Analysis on Regional Power Grid Load Characteristics and Rational Allocation of Capacity Load Ratio

The reasonability of the adopted capacity load ratio numerical value in urban power grid planning determines the economy of planning level yearly power grid.Too large capacity load ratio will result in the increasing investment in the early period of power grid construction, however, too small capacity load ratio will make the power grid have poor adaptability, affecting the power supply. Reasonably determining the adopted regional power grid capacity load ratio quantitative numerical value in planning has a strong guiding significance for constructing reliable and economic power grid and preventing power grid from excessive advance or lagging behind the load development. This paper, through the statistics and analysis of a certain regional power grid 2010-2012 three years＇ power grid daily load characteristics and the investment benefit evaluation of three years＇ 220KV power grid individual project, makes a preliminary analysis and puts forwards the specific advice on the reasonable values of power ~rid 35-220KV power transformation capacity load ratio.

Optimal Design of the Modular Joint Drive Train for Enhancing Cobot Load Capacity and Dynamic Performance

Automation advancements prompts the extensive integration of collaborative robot(cobot)across a range of industries.Compared to the commonly used design approach of increasing the payload-to-weight ratio of cobot to enhance load capacity,equal attention should be paid to the dynamic response characteristics of cobot during the design process to make the cobot more flexible.In this paper,a new method for designing the drive train parameters of cobot is proposed.Firstly,based on the analysis of factors influencing the load capacity and dynamic response characteristics,design criteria for both aspects are established for cobot with all optimization design criteria normalized within the design domain.Secondly,with the cobot in the horizontal pose,the motor design scheme is discretized and it takes the joint motor diameter and gearbox speed ratio as optimization design variables.Finally,all the discrete values of the optimization objectives are obtained through the enumeration method and the Pareto front is used to select the optimal solution through multi-objective optimization.Base on the cobot design method proposed in this paper,a six-axis cobot is designed and compared with the commercial cobot.The result shows that the load capacity of the designed cobot in this paper reaches 8.4 kg,surpassing the 5 kg load capacity commercial cobot which is used as a benchmark.The minimum resonance frequency of the joints is 42.70 Hz.

SIMPLIFIED ANALYSIS METHOD FOR ULTIMATE LOAD CAPACITY OF WEB PLATES OF BOX GIRDERS

The prosperous post buckling load capacity of web plates of box girders can be used.In this article,the post buckling behaviour of web plates of box girders under different loading conditions is theoretically analyzed and on the basis of domestic and overseas design codes of steel structures,the corresponding simplified analysis methods are put forward for the engineering design or code revision.It is proved that the simplified methods are safe,efficient and practicable through the comparison between several results.

Load Bearing Capacity and Safety Analysis for Strain-hardening Austenitic Stainless Steel Pressure Vessels

By increasing the yield strengths of austenitic stainless steels for pressure vessels with strain hardening techniques,the elastic load bearing capacity of austenitic stainless steel pressure vessels can be significantly improved.Two kinds of strain hardening methods are often used for austenitic stainless steel pressure vessels：Avesta model for ambient temperature applications and Ardeform model for cryogenic temperature applications.Both methods are obtained from conventional design rules based on the linear elastic theory,and only consider the hardening effect from materials.Consequently this limits the applications of strain hardening techniques for austenitic stainless steel pressure vessels because of safety concerns.This paper investigates the effect of strain hardening on the load bearing capacity of austenitic stainless steel pressure vessels under large deformation,based on the elastic-plastic theory.Firstly,to understand the effect of strain hardening on material behavior,the plastic instability loads of a round tensile bar specimen are derived under two different loading paths and validated by experiments.Secondly,to investigate the effect of strain hardening on pressure vessels strength, the plastic instability pressure under strain hardening is derived and further validated by finite element simulations.Further,the safety margin of pressure vessels after strain hardening is analyzed by comparing the safety factor values calculated from bursting tests,finite element analyses,and standards.The researching results show that the load bearing capacity of pressure vessels at ambient temperature is independent of the loading history when the effects of both material strain hardening and structural deformation are considered.Finite element simulations and bursting tests results show that the minimum safety factor of austenitic stainless steel pressure vessels with 5% strain hardening is close to the recommended value for common pressure vessels specified in the European pressure vessel standard.The proposed study also shows that in the strain hardening design of austenitic stainless steel pressure vessels,the calculation for plastic instability pressure could use theoretical formula or finite element analyses based on geometrical dimensions and material property parameters before strain hardening,but a 5%strain should be employed as a design limit.The proposed research can be used for the strain hardening design of austenitic stainless steel pressure vessels safely.

