the same. This paper shows how GEBA can be incorporated into the design process to prevent premature debonding of the FRP plate. The method makes use of the debonding contours and derives from these simplified design charts that could be made available to designers. The retrofitting design consideration and the theoretical background of this unified design method are first explained, followed by the derivation of the conceptual design charts. Numerically correct design charts are then constructed for a wide range of design cases. Finally, a worked example is used to explain the way to apply the unified design method using design charts.

Prevention of resonance oscillations in gear mechanisms using non-circular gears

More and more planetary gear mechanisms are being used in Hybrid Electric Vehicle (HEV) as multi-energy coupling mechanisms because of their compact structure, high transmission efficiency and strong load bearing capacity. In order to get all the planetary gear schemes that satisfy the requirements of topological characteristics and select the optimal scheme for Hybrid Electric Vehicle Planetary Gear Coupling Mechanism (HEV-PGCM) as the references for the following analysis and structure design. Firstly, a variety of HEV-PGCM schemes with required topological characteristics are designed by applying the Creative Design Method. Secondly, according to the design requirements of planetary gear transmission and HEV power coupling mechanism, combined with Matrix Theory, the scheme evaluating indicators and method for HEV-PGCM are presented and used for scheme analysis and optimal selection. The results indicate that this method is general for common use and it can provide reference schemes for the following structure parameter design and analysis of HEV-PGCM.

Applying the non-circular gear to transplanting mechanism can get more desirable planting work locus, which is a hot research topic recently. Pascal curve gear was obtained by researching features of Pascal curve in this paper, the non-circular gear planetary transplanting mechanism was designed using Pascal curve gear. Mathematical modeling of the various gears was carried out. Software for dynamic simulation and parameter optimization of non-circular gear transplanting mechanism was developed. Using the software, users input a set of parameters, and the software instantly calculates and shows the work locus and motion simulation, then users can judge whether the parameters are reasonable and get the appropriate planting work locus, validating that Pascal curve gear can be used in rice transplanter. Optimization parameters obtained from software are of guiding significance for the manufacture and testing of physical prototypes.

Propeller design diagrams, like Bp-δ diagram, are widely applied in ship propeller design. However, different propeller series use various selection approaches, so comparisons between designs are only possible after individual candidates are chosen.This paper proposes a unified approach based on machine learning to allow efficient comparison and facilitate the selection of the optimal propeller amongst the available propeller series. The process starts by compiling propeller series data to generate a comprehensive dataset on propeller performance. This dataset is then used to train an Artificial Neural Network (ANN) model, which accurately predicts open-water propeller performance. Optimization techniques are applied to maximize propeller efficiency based on the specific needs of the vessel, while ensuring compliance with cavitation and noise constraints for safety. The model's accuracy is validated using data from the KRISO Container Ship (KCS), demonstrating the prediction's reliability. The method is then applied to select both open and ducted propellers for a variety of ship types to meet specific operational requirements. Ultimately, the optimized results are ranked by efficiency, offering an organized set of options for selecting the most suitable propeller. This approach eliminates the need for manual dataset correlation, significantly improving the efficacy of generating an outperforming initial design.

Stability property is the key index for converter control. A practical stable control scheme is proposed for DC power supply converters. Firstly, the converter system is described as a linear model with two constraints, one is that the input is discontinuous and it is a Finite Control Set (FCS), the other is that the switching frequency is limited. Secondly, a unified control design method satisfied the constraints to guarantee the practical stability and convergence called sampling point equivalence scheme is introduced, which is illustrated as the duty cycle feedback control in form. Then the relationship between the convergent zone and the sampling time is analyzed, which is also the character of practical stability. The DC-DC buck converter is chosen as the plant to show the proposed methods, which are finally validated by both simulation and experiments.

Sandy soils may undergo compression during liquefaction. A review of published design manuals, including the 2004 AASHTO LRFD Bridge Design Specifications, indicates that some recommendations for pile design may not represent the pile response in a manner consistent with the actual axial response of the pile during liquefaction. The actual response is discussed in light of the unified pile design method and separated between liquefaction occurring above and below the static nonliquefied neutral plane location before the liquefaction event. In the former case, the effect on the pile is minor regardless of the magnitude of liquefaction-induced settlement of the surrounding soil. In the latter case, the axial compressive load in the pile increases and additional pile settlement (downdrag) will occur when the force equilibrium is reestablished through the necessary mobilization of additional toe resistance. This means that the magnitude of the downdrag is governed by the pile toe load-movement response to the downward shift of the neutral plane. While there is a reduction in shaft resistance due to the reduction in strength within the liquefied layers, this reduction will only influence the pile design length where the liquefying layer is very thick.

