Numerical study on the dynamic response of a truncated ship-hull structure under asymmetrical slamming

2020 ◽  
Vol 72 ◽  
pp. 102767 ◽  
Author(s):  
Hang Xie ◽  
Fang Liu ◽  
Haoyun Tang ◽  
Xinyu Liu
Keyword(s):  
Dynamic Response ◽  
Numerical Study ◽  
Ship Hull ◽  
Hull Structure

Dynamic Response Analysis of Ship Hull Structures

2000 ◽  
Vol 37 (03) ◽  
pp. 117-128
Author(s):  
T. V. S. R. Appa Rao ◽  
Nagesh R. Iyer ◽  
J. Rajasankar ◽  
G. S. Palani
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Dynamic Response ◽  
Finite Element Model ◽  
Element Model ◽  
Ship Hull ◽  
Response Analysis ◽  
Dynamic Response Analysis ◽  
Hull Structure ◽  
The Finite Element Model

Finite-element modeling and use of appropriate analytical techniques play a significant role in producing a reliable and economic design for ship hull structures subjected to dynamic loading. The paper presents investigations carried out for the dynamic response analysis of ship hull structures using the finite-element method. A simple and efficient interactive graphical preprocessing technique based on the "keynode" concept and assembly-line procedure is used to develop the finite-element model of the hull structure. The technique makes use of the body plan of a ship hull to build the finite-element model through an interactive session. Stiffened plate/shell finite elements suitable to model the hull structure are formulated and used to model the structure. The finite elements take into account arbitrary placement of stiffeners in an element without increasing the number of degrees-of-freedom of the element. A three-dimensional finite-element model and a procedure based on the Bubnov-Galerkin residual approach are employed to evaluate the effects of interaction between the ship hull and water. Mode superposition technique is used to conduct the dynamic response analysis. The efficiency of the finite elements and the procedures is demonstrated through dynamic analysis of a submerged cantilever plate and a barge when both are subjected to sinusoidal forces. The dynamic responses exhibit expected behavior of the structure and a comparison with the results available in the literature indicate superior performance of the finite element and methodologies developed. Thus, the finite-element models and the procedures are found to be efficient and hence suitable for the dynamic analysis of similar structures.

Numerical Methods for Hull Structure Strength Analysis and Ships Service Life Evaluation, for a LPG Carrier

2008 ◽  
Author(s):  
Leonard Domnisoru ◽  
Dumitru Dragomir ◽  
Alexandru Ioan
Keyword(s):  
Service Life ◽  
Dynamic Response ◽  
Ship Hull ◽  
Design Stage ◽  
Head Wave ◽  
Strength Analysis ◽  
Response Analysis ◽  
Wave Loads ◽  
Life Evaluation ◽  
Hull Structure

In this paper the authors focus on the ship hull structure strengths and fatigue analyses, in order to estimate the ship service life period at the initial design stage. The topic of the paper is divided in three-interlinked parts. The first part includes the method for the hull strength analysis, based on 3D/1D-FEM models, under equivalent quasi-static head wave loads. The second part presents the method for the ship hull dynamic response analysis, based on non-linear hydroelasticity theory with second order wave spectrum. The last part includes the fatigue analysis method for the initial ship hull structure, based on the long-term prediction ship dynamic response, the cumulative damage ratio and the design S-N material curves. The numerical analyses are carried out for a LPG carrier with independent cargo-tanks type A. Two significant load cases are considered: full and ballast. The numerical results outline the extreme wave loads and the ships initial service life evaluation.

Dynamic Response Analysis of Butt Joint of HTS-A Steel Considering Welding Residual Stresses

2013 ◽  
Vol 423-426 ◽  
pp. 944-950
Author(s):  
Wei Shen ◽  
Ren Jun Yan ◽  
Lin Xu ◽  
Kai Qin ◽  
Xin Yu Zhang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Dynamic Response ◽  
Hot Spot ◽  
Time History ◽  
High Strength ◽  
Simulation Method ◽  
Butt Joint ◽  
Welding Residual Stress ◽  
Response Analysis ◽  
Hull Structure

This paper uses both numerical simulation method and experimental research method to study on welding residual stress of high-strength steel of the cone-cylinder hull. Welding is often accompanied by a larger welding residual stress, which directly affects the safety and service life of the hull structure. In order to obtain the distribution of the welding residual stress, the welding procedure was developed by its parameter language by using FE analysis software in this paper. Then the welding residual stress of hot spot region was measured through X-ray nondestructive testing method, and compared it with simulation results. Finally, considering the residual stress as the initial stress, this paper analyzed dynamic response process of the welding structure under combined actions of the welding residual stress and multiaxial loads, which could more accurately determine the stress of welding structure and the location of fatigue risk point. According to the amplitude of damage parameters and strain time-history curve, we can estimate the fatigue life of structure by selecting the corresponding damage models.