Influence of Particles on the Loading Capacity and the Temperature Rise of Water Film in Ultra-high Speed Hybrid Bearing

Ultra-high speed machining technology enables high efficiency, high precision and high integrity of machined surface. Previous researches of hybrid bearing rarely consider influences of solid particles in lubricant and ultra-high speed of hybrid bearing, which cannot be ignored under the high speed and micro-space conditions of ultra-high speed water-lubricated hybrid bearing. Considering the impact of solid particles in lubricant, turbulence and temperature viscosity effects of lubricant, the influences of particles on pressure distribution, loading capacity and the temperature rise of the lubricant film with four-step-cavity ultra-high speed water-lubricated hybrid bearing are presented in the paper. The results show that loading capacity of the hybrid bearing can be affected by changing the viscosity of the lubricant, and large particles can improve the bearing loading capacity higher. The impact of water film temperature rise produced by solid particles in lubricant is related with particle diameter and minimum film thickness. Compared with the soft particles, hard particles cause the more increasing of water film temperature rise and loading capacity. When the speed of hybrid bearing increases, the impact of solid particles on hybrid bearing becomes increasingly apparent, especially for ultra-high speed water-lubricated hybrid bearing. This research presents influences of solid particles on the loading capacity and the temperature rise of water film in ultra-high speed hybrid bearings, the research conclusions provide a new method to evaluate the influence of solid particles in lubricant of ultra-high speed water-lubricated hybrid bearing, which is important to performance calculation of ultra-high speed hybrid bearings, design of filtration system, and safe operation of ultra-high speed hybrid bearings.

Ultimate Load Capacity and Reinforcement of Circular-Hollow-Section N-Joint

Experimental research and numerical analysis were applied to study the ultimate load capacity(ULC) and reinforcement of circular-hollow-section N-joint.Four specimens were tested under static load.The ULC of each specimen was obtained and the detailed failure conditions were discussed.Based on the results, both welding a plate on the chord member and filling concrete in the chord member are effective to reinforce the N-joint, but it is suggested that these two methods should not be applied simultaneously.Mo...

Prediction of Load Carrying Capacity of Corroded Reinforced Concrete Beam

A novel method for prediction of the load carrying capacity of a corroded reinforced concrete beam (CRCB) is presented in the paper. Nine reinforced concrete beams, which had been working in an aggressive environment for more than 10 years, were tested in the laboratory. Comprehensive tests, including flexural test, strength test for corroded concrete and rusty rebar, and pullout test for bond strength between concrete and rebar, were conducted. ne flexural test results of CRCBs reveal that the distribution of surface cracks on the beams shows a fractal behavior. The relationship between the fractal dimensions and mechanical properties of CRCBs is then studied. A prediction model based on artificial neural network (ANN) is established by the use of the fractal dimension as the corrosion index, together with the basic information of the beam. The validity of the prediction model is demonstrated through the experimental data, and satisfactory results are achieved.

