Coupling Response Analysis of Deep-Water Pipeline Based on Rapid Regulation of Stinger Radius

High strain/stress is easy to occur in the overbend section of S-lay pipelines which are supported by stinger, leading to excessive deformation and buckling failure of the pipelines. In order to ensure the safety of pipelines and evaluate the maximum laying capacity of the pipelay vessel in 1600 meter, this paper uses the curvature radius method to automatically adjust the four angles and roller positions of the articulated stinger fixed on the pipelay vessel, then analyzes the pipeline strain and effective tension in static configuration and finally calculates the timedomain coupling response by establishing a nonlinear contact model of the pipelay vessel, stinger and pipelines. The adjustment speed, which is based on the curvature radius method using Python to call OrcFxAPI, is efficient remarkably. The results show that the stinger radius and roller locations are the major influential factors on the pipeline strain and anchor positions affect the detachment point strain of pipelines on overbend section. The static and dynamic strains of the overbend section are less than 0.25% and 0.305% respectively, which meet the DNV specifications.

WORKING PARAMETERS OF LOAD-BEARING ELEMENT OF HOLE VIBRATION SOURCE

Requirement of oil and gas industry in increasing of rate of hydrocarbon extraction from deposits contributes to development of science-based methods of oil production increasing. Vibrowave impact to productive seam is related to such methods. This impact can be effectively carried out with hole seismic signal sources. In the work results of study of load-bearing element of hole electro-magnetic pulse source are represented. Objective of the work is the study of static and dynamic strains of casing pipe, determination of values of pressure pulses at modified load-bearing element during its work with electro-magnetic striking center. Values of static and dynamic strains of casing pipe under the action of thrust force are experimentally determined. The values are located in flexible zone and make 1mm at the static load and from 0.35 up to 0.6mm at the pulse load. As the results of tests of vibration source prototype, dependence of pulse pressure value at load-bearing element on voltage of striking center supply under the pressure of preliminary pumping 20MPa is obtained. Pulse amplitude raises proportionally voltage in the range from 14.2 MPa up to 19.7 MPa. Experiments with increasing of pumping pressure in the range from 20 MPa up to 27 MPa have shown that ratio of pulse value to pumping pressure linearly reduces when voltage of striking center supply is constant. Obtained results are scientific basic for designing of load-bearing elements destined for work at pulse impact transfer mode.

Limitations of Viscoelastic Constitutive Models for Carbon-Black Reinforced Rubber in Medium Dynamic Strains and Medium Strain Rates

Modelling the viscoelastic behavior of rubber for use in component design remains a challenge. Most of the literature does not consider the typical regimes encountered by anti-vibration devices that are deformed to medium dynamic strains (0.5 to 3.5) at medium strain rates (0.5/s to 10/s). Previous studies have either focused on the behaviour at small strains and small strain rates or in fast loading conditions that result in low cycle fatigue or tearing phenomena. There is a lack of understanding of the dynamic response of natural rubber suspension components when used in real vehicle applications. This paper presents a review of popular viscoelastic nonlinear constitutive models and their ability to model the mechanical behaviour of typical elastomer materials such as Natural Rubber (NR) incorporating different PHR (Parts per Hundred Rubber, XX) of carbon black. The range of strain and strain rate are typical for the materials used in rubber suspensions when operating in severe service operating conditions, such as over rough terrain or over pot-holes. The cyclic strain is applied at different amplitudes and different strain rates in this medium strain range. Despite the availability of many models in the literature, our study reports that none of the existing models can fit the data satisfactorily over a wide range of conditions.