Ultrasonic testing of axial stress of high strength bolts for bridges

2020 ◽  
Vol 64 (1-4) ◽  
pp. 685-692
Author(s):  
Sheng Feng ◽  
Jun Tu ◽  
Shilin Wei ◽  
Yongbin Chi ◽  
Xu Zhang ◽  
...  
Keyword(s):  
Service Life ◽  
Theoretical Analysis ◽  
Ultrasonic Testing ◽  
Axial Stress ◽  
High Strength ◽  
Flight Time ◽  
Measuring Error ◽  
Analysis Method ◽  
Longitudinal And Shear Waves ◽  
Acoustic Elasticity

The axial stress of high strength bolts for bridges affects the service life directly, it is necessary to measure it regularly. Based on the theory of acoustic elasticity and combination of longitudinal and shear waves, a new theoretical analysis method is proposed. The stressed and non-stressed areas of bolt are separated, and the derived formula only use the flight time and difference of acoustoelastic coefficients to get axial stress. Further, the preload experiments with high strength bolts of grade 8.8S and 10.9S is designed, the experimental results show that the proposed method is applicable to the axial stress of the bridge bolts with any specifications, material and different screwing depth used in this paper, the effect of elastic deformation on the flight time is eliminated, and the measuring error is within 5%.

The Study of High Strength Bolt Preload with Hydraulic Tensioner Installation

2011 ◽  
Vol 314-316 ◽  
pp. 988-994 ◽  
Author(s):  
Tie Neng Guo ◽  
Gen Li ◽  
Li Gang Cai ◽  
Zhi Liang Wang
Keyword(s):  
Theoretical Analysis ◽  
Efficient Method ◽  
Theoretical Basis ◽  
High Strength ◽  
Analysis Method ◽  
Heavy Duty ◽  
Initial Tension ◽  
Extension Method ◽  
High Strength Bolt ◽  
Bolt Preload

Preloading the high strength bolt using hydraulic extension method is a fast and efficient method for bolt installation. Hydraulic bolt tension device can guarantee the initial tension of bolt well. However, if the relation of initial tension and the final remaining preload of bolt cannot be determined, the preload on the bolts still cannot be guaranteed. This paper uses theoretical analysis method to research the relation between the eventual preload and the initial tension of high strength bolts on Heavy-duty Gantry beams. Then we proposes a set of calculation method of bolt installation preload and the initial tension and provides theoretical basis for the installation of heavy-duty segmented beam.

AW-TEN

Alloy Digest ◽  
1966 ◽  
Vol 15 (8) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Service Life ◽  
Yield Strength ◽  
High Strength ◽  
Heat Treating ◽  
Bend Strength ◽  
Steel Company ◽  
Superior Corrosion Resistance ◽  
Minimum Yield

Abstract AW-TEN is a high-strength structural steel offering 50,000 psi minimum yield strength, good formability and weldability, and superior corrosion resistance. It is intended primarily for weight reduction and longer service life. It is recommended for automobile and truck bodies, buildings, bridges, railway cars, booms, etc. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive and bend strength as well as fracture toughness and fatigue. It also includes information on forming, heat treating, machining, and joining. Filing Code: SA-199. Producer or source: Alan Wood Steel Company.

Sparse Representation Based Dielectric Loss Angle Measurement

2015 ◽  
Vol 9 (1) ◽  
pp. 566-570
Author(s):  
Zhang Ji ◽  
Jianfeng Zheng
Keyword(s):  
Dielectric Loss ◽  
Power Systems ◽  
Sparse Representation ◽  
Precise Measurement ◽  
Angle Measurement ◽  
Measuring Error ◽  
Loss Angle ◽  
Analysis Method ◽  
Electric Capacity ◽  
Dielectric Loss Angle

Precise measurement of dielectric loss angle is very important for electric capacity equipment in recent power systems. When signal-to-noise is low and fundamental frequency is fluctuating, aiming at the measuring error of dielectric loss angle based on some recent Fourier transform and wavelet transform harmonics analysis method, we propose a novel algorithm based on sparse representation, and improved it to be more flexible for signal sampling. Comparison experiments describe the advantages of our method.