Non-capacity transport of non-uniform bed load sediment in alluvial rivers

Rivers often witness non-uniform bed load sedim ent transport. For a long tim e, non-uniform bed load transport has been assum ed to be at capacity regime determined exclusively by local flow. Yet whether the capacity assumption for non-uniform bed load transport is justified remains poorly understood. Here, the relative time scale of non-uniform bed load transport is evaluated and non-capacity and capacity models are compared for both aggradation and degradation cases with observed data. As characterized by its relative time scale, the adaptation of non-uniform bed load to capacity regime should be fulfilled quickly. However, changes in the flow and sedim ent inputs from upstream or tributaries hinder the adaptation. Also, the adaptation to capacity regime is size dependent, the finer the sediment size the slower the adaptation is, and vice versa. It is shown that the capacity model may entail considerable errors compared to the non-capacity model. For modelling of non-uniform bed load, non-capacity modelling is recommended, in which the temporal and spatial scales required for adaptation are explicitly appreciated.

Ultimate Load Capacity of Offshore Pipeline with Arbitrary Shape Corrosion Defects

A set of generalized solutions are proposed for estimating ultimate load capacity of pipeline with arbitrary corrosion shapes subjected to combined internal pressure, axial force and bending moment. Isotropic and anisotropic material characteristics in longitudinal and circumferential direction of pipeline are also considered in the proposed equations. Simplified numerical method is used to solve the generalized expressions. The comparisons of numerical results based generalized solutions and full-scale experimental results are carried out. The predicted results agree reasonably well with the experiment results. Meanwhile, the effects of corrosion shapes and locations on the ultimate load capacity are studied.

Determination of the load bearing capacity of pre-stressed expandable props for ground support in underground mines

This paper aims to determine the load bearing capacity of pre-stressed expandable props with different geometries and load eccentricities for flexible support in underground mining or excavation.It is deduced that the expandable device could have much higher strength(>89 MPa)by laboratory tests,and the load bearing capacity of the expandable prop may depend on the stability of the supporting steel pipe structure.A good agreement was found between the laboratory test and numerical results in terms of the load bearing capacity and the final macro-bending failure pattern for expandable props with heights of 1.5 and 2.7 m,and the theoretical calculation for the strength of traditional steel structures is not directly suitable for the expandable props.Moreover,additional numerical simulations were performed for the expandable props with different normalized slenderness ratiosλ_(n)and loading eccentric distances e.The variation of stability coefficient of the expandable prop is in line with the Perry-Robertson equation and its correlation coefficients are fitted as a of 0.979 and b of 0.314.For estimating the load bearing capacity of the expandable props,the strength equation for traditional steel structures is improved by introducing a bending magnification factor and by modifying the normalized slenderness ratio to a converted slenderness ratio.Based on the underground field monitoring for the strength of expandable props with different heights,the empirical eccentric distances were back calculated,and a safety factor is introduced to obtain the designed strength of the expandable prop.In addition,a four-step design procedure is proposed for the expandable prop.

A new calculation method for axial load capacity of separated concrete-filled steel tubes based on limit equilibrium theory

A new calculation method for axial load capacity of separated concrete-filled steel tubes based on limit equilibrium theory was proposed,which took into account the decrease of confinement effect by steel tube and the non-uniform distribution of ultimate stress in cored concrete.The accuracy of the analytical result is validated through running the numerical result by finite element method (FEM) and experimental data as well.The influences of the key parameters on the load capacity of the concrete-filled steel tube (CFST) was studied,including the separation ratio,concrete compressive strength,and steel strength.The results indicate that the load capacity of the tube increases with concrete strength and steel strength under the separation ratio less than 4%,while decreases with a higher separation ratio improved.