Code-based design of piles with negative skin friction (NSF) considers the NSF force (the drag force) as a load to be imposed on the pile as an unfavourable design action. These codes – for example Singapore Code of Practice CP4, UK Standard BS EN 8004:1986 and the recent Eurocode 7 (EC7) (BS EN 1997-1:2004) – would indirectly factor up the value of the drag force while at the same time disregard the shaft resistance above the neutral plane and factor down the positive shaft resistance below the neutral plane. Thus, the pile design in very deep soft clays typical of Singapore and Asian coastal plains will lead to very conservative pile lengths to meet the code requirements. The Fellenius unified pile design method recognised this deficiency, and it allows for better pile design with NSF taking into account the need for both force and settlement equilibrium between the pile and the soil. Fortunately, EC7 also allows for interactive pile–soil analysis using modern finite-element method tools that can optimise pile design for NSF, in particular when the remaining consolidation settlements around the piles are relatively small. This paper will compare these methods, provide insights into the proper understanding of NSF effects on pile behaviour and recommend the way forward for rational and economical pile design in settling soils.

Various process models have been proposed for system development, which represent all stages from requirements analysis to implementations and tests. However, these process models focus not on improvement of the model of the system itself but on the development of processes to adapt to the properties of the requirements in system development. First, we arranged the features of system development. Then, we modeled the requirements and a system, and propose here a design method by which the customer and designer can always check requirements by introducing not plural design methods using various conventional design model figures but a unified multiphase design method, even if the designer does not implement the system. The customer and designer can check the requirements using the animations of the scenarios described as requirements. Finally, we present an example of execution, which designs a system using the proposed model, and describe avenues for future work.

Comparison of Cost of Reinforced Concrete Frame Buildings Designed Using IS Code and Unified Performance-Based Design Method

Strain limits vs. reinforcement ratio limits – A collection of new and old formulas for the design of reinforced concrete sections

This is a very brief chapter outlining the design method to be used for the remainder of this part of the book. As you will see it is an amalgam of the use case analysis phase of Objectory, the methodology of OMT and the UML notation. This is because such a combination represents current best practice in the software industry. It also indicates the way in which the unified design method is itself developing.KeywordsUnify Modeling LanguageClass DiagramCase ModelSequence DiagramObject Management GroupThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

The profile of the pitch curve of external and internal noncircular gears, and the restricting conditions to avoid the interferences were analyzed, and the designing conditions of the mechanisms were decided. Then, the noncircular planetary gear mechanisms were synthesized as intermittent motion mechanisms, and the noncircular gear shaper was made by way of experiment and gears were cut. And then, the mechanisms were produced and the static characteristic was investigated.

PurposeThe purpose of this paper is to minimize the volume of straight bevel gear and to develop resistance towards scoring failure in the straight bevel gear. Two evolutionary and more advance optimization techniques were used for performing optimization of straight bevel gears, which will also save computational time and will be less computationally expensive compared to a previously used optimization for design optimization of straight bevel gear.Design/methodology/approachThe following two different cases are considered for the study: the first mathematical model similar to that used earlier and without any modification to show efficiency of the optimization algorithm for straight bevel gear design optimization and the second mathematical model consist of constraints on scoring and contact ratio along with other generally used design constraints. Real coded genetic algorithm (RCGA) and accelerated particle swarm optimization (APSO) are used to optimize the straight bevel gear design. The effectiveness of the algorithms used has been validated by comparing the obtained results with previously published results.FindingsIt has been found that APSO and RCGA outperform other algorithms for straight bevel gear design. Optimized design values have reduced the scoring effect significantly. The values of the contact ratio obtained further enhances the meshing operation of the bevel gear drive by making it smoother and quieter.Originality/valueLow volume is one of the essential requirements of gearing applications. Scoring is a critical gear failure aspect that leads to the broken tooth in both high speed and low-speed applications of gears. The occurrence of scoring is hard to detect early and analyse. Scoring failure and contact ratio have been introduced as design constraints in the mathematical model. So, the mathematical model demonstrated in this paper minimizes the volume of the straight bevel gear drive, which has been very less attempted in previous studies, with scoring and contact ratio as some of the important design constraints, which the objective function has been subjected to. Also, two advanced and evolutionary optimization algorithms have been used to implement the mathematical model to reduce the computational time required to attain the optimal solution.