Calculation Method Of Strength Research Articles

Finite Element Analysis on the Steel Transmission Pole

At present, the finite element method is used to calculate the strength and deformation of the steel transmission pole less. Using ANSYS to model steel transmission pole, loading, analysis, the results show that, the traditional method of strength calculation and finite element analysis results are very close, the traditional method of deformation calculation and finite element analysis results has a certain bias. As long as the establishment of three-dimensional model of the steel transmission pole, the applied load and boundary conditions to meet the actual, finite element analysis can provide a more reliable basis for the design and verification of the steel transmission pole.

Analysis of Hybrid Effect of Two Hybrid Fiber CGFRP Bar and its Mechanical Properties

Using two or more different fiber mixed form high-powered composite reinforcement, through the control of the amount of fiber bundles, to "hybrid excellent", can not only ensure the tensile strength, and can effectively improve the toughness of the FRP bar . The paper based on the theory of the composite material hybrid effect of carbon fiber and glass fiber hybrid form the CGFRP bar hybrid mode, mixed ratio, hybrid effect analysis and research, this paper expounds the influence of the main factors CGFRP bar ductility, puts forward the CGFRP bar effect positive hybrid fiber critical size, stress-strain curve, tensile strength and elastic modulus calculation method, ensure the use of performance under the premise, and put forward the CGFRP bar design idea of reinforced concrete structure FRP ductility design, improve the safety of the structure provides an effective way.

Practical aspects of development of standards for calculating strength of vessels and apparatuses

The viewpoint of one of the developers of the collection of national standards GOST R 52857.1–2007 – GOST R 52857.12–2007 “Vessels and Apparatuses. Norms and Methods of Strength Calculation” on the problems of support for standards over their life cycle is elucidated and recommendations are offered on the definition of some basic terms used in the normative documents.

Model Test Investigation on a J-Lay System Designed for Deepwater Pipeline Installation in South China Sea

A J-lay crane barge named Double-8000, the two cranes of which have the lifting capacity of up to 8000t, is about to be constructed by Offshore Oil Engineering Co., Ltd. (COOEC) in order to meet the requirements of oil and gas development in South China Sea. This paper presents the overall structure design of the J-lay system and corresponding method for strength calculation. The hardware and software for the J-lay control system are also developed. The model test on such a designed J-lay system along with its control system is investigated by applying the similarity theory and the hybrid model test method. A specially designed platform simulating the motion of the crane barge in 6 degree-of-freedom (6-DOF) in different sea conditions is used for the model testing in order to get the results of the influence of the crane motion on the performance of the J-lay system. The model tests verify the functionality and safety performance of the system. The results show that the test data are in good agreement with the numerical simulation. It can be seen that the J-lay system can meet the challenging requirements of Double-8000 for pipeline laying in waters deep to 3000m in South China Sea.

Experimental Study of Loess Structural Strength and Resistance Coefficient

The paper proposes a calculation method of soil particles framework structural strength, and provides a new parameter, defined as resistance coefficient, which can quantitatively describe the relationship between active stress and passive stress on soil particles framework. The research of the impact of water content, binding materials content and dry density on structural strength and resistance coefficient is conducted under confined compression test with undisturbed and man-made cement structural loess from Yangling. The research shows that structural strength of loess particles framework increases with the increasing of deformation, and with the same deformation, the structural strength of loess particles framework increases with the increasing of water content ; loess particles framework is sensitive to the weakening role of water. The resistance coefficient is smaller and more instability with the increasing of deformation under high water content conditions. The binding material has significant effect on structural strength and resistance coefficient. Moderate cement mixed with loess particles framework cannot only improve the structural strength but also decrease the sensitivity of loess particles framework to the weakening role of water. By controlling the binding material content, water content and dry density, the structural strength and resistance coefficient of man-made cement structural loess will be the same as the undisturbed loess. Increasing dry density can make the structural strength of loess particles framework higher, but the value and the stability of resistance coefficient of loess particles framework structure with high dry density is lower than that in the initial dry density.