Load-Bearing Capacity of the Footing Resting on a Reinforced Fly Ash Slope

In several parts of the world, disposal of waste materials such as fly ash is a great problem. Application of waste materials as structural fills in foundations is one of the best solutions to disposal problems, because wastes can be used in large volumes in such applications. There may be difficulty due to poor load-bearing capacity of fly ash, especially when footing rests on the top of the fly ash fill slope. Inclusion of polymeric reinforcements as horizontal sheets within the fill may be one of the most viable solutions to improving the load-bearing capacity of reinforced fly ash slope, and it is particularly important for the situations where foundations need to be located either on the top of a slope or on slope itself. The present work is aimed at investigating the efficacy of a single layer of reinforcement in improving the lo, ad-bearing capacity when it gets incorporated within the body of a model fly ash embankment slope. An increase in load bearing capacity due to the incorporation of reinforcement in the model slope was found by conducting laboratory tests. Experimental results were compared by numerical values obtained using software GEO5 and PLAXIS.

Analysis of Pollutant Load Carrying Capacity of the River Tapi Using QUAL2Kw for Surat City

River Tapi is the prime water body for Surat city, Gujarat, India. On a long stretch of 22.39 km in Surat city (Kamrej to Causeway) of the Tapi river, there are many identified and non-identified discharge points available. Excessive discharge from these points restricts the efficiency of the self-purification process which ultimately degrades the river water quality. In this paper, an attempt has been made to estimate the pollutant load-carrying capacity at different segments of the river Tapi using the QUAL2Kw tool. The study has been undertaken with different scenarios: First, the QUAL2Kw model was trained with available river water quality and hydraulic data of the Tapi river in which the complete river segment was divided into 21 reaches. The model was calibrated and validated with the actual concentrations of the pollutants entering. In the second phase, all the point source, non-point source, and headwater characteristics were considered and the pollutant load-carrying capacity of the river in terms of BOD, ISS, and N-nitrate was found. In the third phase, all the sources of pollutants entering the river have been removed and only headwater characteristics were considered for the study. The results indicate that reach no. 21 (21.23ºN, 72.82ºE) has the maximum load-carrying capacity of Biochemical Oxygen Demand (BOD) up to 2057.7 kg/day, Inorganic Suspended Solids (ISS) up to 85633.8 kg/day, and Nitrate (NO3) up to 31688.8 kg/day. However, reach no. 4 has the minimum load carrying capacity of BOD up to 1088.1 kg/day, reach 8 carries a minimum of ISS 205341.6 kg/day and NO3 10215.57 kg/day.

NEW APPROACHES FOR COMPUTING DYNAMIC LOAD-CARRYING CAPACITY OF MULTIPLE COOPERATING ROBOTIC MANIPULATORS

A novel unified method for computing the dynamic load carrying capacity(DLCC) of multiple cooperating robotic manipulators is developed.In this method,the kinematic constraints and the governing dynamic equations of the multiple robot system are formulated in the joint space by using the method of transference of dependence from one set of generalized coordinates to another,and the virtual work principle,which includes the readily available dynamics and joint torques of individual manipulators,and the dynamic of payload.Based on this dynamic model,the upper limit of the DLCC at any points on a given trajectory is obtained by solving a small size linear programming problem.This method is conceptually straightforward,and it is applicable also to the cases of multi fingered robot hands and multi legged walking machines.

Experimental investigation of axially loaded steel fiber reinforced high strength concrete-filled steel tube columns

An experimental study on the compressive behavior of steel fiber reinforced concrete-filled steel tube columns is presented. Specimens were tested to investigate the effects of the concrete strength, the thickness of steel tube and the steel fiber volume fraction on the ultimate strength and the ductility. The experimental results indicate that the addition of steel fibers in concrete can significantly improve the ductility and the energy dissipation capacity of the concrete-filled steel tube columns and delay the local buckling of the steel tube, but has no obvious effect on the failure mode. It has also been found that the addition of steel fibers is a more effective method than using thicker steel tube in enhancing the ductility, and more advantageous in the case of higher strength concrete. An analytical model to estimate the load capacity is proposed for steel tube columns filled with both plain concrete and steel fiber reinforced concrete. The predicted results are in good agreement with the experimental ones obtained in this work and literatures.