Residual Stress on Ship Hull Structure

1998 ◽  
Vol 14 (04) ◽  
pp. 277-286
Author(s):  
Yasuhisa Okumoto
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Ship Hull ◽  
Ship Structure ◽  
Heat Process ◽  
Steel Material ◽  
Hull Structure ◽  
Hull Strength

It is well known that ship structure experiences residual stresses due to heat process of steelmaking and assembly (cutting, bending, welding, straightening, etc.), and that these stresses affect ship hull strength. However, such stresses are usually not considered in strength calculations, because they are quantitatively ambiguous. This paper reviews the residual stresses in ship hull structure in accordance with each production step, including steel material, with reference to past measurements and analyses.

Online Dynamic Response Reconstruction in the Presence of Observation Outliers

2021 ◽  
Author(s):  
Chaodong Zhang ◽  
Jian’an Li ◽  
Youlin Xu
Keyword(s):  
Kalman Filter ◽  
Dynamic Response ◽  
Numerical Study ◽  
Frame Structure ◽  
System Model ◽  
Measurement Information ◽  
Model Errors ◽  
Process Noise ◽  
Robust Kalman Filter ◽  
Response Reconstruction

Previous studies show that Kalman filter (KF)-based dynamic response reconstruction of a structure has distinct advantages in the aspects of combining the system model with limited measurement information and dealing with system model errors and measurement Gaussian noises. However, because the recursive KF aims to achieve a least-squares estimate of state vector by minimizing a quadratic criterion, observation outliers could dramatically deteriorate the estimator’s performance and considerably reduce the response reconstruction accuracy. This study addresses the KF-based online response reconstruction of a structure in the presence of observation outliers. The outlier-robust Kalman filter (OKF), in which the outlier is discerned and reweighted iteratively to achieve the generalized maximum likelihood (ML) estimate, is used instead of KF for online dynamic response reconstruction. The influences of process noise and outlier duration to response reconstruction are investigated in the numerical study of a simple 5-story frame structure. The experimental work on a simply-supported overhanging steel beam is conducted to testify the effectiveness of the proposed method. The results demonstrate that compared with the KF-based response reconstruction, the proposed OKF-based method is capable of dealing with the observation outliers and producing more accurate response construction in presence of observation outliers.

scholarly journals DEVELOPMENT OF STRUCTURAL SOLUTIONS FOR PREVENTION OF WAVE RUN-UP OF THE BOW

2017 ◽  
pp. 7-14
Author(s):  
Pavel Evgenievich Burakovskiy
Keyword(s):  
Hydrodynamic Force ◽  
Stability Loss ◽  
Critical Value ◽  
Ship Hull ◽  
Hydrodynamic Impact ◽  
Hull Structure ◽  
Run Up ◽  
Hull Damage ◽  
Structural Solutions ◽  
Navigation Safety

One of the most dangerous situations for seagoing ships is wave run-up in a head sea. In such a case, significant hydrodynamic forces appear resulting in stability loss or ship hull damage. The paper presents structural solutions that contribute towards navigation safety by means of decreasing probability of wave run-up of the ship bow in a head sea. A design has been developed of a ship stabilizer in the form of hinge-mounted stabilizing wings which deflect from the hull when the bow submerges in water and then cling to it when it emerges. The paper presents a new design of the bulwark with rotating sections able to rotate in the direction from the deck to the board. These designs can reduce dipping in a wave and reduce hydrodynamic impact on the bow. Apart from this, a hull structure has been proposed with a detachable bow to prevent capsizing of a ship. If the hydrodynamic force reaches a critical value, destruction of a permanent joint will happen in the proposed design, resulting in the situation when leak-proof aft and bow parts detach and remain afloat, which will allow the crew to evacuate. The proposed designs will increase navigation safety in storm conditions.

scholarly journals Experimental and Numerical Study on Modal Dynamic Response of Water-Surrounded Slender Bridge Pier with Pile Foundation

2017 ◽  
Vol 2017 ◽  
pp. 1-20 ◽  
Author(s):  
Yulin Deng ◽  
Qingkang Guo ◽  
Lueqin Xu
Keyword(s):  
Dynamic Response ◽  
Water Level ◽  
Pile Foundation ◽  
Numerical Study ◽  
Fluid Structure Interaction ◽  
Bridge Pier ◽  
Experimental Program ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Tip Mass

This paper presents an experimental program performed to study the effect of fluid-structure interaction on the modal dynamic response of water-surrounded slender bridge pier with pile foundation. A reduced scale slender bridge pier specimen is built and tested through forced vibration method. The vibration periods of the first four lateral modes, including the first two modes along x-axis and the first two modes along y-axis, are measured based on the specimen submerged by 16 levels of water and designated with 4 levels of tip mass. Three-dimensional (3D) finite-element models are established for the tested water-pier system and analyzed under various combined cases of water level and tip mass. Percentage increases of vibration periods with respect to dry vibration periods (i.e., vibration periods of the specimen without water) are determined as a function of water level and tip mass to evaluate the effect of fluid-structure interaction. The numerical results are successfully validated against the recorded test data. Based on the validated models, the modal hydrodynamic pressures are calculated to characterize the 3D distribution of hydrodynamic loads on the pier systems. The research provides a better illumination into the effect of fluid-structure interaction on the modal dynamic response of deepwater bridges.

Sign in / Sign up

Export Citation Format

Share Document