Connections Checks of Pipe-Laying Barge Stinger System under Complex Loading Conditions

2013 ◽  
Vol 365-366 ◽  
pp. 241-244
Author(s):  
Tian Feng Zhao ◽  
Jin Long Qi ◽  
Huan Hong Zhou ◽  
Meng Lan Duan
Keyword(s):  
Mechanism Design ◽  
Structural Response ◽  
Complex Loading ◽  
Beam Element ◽  
Operating Conditions ◽  
Response Analysis ◽  
Knee Brace ◽  
Environmental Loads ◽  
Truss Model ◽  
Survival Case

Fixed stinger system hanging in the stern to implement pipeline S-lay mainly includes an A-frame, a stinger hitch section, a stinger tail section, a knee-brace and a knee-brace hitch. Expect the functional loads the stinger system may suffer environmental loads in construction area and also the inertia loads induced by barge movements. Contrasting to the design of stinger truss, connection mechanism design becomes more complicated for the unknown loads shared during the laying cases or the survival case of the barge. In this paper a set of analytical approach for connection mechanism design are proposed and demonstrated for specific operating conditions. In this approach, structural response analysis were carried out firstly using a beam-element truss model to which pipelay functional loads, environmental loads and inertia loads had been applied and the loads undertook by stinger connections were extracted. Next other connection models constructed by cell grids were enabled to predict the responses of connections under those loads extracted from the analysis results of the first step. The analysis example of this paper confirms that based on this approach more careful strength or fatigue check had been realized for the connections of fixed stinger.

scholarly journals Stereo-DIC Measurements of a Vibrating Bladed Disk: In-Depth Analysis of Full-Field Deformed Shapes

2021 ◽  
Vol 11 (12) ◽  
pp. 5430
Author(s):  
Paolo Neri ◽  
Alessandro Paoli ◽  
Ciro Santus
Keyword(s):  
Single Point ◽  
Excitation Frequency ◽  
Phase Variation ◽  
Operating Conditions ◽  
Image Correlation ◽  
Response Analysis ◽  
Full Field ◽  
Low Speed ◽  
Bladed Disk ◽  
Depth Analysis

Vibration measurements of turbomachinery components are of utmost importance to characterize the dynamic behavior of rotating machines, thus preventing undesired operating conditions. Local techniques such as strain gauges or laser Doppler vibrometers are usually adopted to collect vibration data. However, these approaches provide single-point and generally 1D measurements. The present work proposes an optical technique, which uses two low-speed cameras, a multimedia projector, and three-dimensional digital image correlation (3D-DIC) to provide full-field measurements of a bladed disk undergoing harmonic response analysis (i.e., pure sinusoidal excitation) in the kHz range. The proposed approach exploits a downsampling strategy to overcome the limitations introduced by low-speed cameras. The developed experimental setup was used to measure the response of a bladed disk subjected to an excitation frequency above 6 kHz, providing a deep insight in the deformed shapes, in terms of amplitude and phase distributions, which could not be feasible with single-point sensors. Results demonstrated the system’s effectiveness in measuring amplitudes of few microns, also evidencing blade mistuning effects. A deeper insight into the deformed shape analysis was provided by considering the phase maps on the entire blisk geometry, and phase variation lines were observed on the blades for high excitation frequency.

Analytical investigation of nonlinear heave-coupled response of tension leg platform

2018 ◽  
Vol 233 (3) ◽  
pp. 699-713
Author(s):  
Mohammad Reza Tabeshpour ◽  
Reza Hedayatpour
Keyword(s):  
Degrees Of Freedom ◽  
Structural Response ◽  
Wave Theory ◽  
Equation Of Motion ◽  
Analytical Investigation ◽  
Response Analysis ◽  
Wave Forces ◽  
Tension Leg Platform ◽  
Heave Motion ◽  
Diffraction Effects

Having deep view in structural response of tension leg platform is important issue not only for response analysis but also for engineering design. Coupling between surge and heave motions of tension leg platform is such a problem. Here, tension leg platform motions are considered only in surge and heave degrees of freedom without pitch effect. The coupled term of heave is a nonlinear differential equation. Because the focus of this article is on this term, therefore, Duffing equation of motion in the surge direction is linearized. The wave forces are calculated using Airy’s wave theory and Morison’s equation, ignoring the diffraction effects. Current force also can be very important in dynamic analysis of tension leg platform. Because it affects the term of heave that is coupled with surge. It is shown that the effect of surge motion coupling on heave motion is very important in large displacement of surge motion in many sea states. The main result is that the coupling effects appeared in some frequencies such as heave and surge frequency, twice the frequency of wave, twice the natural surge frequency, and summation and difference of frequency of wave and surge frequency.