Tooth Profile Synthesis and Strength Computation of Swing Movable Teeth Drives

The tooth profile synthesis of swing movable teeth drives was performed. The tooth profile equation of the internal teeth ring was established. The analysis result shows the deformation distribution of the movable tooth in the normal direction at the contact point of the wave generator is a sine function. Furthermore, the forces of the wave generator, the movable tooth pin and the internal teeth ring acting on the movable tooth were analyzed. Based on the Hertz theory and material mechanics, the contact strength calculation methods for the meshing pairs of the movable tooth and the wave generator as well as the movable tooth and the internal teeth ring were discussed. The calculation method for the bending strength of the pin was also derived. The research result provides a theoretical basis for designing and applying swing movable teeth drives.

EFFECT OF APPLIED AXIAL FORCES ON STRUCTURAL PERFORMANCE OF CES BEAM-COLUMN JOINTS

In this study, validity of calculation method of ultimate strength of beam-column joints for composite CES structural systems, is examined using past experimental results. And three dimensional non-linear FEM analysis conducted, the effect of axial force on shear capacity of CES beam-column joint was verified. It is shown that ultimate strength of CES beam-column joints could be evaluated by a method based on the AIJ design standard for SRC structures. And different axial force didn't significantly affect shear stress condition of joints panel subjected to discrepancy in the analysis, it is found that the effect of axial force on shear capacity of CES joint panel is small.

STRENGTH CALCULATION METHOD OF TIMBER BEAM WITH TWO HOLES

Now, there are the needs of the utilization of timber structure to the non-housing buildings. It needs the several techniques without the conventional wooden structure techniques. The multi story wooden structures having long span need the technique of making large holes in the beams due to the pipe arrangement of the equipments. We, in this article, propose a manual strength calculation method of the timber with two circular holes taken into account the size effect, the hole size, the distance between the both holes, and the ratio of the bending moment and shear force as the parameters. Two failure modes was assumed, the shear failure of timber between the both holes, and the splitting fracture from the hole. From the experimental observation, the shear failure was occurred in the specimen having the short distance between the holes —less than 0.5 times of the hole diameter. And splitting fracture was occurred in the specimen having the long distance between the holes —over 0.5 times of the hole diameter. The calculation method was derived from the mechanical models based on fracture mechanics and basic beam theory. The validity of the proposed calculation method was confirmed by the experimental results whose parameters were the hole size, the size effect, and the distance between both the holes.

A proposed methodology for the design and characterisation of concrete screw anchors

In recent years the construction fixings industry has begun to look to the concrete screw anchor to alleviate lengthy installation cycles and expansion issues, whilst introducing temporary fixing capability and suitability for use in cracked concrete. The screw anchor, often used in heavy-duty structural applications, operates on a mechanical interlock principle by creating a threaded cut in the substrate. Previous research has revealed this operational principle to show similarities to both expansion and chemical anchors—the two predominant fixings systems in current construction practice. Still in its infancy, the product lacks a certified test procedure and program for attaining technical approvals. This paper describes the development of an improved methodology for analysing the performance of the concrete screw anchor both physically and theoretically. Having reviewed the current test procedures, a range of products available on the market were assessed manually in the interest of developing an understanding of product operation. Standard test approaches were then customised to suit the unique product characteristics, before continuing to gather performance data. This research work then focuses upon theoretical performance calculation. Currently two theoretical models are potentially applicable to the concrete screw anchor; the concrete capacity method and the bond strength calculation method. Through comparison of the physical test data and the two current theoretical models, realisation of partial conformity with each model pointed towards promising routes for future research and a foundation for improved design of the product.

A STRENGTH CALCULATION METHOD OF SINGLE BOLTED TIMBER JOINT LOADED PARALLEL TO THE GRAIN

We, in this article, propose a manual strength calculation method of single bolted timber joint loaded parallel to the grain. The strength calculation method takes into account the edge distance, the end distance, and the slenderness ratio as the parameters. The validity of the proposed calculation method was confirmed by the experimental results, the edge distance of 1d, 2d, 4d, 6d, 7d, the end distance of 1d, 2.5d, 4d, 7d, 10d, the slenderness ratio of 0.625d, 3.75d, 7.5d, 10d.