Preparation and Crystal Modification of Ibuprofen-Loaded Solid Lipid Microparticles

An emulsion-congealing technique is used to prepare solid lipid microparticles （SLM） containing ibuprofen with glyceryl behenate, tripalmitin and beewax as excipients. The difference of the solubility parameters between the excipients and ibuprofen are used to analyze their compatibility. Both the solubility parameter analysis and the experimental results show that glyceryl behenate is the best among the three excipients. The solid particles disperse well in aqueous phase when the drug loading reaches 10% （relative to lipid only）. Glycerides exhibit marked polymorphism and their rapid rates of crystallization accelerate the formation of metastable crystal modification. The metastable crystal modification characterizes high drug loading capacity but less stability. Increasing the content of lipophilic drug in a lipid matrix facilitates the transformation of excipients to more stable polymorphic forms.

Parametric analysis of thermal effect on hydrostatic slipper bearing capacity of axial piston pump

Hydrostatic slipper was often used in friction bearing design, allowing improvement of the latter's dynamic behavior. The influence of thermal effect on hydrostatic slipper bearing capacity of axial piston pump was investigated. A set of lumped parameter mathematical models were developed based on energy conservation law of slipper/ swash plate pair. The results show that thermal equilibrium clearance due to solid thermal deformation periodically changes with shaft rotational angle. The slipper bearing capacity increases dramatically with decreasing thermal equilibrium clearance. In order to improve the slipper bearing capacity, length-to-diameter ratio of fixed damper varies from 3.5 to 8.75 and radius ratio of slipper varies from 1.5 to 2.0. In addition, the higher slipper thermal conductivity is useful to improve slipper bearing capability, but the thermal equilibrium clearance is not compromised.

Investigating the Efficiency Coefficient of Pile Group in Clay Under Two-Way Lateral Load

This research investigates the behavior of a 2×2 pile group under two-directional lateral loads in addition to the vertical load.Through three-dimensional numerical modeling based on Flac 3D software,the study examines the total bearing capacity and efficiency coefficient of the pile group,considering factors such as the angle of lateral load,relative pile spacing,and relative stiffness of the pile-soil system.The findings highlight the significance of these factors in understanding and predicting the response of pile groups to changing lateral load directions.The results reveal that increasing the angle of the lateral load from 0°to 45°enhances both the maximum total lateral load and the efficiency coefficient of the pile group.When the relative stiffness of the pile-soil system significantly increases,soil stiffening occurs and reducing the relative spacing of the piles from 7 to 3 times the diameter of the piles diminishes the influence of the pile group.Consequently,the response of the pile group to lateral loads becomes more linear,with only a slight alteration in the maximum total lateral load and the efficiency coefficient when the lateral load is angled from 0°to 45°.Conversely,increasing the relative distance between the piles,specifically from 3 to 7 times the diameter of the piles,amplifies the influence of the pile group.Both the maximum total lateral load and the efficiency coefficient of the pile group exhibit an observed increase.These provide insights for designing pile groups and optimizing their performance under lateral loading conditions.

A Reliable Method of Pile Load Test on Cast-in-Situ Pile Group of Existing Building for Retrofitting

Following the foundation failure of a building, with an aim of economical solution to strengthen other existing buildings of the same project, a new arrangement was implemented experimentally to test the adequacy of load bearing capacity of a few selected cast-in-situ RCC （reinforced cement concrete） pile groups without demolishing the existing buildings. In this test, the column bottom of an existing building was removed by the help of scaffolding and after that a frame system consisting tension piles and hollow beam was constructed over the pile cap of the to be tested pile group. The load was tested by the help of hydraulic jack system and the constructed frame system. This paper contains the detailed plan, arrangement and method of the test with illustrations. The deflection and loading data analysis is also included which was performed to determine the outcome of the test. Through this test method the appropriate assessment of capacity of pile group of existing building could be done successfully and in result the structure could be saved by only super structure retrofitting.