scholarly journals Flame response to high-frequency oscillations in a cryogenic oxygen/hydrogen rocket combustor

2019 ◽  
Author(s):  
N. Fdida ◽  
J. Hardi ◽  
H. Kawashima ◽  
B. Knapp ◽  
M. Oschwald ◽  
...  
Keyword(s):  
High Frequency ◽  
Acoustic Resonance ◽  
High Amplitude ◽  
Operating Conditions ◽  
Test Facility ◽  
Response Analysis ◽  
Rocket Engines ◽  
Acoustic Oscillations ◽  
Spatially Resolved ◽  
Flame Response

Experiments presented in this paper were conducted with the BKH rocket combustor at the European Research and Technology Test Facility P8, located at DLR Lampoldshausen. This combustor is dedicated to study the effects of high magnitude instabilities on oxygen/hydrogen flames, created by forcing high-frequency (HF) acoustic resonance of the combustion chamber. This work addresses the need for highly temporally and spatially resolved visualization data, in operating conditions representative of real rocket engines, to better understand the flame response to high amplitude acoustic oscillations. By combining ONERA and DLR materials and techniques, the optical setup of this experiment has been improved to enhance the existing database with more highly resolved OH* imaging to allow detailed response analysis of the flame. OH* imaging is complemented with simultaneous visible imaging and compared to each other here for their ability to capture flame dynamics.

scholarly journals Assessment of Structural Performance and Integrity for Vibration-based Energy Harvester in Frequency Domain

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 357
Author(s):  
Ji-Won Jin ◽  
Ki-Weon Kang
Keyword(s):  
Frequency Domain ◽  
Natural Frequency ◽  
Production Efficiency ◽  
Performance Test ◽  
Energy Harvester ◽  
Structural Integrity ◽  
Structural Response ◽  
Structural Performance ◽  
Railway Vehicle ◽  
Response Analysis

A vibration-based energy harvester (VEH) utilizes vibrations originated from various structures and specifically maximizes the displacement of its moving parts, using the resonance between the frequency of external vibration loads from the structure and the natural frequency of VEH to improve power production efficiency. This study presents the procedure to evaluate the structural performance and structural integrity of VEH utilized in a railway vehicle under frequency domain. First of all, a structural performance test was performed to identify the natural frequency and assess the structural response in frequency domain. Then, the static structural analysis was carried out using FE analysis to investigate the failure critical locations (FCLs) and effect of resonance. Finally, we conducted a frequency response analysis to identify the structural response and investigate the structural integrity in frequency domain. Based on these results, the authors assessed the structural performance and integrity of VEHs in two versions.

scholarly journals A Review of the Flow-Induced Noise Study for Centrifugal Pumps

2020 ◽  
Vol 10 (3) ◽  
pp. 1022 ◽  
Author(s):  
Chang Guo ◽  
Ming Gao ◽  
Suoying He
Keyword(s):  
Optimization Design ◽  
Sound Field ◽  
Operating Conditions ◽  
Response Analysis ◽  
Centrifugal Pumps ◽  
Noise Optimization ◽  
Operating Stability ◽  
Study Results ◽  
Flow Induced Noise ◽  
Negative Impacts

Flow-induced noise is a significant concern for the design and operation of centrifugal pumps. The negative impacts of flow-induced noise on operating stability, human health and the environment have been shown in many cases. This paper presents a comprehensive review of the flow-induced noise study for centrifugal pumps to synthesize the current study status. First, the generation mechanism and propagation route of flow-induced noise are discussed. Then, three kinds of study methodologies, including the theoretical study of hydrodynamic noise, numerical simulation and experimental measurement study, are summarized. Subsequently, the application of the three study methodologies to the analysis of the distribution characteristics of flow-induced noise is analyzed from aspects of the noise source identification and comparison, the frequency response analysis, the directivity characteristics of sound field and the noise changing characteristics under various operating conditions. After that, the analysis of the noise optimization design of centrifugal pumps is summarized. Finally, based on previous study results, this paper puts forward the unsolved problems and implications for future study. In conclusion, the information collected in this review paper could guide further study of the flow-induced noise of centrifugal pumps.