A STRENGTH CALCULATION METHOD OF SINGLE BOLTED TIMBER JOINT FOR END MEMBER JOINT LOADED PERPENDICULAR TO THE GRAIN

We, in this article, propose a manual strength calculation method of single bolted timber joint for end member joint loaded perpendicular to the grain. The strength calculation method takes into account the edge distance, the end distance, and the slenderness ratio as the parameters. The validity of the proposed calculation method was confirmed by the experimental results, edge distance of 1d · 2d · 4d · 6d · 7d, end distance of 1d · 2.5d · 4d · 7d · 10d, slenderness ratio of 3.75d · 7.5d · 10d.

A STRENGTH CALCULATION METHOD OF THE TIMBER WITH A CIRCULAR HOLE

The article was mainly composed of the three approaches- stress distribution by the finite element method, mechanical model based on fracture mechanics and basic beam theory, and the experiment whose parameters were size effect, the ratio of bending moment and shear force, hole size, and the arrangement of the hole. We, in this article, propose a manual strength calculation method of the timber with..circular hole taken into account the size effect, hole size, and the ratio of the bending moment and shear force as the parameters. The validity of the proposed calculation method was confirmed by the experimental results.

PRACTICAL METHOD OF FLEXURAL STRENGTH CALCULATION OF REINFORCED AND PRESTRESSED CONCRETE MEMBERS

In this paper the flexural strength analysis of reinforced and prestressed concrete members with symmetrical cross‐sections loaded in the plane of symmetry is performed. A new practical method for determining the height of the compression zone is proposed. The method is valid for normal and high‐strength concretes and for different distributions of bars along the section. It is based on the assumptions, simplifications and material properties of Eurocode 2. Design equations have been developed for the rectangular stress distribution in the concrete compression zone and for the steel stress‐strain diagrams with a horizontal and inclined top branch. A numerical example is presented to show the method usage.

Practical method of flexural strength calculation of reinforced and prestressed concrete members

Abstract In this paper the flexural strength analysis of reinforced and prestressed concrete members with symmetrical cross‐sections loaded in the plane of symmetry is performed. A new practical method for determining the height of the compression zone is proposed. The method is valid for normal and high‐strength concretes and for different distributions of bars along the section. It is based on the assumptions, simplifications and material properties of Eurocode 2. Design equations have been developed for the rectangular stress distribution in the concrete compression zone and for the steel stress‐strain diagrams with a horizontal and inclined top branch. A numerical example is presented to show the method usage.

Centrifugal load and its effects on bending strength and contact strength of a high speed thin-walled spur gear with offset web

Abstract This paper discusses effects of centrifugal load on bending strength and contact strength of a thin-walled spur gear used at high speed. A three-dimensional (3D), finite element method (FEM) is presented in this paper for analyzing centrifugal deformations and centrifugal stresses of the thin-walled gear at high speed and the responsive FEM software are developed through many years’ efforts. It is verified that the developed FEM software can calculate correct centrifugal deformations and centrifugal stresses of the thin-walled gear by a cantilever model. Then centrifugal deformations and centrifugal stresses of a thin-walled spur gear with offset web are analyzed with the FEM software at speed range 5000–40,000 rpm. It is found that effects of centrifugal load on deformations and stresses of the thin-walled gear can be neglected when gear speed is below 10,000 rpm. But it is necessary to consider the effects of centrifugal stresses on strength design of the thin-walled gear when the gear speed exceeds 10,000 rpm. Effects of the centrifugal load-deformed thin-walled spur gear on tooth contact pattern, surface contact stress, root bending stress and tooth load-sharing ratio of the gear are also investigated through performing loaded tooth contact analyses of the gear when it is engaged with a solid mating gear under a torque. It is found that centrifugal deformation of the gear at high speed has greater effects on tooth contact pattern, tooth surface contact stress, root bending stress and tooth load-sharing ratio of the pair of gears. Finally it is pointed out that strength calculation methods of a thin-walled gear are quite different from a solid gear. Methods for exact bending strength and contact strength calculations of a thin-walled gear at high speed are presented in this paper.