The Theoretical Analysis of Performance Evaluation Connotation of Rural Highway Projects

2012 ◽  
Vol 204-208 ◽  
pp. 1848-1856
Author(s):  
Wu Gong Wang ◽  
Rong Guo Ma ◽  
Kun Feng ◽  
Guo Hua Liang
Keyword(s):  
Public Finance ◽  
Performance Evaluation ◽  
Theoretical Analysis ◽  
Swot Analysis ◽  
Project Performance ◽  
Analysis Method ◽  
Highway Projects ◽  
Rural Highway ◽  
Analysis Of Performance ◽  
Highway Project

On the basis of defining the concept of rural highway project performance, the necessity of the project performance evaluation of rural highway is analyzed. According to the theories of government's public function, fiduciary responsibilities accountability and public finance, the relation between rural highway and public finance are made researches on. Furthermore,with the application of the demand level theory of Maslow, the interrelationship among objects of the rural highway project performance evaluation is made an analysis of, and on top of that, combined with SWOT analysis method, the demand and goal of rural highway project performance evaluation are put forward.

High Strength Conductors and Structural Materials for High Field Magnets

MRS Advances ◽  
2016 ◽  
Vol 1 (17) ◽  
pp. 1233-1239 ◽  
Author(s):  
Ke Han ◽  
Rongmei Niu ◽  
Jun Lu ◽  
Vince Toplosky
Keyword(s):  
Service Life ◽  
High Field ◽  
Lattice Distortion ◽  
Mechanical Load ◽  
Cold Deformation ◽  
High Strength ◽  
Structural Support ◽  
Metal Metal ◽  
Lattice Distortions ◽  
Materials Used

ABSTRACTOne important approach to increasing High magnetic fields (HMF) beyond what is now possible is to improve the properties of various composite materials used as both conductors and structural support. Typical conductors for high field magnets are Cu-based metal-metal composites. To achieve high mechanical strength, these composites are fabricated by cold deformation, which introduces high densities of interfaces along with lattice distortions. During the operation of a magnet, mechanical load, high magnetic field, extreme temperatures and other stressors are imposed on the materials, causing them to be further “processed”. The composite conductors in a magnet, for example, may undergo high temperatures, which reduce lattice distortions or soften the material. At the same time, HMF may increase lattice distortion, leading to a complex change in interface characteristics. Both the mechanical properties of the conductors, like the tensile and yield strength, and the electric conductivity of the composites are closely connected to changes in lattice distortion and interface density. Understanding these changes helps us to assure that materials can operate in optimized conditions during most of magnets’ service life. Maximizing service life is critical, given the high cost of building and operating high field magnets. The goal of this paper is to 1) show our understanding of changes that occur in the properties of selected materials during the fabrication and under HMF and 2) to discuss how those changes relate to the microstructure of these materials and consequently to the service life of high field magnets.

scholarly journals Analysis of Operational Availability of Public City Buses in Selected Periods of Use

2018 ◽  
Vol 19 (12) ◽  
pp. 22-26
Author(s):  
Joanna Rymarz ◽  
Andrzej Niewczas ◽  
Ewa Dębicka
Keyword(s):  
Service Life ◽  
Operating Time ◽  
Analysis Method ◽  
Anova Analysis ◽  
The City

The aim of the article is to compare the operational availability of the city buses. Two popular makes of buses were analysed in the function of time of use, during the six years of operation, in the Municipal Transport Company (MPK) in Lublin. A new division of operating time for the period of full operational usefulness and period of limited operational usefulness of vehicles was presented. It was shown that the average operational availability of the analysed buses differed significantly due to the vehicle's make and also due to the service life. The ANOVA analysis method was used to assess the significance of differences.