Numerical Simulation on Fatigue Life Assessment of Free Span for Submarine Pipeline

2015 ◽  
Vol 750 ◽  
pp. 153-159
Author(s):  
Jie Dong ◽  
Xue Dong Chen ◽  
Bing Wang ◽  
Wei He Guan ◽  
Tie Cheng Yang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Fatigue Life ◽  
Oil And Gas ◽  
Structural Response ◽  
Simulation Method ◽  
Life Assessment ◽  
Response Analysis ◽  
Submarine Pipeline ◽  
Fatigue Life Assessment ◽  
Harmonic Response Analysis

The upper and lower courses of sea oil and gas exploitationare connected by submarine pipeline which is called life line project. Free span often occurs because of the unevenness and scour of seabed, and fatigue is one of the main failure modes.In this paper, with the finite element numerical simulation method, based on the harmonic response analysis, the research on the structural response of free span under the vibration induced by vortex was investigated, and the effect of the factors such as flow velocity, length of free span. According to the analysis results,the fatigue life of free span was evaluated.

New Seismic Design Specifications of Highway Bridges in Japan

1994 ◽  
Vol 10 (2) ◽  
pp. 333-356 ◽  
Author(s):  
Kazuhiko Kawashima ◽  
Kinji Hasegawa
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Response ◽  
Seismic Design ◽  
Structural Response ◽  
Highway Bridges ◽  
Lateral Force ◽  
Inertia Force ◽  
Response Analysis ◽  
Design Specifications ◽  
Recent Earthquakes

This paper presents the new seismic design specifications for highway bridges issued by the Ministry of Construction in February 1990. Revisions of the previous specifications were based on the damage characteristics of highway bridges that were developed after the recent earthquakes. The primary revised items include the seismic lateral force, evaluation of inertia force for design of substructures considering structural response, checking the bearing capacity of reinforced concrete piers for lateral load, and dynamic response analysis. Emphasis is placed on the background of the revisions introduced in the new seismic design specifications.

Dynamic Load Response Analysis on Yaw Bearing of Wind Turbine to Turbulent Wind

2019 ◽  
Author(s):  
Jianwen Xu
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Gumbel Distribution ◽  
Operating Conditions ◽  
Likelihood Method ◽  
Coupled Analysis ◽  
Response Analysis ◽  
Turbulent Wind ◽  
Load Response ◽  
Yaw Bearing

Abstract Wind turbines are subjected to dynamic loads during their service life. The yaw bearing is an important part which also bears these loads. In this study, a series of 5-megawatt (MW) wind turbines are analyzed for their dynamic response under normal operating conditions while exposed to turbulent wind. These models are Onshore, Monopile, ITI Barge, Spar, Tension-Leg Platform (TLP), Semi-Submerisible. TurbSim is used to prescribe turbulent-wind inflow and a time domain FAST code is applied in order to conduct the Aero-Hydro-Servo-Elastic coupled analysis on the yaw loads of the wind turbines. Three different average wind velocities are examined to compare the load response of the wind turbine to turbulent wind on the yaw bearing. A Gumbel distribution coupled maximum likelihood method is used to predict ultimate loads. And the rain flow counting algorithm, the linear cumulative damage law and S-N curve theory are used to predict the damage equivalent load. The results should aid the fatigue design of yaw bearing and the yaw control system according to different wind turbine design.

Effects of Empirical Orthogonal Functions in Simplification of Structural Response of a Deep-Water Offshore System Under Current Profile Loading

2020 ◽  
Author(s):  
Michael Binsar Lubis ◽  
Mehrdad Kimiaei ◽  
Hongwei An ◽  
Reza Azarhoush
Keyword(s):  
Deep Water ◽  
Structural Response ◽  
Time History ◽  
Empirical Orthogonal Functions ◽  
Response Analysis ◽  
Good Representation ◽  
Current Profile ◽  
Orthogonal Functions ◽  
Recent Developments ◽  
Guidelines And Standards

Abstract Typical recommended current profiles for marine operations can be found in offshore engineering guidelines and standards. However, for some offshore components (e.g. risers, umbilicals, risers) typical simplified current profiles can easily lead to unrealistic and conservative results. Due to recent developments in current measuring technology, current speed for deep water location can be easily acquired. However, the current speeds are usually recorded for long periods and in many measurement points along the water column. Hence, finding the extreme current profile based on the recorded time-history data is not an easy task since it needs excessive computational efforts. To determine the overall response of an offshore system, various methods have been developed to minimize the required computational efforts in working with big number of irregular current profiles. Mode-based analysis using empirical orthogonal functions is one of these methods. Total number of the utilized modes plays an important role in the numerical complexity of the problem as well as the accuracy of the results. In this study, for a given deep water location, the effects of the reduced number of modes are investigated through response analysis of a simple vertical fixed slender structure under thousands of current profiles. It is found that the reduced-mode profile can produce a good representation of the measured current profile, however it tends to underestimate the structural response.

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