05/01403 A new method of strength calculation and lifetime prediction of pipe bends operating in the creep range: Webe, J. et al. International Journal of Pressure Vessels and Piping,2005, 82, (2), 77–84

A number of process reactors in refinery and petrochemical industry are constructed using low chrome alloys which are operating in the creep range and are in cyclic service. ASME B&PV Section VIII Code provides allowable stresses at elevated temperatures for design of reactor components, which are controlled by creep properties. However, fatigue design rules and fatigue exemption rules are not applicable, precluding construction of reactors using low chrome alloys at temperatures above 371 °C (7000F). ASME B&PV Section III Division 1 - Subsection NH (ASME-NH) Code considers cyclic failure modes at elevated temperatures and provides creep-fatigue interaction rules and damage limits. In this paper, creep-fatigue damage under elevated temperatures is investigated for process reactor components using elastic analysis method of ASME-NH Code for a defined representative load cycle. Also the complexities in application procedures of ASME-NH rules with thermal and structural analysis results are described in detail.

Calculation of the end-rolling strength in Q235 strip steel by the alloying electron structure parameters

Combined with the phase transformations in rolling,the phase configuration,the tensile strength,and the yield strength with different terminal rolling grain sizes in Q235strip steel have been theoretically calculated using the covalent electron number(n A )of the strongest bond in phase cells and the interface electron density difference(Δρ)in alloys.The calculated results agree well with the results of real production.Therefore,the calculation method of terminal rolling tensile and yield strength in the non-quenched-tem-pered steel containing pearlite is given by the alloying electron structure parameters.

Effect of electrode surface roughness on electrical breakdown in high voltage apparatus

This paper considers the statistical theory of electrical breakdowns in high voltage (HV) devices. The extended probability distribution of breakdown is deduced for nonuniform gaps. The breakdown of high voltage apparatus is sensitive to local irregularity of the electric field which may result from the presence of defects such as surface roughness. The surface roughness leads to existence of localized microscopic projection with local electric field strength at the projection top larger than the average field at the electrode surface. The link between parameters determining the probability of electrical breakdown and the parameters determining microscopic geometry of electrode surface is obtained. In this paper a simplified breakdown model is used as a basis for statistical treatment. According to the model the breakdown proceeds if the electric field strength at the projection top exceeds the critical value. The method of dielectric strength calculation for HV devices using a simplified model of breakdown is presented. The paper gives an example of calculation of the breakdown voltage for vacuum switch TVS-43. Results of calculations are compared with available experimental data and Weibull distribution

Primary Response Assessment Method for Concept Design of Monotonous Thin-Walled Structures

A concept design methodology for monotonous, tapered thin-walled structures (wing/fuselage/ship/bridge) is presented including modules for: model generation; loads; primary (longitudinal) and secondary (transverse) strength calculations; structural feasibility (buckling/fatigue/ultimate strength criteria); design optimization modules based on ES/GA/FFE; graphics. A method for primary strength calculation is presented in detail. It provides the dominant response field for design feasibility assessment. Bending and torsion of the structure are modelled with the accuracy required for concept design. A ‘2.5D-FEM’ model is developed by coupling a 1D-FEM model along the ‘monotonity’ axis and a 2D-FEM model(s) transverse to it. The shear flow and stiffness characteristics of the cross-section for bending and pure/restrained torsion are given, based upon the warping field of the cross-section. Examples: aircraft wing and ship hull.

A new method of strength calculation and lifetime prediction of pipe bends operating in the creep range

An easy to use method for an approximate creep life prediction for pipe bends was developed within a recent R & D-project in Germany. The new algorithm is based on a Finite-Element parameter study comprising approximately 200 pipe bends. The creep behaviour of the materials primarily used for main steam and hot reheat piping is described using the Graham–Walles creep law. Since the new algorithm considers the time dependent out-of-roundness and stress redistribution of the pipe bend, it yields a more precise creep life prediction, compared to standard piping codes. It is possible to integrate this new calculation into existing online lifetime-monitoring-systems.