Application of Large Size and High Strength Angle in UHV Transmission Line Tower

2014 ◽  
Vol 680 ◽  
pp. 418-421
Author(s):  
Feng Lin Gan ◽  
Xin Wang
Keyword(s):  
Transmission Line ◽  
Axial Stress ◽  
High Strength ◽  
Additional Stress ◽  
Large Size ◽  
Section Area ◽  
Stiffness Variation ◽  
Large Width ◽  
Angle Steel ◽  
Normal Angle

Considering width and thickness of large width angle steel, the section area of large width angle steel is larger than that of normal angle steel. Application of large width angle can increase bearing capacity of the member. Therefore it is feasible that large width angle steel replaces double combined angle steels. Taking the tower for ±800 kV DC transmission line from Jin ping to south Jiangsu Province, under the same design conditions, large width angle steel and double combined angle steels are used respectively in the main members of the tower to modeling finite element analysis.The results indicate that the stiffness variation is more uniform, causing rod end bending bar additional stress is about the axial stress of about 2%~3%.

Experimental Investigation on Forming Limit Curve at Elevated Temperature Through Dome and Biaxial Test

2020 ◽  
Author(s):  
Chetan P. Nikhare ◽  
Evan Teculver ◽  
Faisal Aqlan
Keyword(s):  
Air Pollution ◽  
Fuel Consumption ◽  
Axial Stress ◽  
High Strength ◽  
Tension Test ◽  
Forming Limit ◽  
Biaxial Test ◽  
Limit Curve ◽  
Forming Limit Curve ◽  
Stress States

Abstract The characteristics of metal and materials are very important to design any component so that it should not fail in the life of the service. The properties of the materials are also an important consideration while setting the manufacturing parameters which deforms the raw material to give the design shape without providing any defect or fracture. For centuries the commonly used method to characterize the material is the traditional uniaxial tension test. The standard has been created for this test by American Standard for Testing Materials (ASTM) – E8. This specimen is traditionally been used to test the materials and extract the properties needed for designing and manufacturing. It should be noted that the uniaxial tension test uses one axis to test the material i.e., the material is pulled in one direction to extract the properties. The data acquired from this test found enough for manufacturing operations of simple forming where one axis stretching is dominant. Recently a sudden increase in the usage of automotive vehicles results in sudden increases in fuel consumption which results in an increase in air pollution. To cope up with this challenge federal government is implying the stricter environmental regulation to decrease air pollution. To save from the environmental regulation penalty vehicle industry is researching innovation which would reduce vehicle weight and decrease fuel consumption. Thus, the innovation related to light-weighting is not only an option anymore but became a mandatory necessity to decrease fuel consumption. To achieve this target, the industry has been looking at fabricating components from high strength to ultra-high strength steels or lightweight materials. This need is driven by the requirement of 54 miles per gallon by 2025. In addition, the complexity in design increased where multiple individual parts are eliminated. This integrated complex part needs the complex manufacturing forming operation as well as the process like warm or hot forming for maximum formability. The complex forming process will induce the multi-axial stress states in the part, which is found difficult to predict using conventional tools like tension test material characterization. In many pieces of literature limiting dome height and bulge tests were suggested analyzing these multi-axial stress states. However, these tests limit the possibilities of applying multi-axial loading and resulting stress patterns due to contact surfaces. Thus, a test machine called biaxial test is devised which would provide the capability to test the specimen in multi-axial stress states with varying load. In this paper, two processes, limiting dome test and biaxial test were experimented to plot the forming limit curve. The forming limit curve serves the tool for the design of die for manufacturing operation. For experiments, the cruciform test specimens were used in both limiting dome test and biaxial test and tested at elevated temperatures. The forming limit curve from both tests was plotted and compared. In addition, the strain path, forming, and formability was investigated and the difference between the tests was provided.

Sign in / Sign up

Export Citation Format

Share Document