Analysis of the Tightening Process of Bolted Joint With a Tensioner Using Spring Elements

1994 ◽  
Vol 116 (4) ◽  
pp. 443-448 ◽  
Author(s):  
T. Fukuoka

Hydraulic bolt tensioners are frequently used to tighten critical structural members with accurately controlled clamping force. The ratio of desired clamping force to initial tension is the most important factor to be predicted in advance for given joint configurations, which is termed “effective tensile coefficient” here. In this paper, an elementary and extensive approach to estimate the coefficient is proposed using spring elements, and a simple and practical equation is presented to evaluate the magnitude of “effective tensile coefficient” in terms of five spring rates of each part consisting of the joint. The relationship between “effective tensile coefficient” and grip length is investigated, including the influences of Young’s modulus of fastened plate. The validity of the elementary method proposed here is ascertained by comparing the results to those by experiment and FEM.

2000 ◽  
Author(s):  
Toshimichi Fukuoka

Abstract Hydraulic tensioners are widely used in tightening important structural members such as large-sized diesel engines and pressure vessels. The ratio of desired clamping force to initial tension, which is termed effective tensile coefficient, is the most important factor to be predicted in the actual operation for given joint configurations. In this paper, an elementary approach to estimate this coefficient, taking the effects of interface stiffness into account, is proposed using spring elements. The influences of interface stiffness at four contact surfaces on the coefficient are discussed, and it is shown that interface stiffness of pressure flank of threads and bearing surface of nut has dominant effects on the coefficient.


Holzforschung ◽  
2002 ◽  
Vol 56 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Ugai Watanabe ◽  
Minoru Fujita ◽  
Misato Norimoto

Summary The relationship between transverse Young's moduli and cell shapes in coniferous early wood was investigated using cell models constructed by two dimensional power spectrum analysis. The calculated values of tangential Young's modulus qualitatively explained the relationship between experimental values and density as well as the difference in experimental values among species. The calculated values of radial Young's modulus for the species having hexagonal cells agreed well with the experimental values, whereas, for the species having square cells, the calculated values were much larger than the experimental values. This result was ascribed to the fact that the bending moment on the radial cell wall of square cell models was calculated to be small. It is suggested that the asymmetrical shape of real wood cells or the behavior of nodes during ell deformation is an important factor in the mechanism of linear elastic deformation of wood cells.


2010 ◽  
Vol 139-141 ◽  
pp. 594-599
Author(s):  
Yan Qiu Zhang ◽  
Shu Yong Jiang ◽  
Yu Feng Zheng

The spring steel strip 50CrVA which is cold rolled was applied to manufacture the diaphragm of the automotive horn by means of sheet metal forming. The combination of the experiments with back-propagation artificial neural network (BPANN) is used to solve the springback problem of the diaphragm. Experiments have shown that a 4-8-1 BPANN is able to predict the springback of the diaphragm successfully, and the network is able to model the relationship between the springback of the diaphragm and the process parameters rationally. BPANN simulation results and experimental ones have shown that the springback of the diaphragm is particularly influenced by such parameters as blank thickness, Young’s modulus, punch radius and yield ratio. Furthermore, the springback of the diaphragm decreases with the increase of blank thickness and Young’s modulus, but increases with the increase of punch radius and yield ratio.


2011 ◽  
Vol 415-417 ◽  
pp. 455-459
Author(s):  
Xiao Ming Wang ◽  
Fei Wang ◽  
Xue Zeng Zhao ◽  
Da Lei Jing

The modified static bending model of microcantilever with monolayer molecules has been established based on energy method, in which the change in neutral layer position caused by adsorption-induced stress has been considered. On this basis, we have analyzed the relationship between the bending curvature radius of a microcantilever with its thickness, Young’s modulus and molecule-molecule distance of adsorbed molecules when it is adsorbed with monolayer water molecules. Additionally, we have investigated the effect of change in neutral layer position on the static behavior of microcantilever sensors and have found that: 1) the bending curvature radius of microcantilever is affected by its Young’s modulus, thickness and distance of adsorbed molecules respectively; 2)the predicted error of bending curvature radius caused by the change in neutral layer position slightly increases with decreasing Young’s modulus and thickness, whereas the effect of distance between adsorbed molecules on the error is significant.


2019 ◽  
Vol 946 ◽  
pp. 309-314 ◽  
Author(s):  
Anatoly G. Illarionov ◽  
S.V. Grib ◽  
A.V. Huppeev

The relationship between the phase composition and the Young’s modulus in quenched PT-7M, Ti-6Al-7Nb, BT16 titanium alloys has been studied using the structural analysis, thermodynamic calculations in the Thermo-Calc software and micro-indentation. It is found that the nature of the change in the Young’s modulus in the investigated titanium alloys after quenching from the two-phase α+β-region depends on the chemical composition of the alloy, which determines the nature of the observed metastable phases (α', α", ω, β). The correlation between the extreme change in the Young’s modulus from the quenching temperature and the so-called interatomic bonding force (Fb) calculated from the electronic structure parameters of the α, α', β phases was shown for the Ti-6Al-7Nb alloy. The relationship between the limits of the Young’s modulus of the investigated alloys during quenching with the level of their alloying with α-and β-stabilizers is shown.


2019 ◽  
Vol 21 (1) ◽  
Author(s):  
Matthew L. Fitzgerald ◽  
Sara Tsai ◽  
Leon M. Bellan ◽  
Rebecca Sappington ◽  
Yaqiong Xu ◽  
...  

2017 ◽  
Vol 865 ◽  
pp. 366-372
Author(s):  
Jing Sen Liu ◽  
Hai Bo Li ◽  
Guo Kai Zhang ◽  
Jian Deng

In order to improve the accuracy of the rock mechanical parameters, the correlations among physical and mechanical parameters were investigated. A large number of laboratory testing results curried out on 408 rock specimens including metamorphic rocks, sedimentary rocks and igneous rocks. Through the statistical analysis of the laboratory test data, several regression equations among rock material parameters were established. The research suggests that, in addition to Poisson's ratio, the mechanical parameters (unconfined compressive strength (UCS), elastic Young’s modulus, shear modulus) relate well to physical parameters (porosity, P-wave velocity), and the relationships are mainly described by power and exponential correlations which have good squared regression coefficients. The correlation between elastic Young’s modulus and dynamic elastic modulus was established, as well as the relationship between shear modulus and dynamic shear modulus.


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