Numerical investigation of stress concentration in a large-diameter threaded connection

2007 ◽  
Vol 43 (5-6) ◽  
pp. 243-248
Author(s):  
T. A. Komarova ◽  
Yu. S. Kuz’min ◽  
V. G. Fedosov
Keyword(s):  
Stress Concentration ◽  
Numerical Investigation ◽  
Large Diameter ◽  
Threaded Connection

Numerical investigation of the monotonic drained lateral behaviour of large diameter rigid piles in medium dense uniform sand

Géotechnique ◽  
2021 ◽  
pp. 1-39
Author(s):  
Huan Wang ◽  
M. Fraser Bransby ◽  
Barry M. Lehane ◽  
Lizhong Wang ◽  
Yi Hong
Keyword(s):  
Numerical Investigation ◽  
Load Transfer ◽  
Large Diameter ◽  
Offshore Wind ◽  
Soil Pressure ◽  
Lateral Capacity ◽  
Pile Diameter ◽  
Centrifuge Tests ◽  
Lateral Response ◽  
Loading Eccentricity

This paper presents a numerical investigation of the monotonic lateral response of large diameter monopiles in drained sand with configurations typical of those employed to support offshore wind turbines. Results from new centrifuge tests using instrumented monopiles in uniform dry sand deposits are first presented and used to illustrate the suitability of an advanced hypoplastic constitutive model to represent the sand in finite element analyses of the experiments. These analyses are then extended to examine the influence of pile diameter and loading eccentricity on the lateral response of rigid monopiles. The results show no dependency of suitably normalized lateral load transfer curves on the pile diameter and loading eccentricity. It is also shown that, in a given uniform sand, the profile with depth of net soil pressure at ultimate lateral capacity is independent of the pile diameter because of the insensitivity of the depth to the rotation centre for a rigid pile. A normalization method is subsequently proposed which unifies the load-deflection responses of different diameter rigid piles at a given load eccentricity.

scholarly journals Thread Couplings Stress Analysis by Radial Basis Functions Mesh Morphing

2021 ◽  
pp. 114-120
Author(s):  
Michele Calì ◽  
Salvatore Massimo Oliveri ◽  
Marco Evangelos Biancolini
Keyword(s):  
Stress Concentration ◽  
Radial Basis Functions ◽  
Basis Functions ◽  
Mesh Morphing ◽  
Threaded Connection ◽  
Design Variables ◽  
Radial Basis ◽  
Minimum Stress ◽  
Numerical Finite Element ◽  
Thread Root

AbstractTraditional analytical methods are approximate and need to be validated when it comes to predict the tensional behavior of thread coupling. Numerical finite element simulations help engineers come up with the optimum design, although the latter depends on the constraints and load conditions of the thread couplings which are often variable during the system functioning. The present work illustrates a new method based on Radial Basis Functions Mesh Morphing formulation to optimize the stress concentration in thread couplings which is subject to variable loads and constraints. In particular, thread root and fillet under-head drawings for metric ISO thread, which are the most commonly used thread connection, are optimized with Radial Basis Functions Mesh Morphing. In metric ISO threaded connection, the root shape and the fillet under the head are circular, and from shape optimization for minimum stress concentration it is well known that the circular shape becomes seldom optimal. The study is carried out to enhance the stress concentration factor with a simple geometric parameterization using two design variables. Radial Basis Functions Mesh Morphing formulation, performed with a simple geometric parameterization, has allowed to obtain a stress reduction of up to 12%; some similarities are found in the optimized designs leading to the proposal of a new standard. The reductions in the stress are achieved by rather simple changes made to the cutting tool.

Use of Tubular Joint Stress Concentration Factor Parametric Formulae in the Analysis of Large Diameter Pipework Connections

2000 ◽  
Author(s):  
R. M. Andrews ◽  
S. Wheat ◽  
M. Brown ◽  
C. Fowler
Keyword(s):  
Stress Concentration ◽  
Stress Analysis ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Large Diameter ◽  
Joint Stress ◽  
Tubular Joints ◽  
Tubular Joint ◽  
Potential Use ◽  
Pipe Joint

Parametric formulae derived for offshore structural tubular joints have been assessed for potential use for estimating stress intensification factors for pipe stress analysis. The background to these equations is given and comparisons made for a range of typical geometries. Despite the absence of a “plug” of material in a pipe joint, the tubular joint equations appear suitable for the estimation of stress intensification factors for fabricated tees subjected to moment loading of the branch. It is considered that this approach should be investigated further by code developers.

Numerical Investigation Based on Orthogonal Design of Structural Parameters on Large-Diameter DTH Hammer Bit

2013 ◽  
Vol 774-776 ◽  
pp. 1442-1445
Author(s):  
Zhi Qiang Zhao ◽  
Li Jia Li ◽  
Kun Bo ◽  
Xu Sheng He ◽  
Jun Feng Chai
Keyword(s):  
Numerical Investigation ◽  
Design Method ◽  
Orthogonal Design ◽  
Structural Parameters ◽  
Large Diameter ◽  
Technical Problem ◽  
Theory Analysis ◽  
Air Volume ◽  
Orthogonal Design Method ◽  
Reverse Circulation

To achieve cutting transport with air reverse circulation in dry and shallow large-diameter holes of rock-socketed pile, and to solve the technical problem with airlift and pump reverse circulation, a large-diameter reverse circulation bit innovatively designed based on ejecting. Meanwhile, the orthogonal design method applied to explore the application feasibility of ejector theory in use of in air reverse circulation drilling. Through theory analysis, three key geometry parameters of air reverse circulation bit have proved to have direct affect on the function of cutting transport, including the diameter of nozzles (Dn), the number of nozzles (N), the angle of inclination (θs). The results have shown that reverse circulation effect of large-diameter bit designed based on ejecting is valid and stable. Further while the air volume of GQF-16 hammer bit goes to 90m3/min, a configuration of parameters with Dn=20mm, N=3, θs=35°are the most ideal parameter combinations.

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