Ultimate strength of stiffened plates subjected to compressive load and spatially distributed mechanical properties

Author(s):  
K. Woloszyk ◽  
Y. Garbatov
2019 ◽  
Vol 9 (10) ◽  
pp. 2088 ◽  
Author(s):  
Chenfeng Li ◽  
Sen Dong ◽  
Tingce Wang ◽  
Weijun Xu ◽  
Xueqian Zhou

The welded stiffened plate is widely used in naval architecture and offshore engineering as a basic structural member. The aim of this study is to investigate the effect of welding residual stress and steel grade on the ultimate strength of stiffened plates under uniaxial compressive load by non-linear finite element analysis. Nineteen stiffened plates built with three types of stiffeners with various column slenderness ratios provided in the ISSC’2000 VI.2 benchmark calculations are employed in the present study. The commercial finite element code ABAQUS is applied to simulate the collapse behavior of the stiffened plates and verified against the benchmark calculations. Fabrication-related imperfections, such as initial deflections and residual stresses, are accounted for in the simulations. The ultimate strength of stiffened plates built in common shipbuilding steels, namely S235, S315, S355 and S390, are investigated by varying the yield strength of materials in the simulation. Analysis of the numerical results shows that the welding residual stress reduces the ultimate strength of stiffened plates, and increase in yield strength of the material can effectively improve the ultimate strength of common ship stiffened plates; and quantitative analyses of their influences have also been performed.


Author(s):  
Yoshiaki Naruse ◽  
Yasumi Kawamura ◽  
Tetsuo Okada

In this study, ship hull girder ultimate strength considering biaxial compression in bottom stiffened plates is investigated. Firstly, elasto-plastic finite element analysis is carried out for the stiffened plates under biaxial compression by using the commercial FEM software, LS-DYNA. From the observation of collapse behavior of the stiffened plates, it is found that the decrease of the effective width of the stiffened plate under biaxial compression is more rapid compared with the formula in the Common Structure Rules (CSR). This is because the buckling in one half-wave mode occurs when the transverse compressive load becomes larger, while the buckling with multi half-waves mode usually occurs in longitudinal direction when only longitudinal compressive load is applied. Based on the observation, a new formula to estimate ultimate strength of stiffened plates considering biaxial compression is proposed in which three new parameters are introduced which can represent the decrease of the effective width. Next, a method to estimate ultimate strength of hull girder considering the biaxial compression of ship bottom is developed based on the conventional Smith method provided in the CSR, by introducing the above new formula to estimate the ultimate strength of stiffened plates, and by improving the conventional formula of the hard corner element in the Smith method. Finally, the hull girder strength of a container ship under biaxial compression estimated by the proposed method is compared with the result of FEM analysis to show validity of the method.


Author(s):  
Mohammad Reza Khedmati ◽  
Mehran Rastani

The ultimate strength and ductility characteristics of the intermittently welded stiffened plates under the action of in-plane axial compression are investigated in this paper. A series of detailed numerical analyses of longitudinally stiffened steel plates subjected to in-plane compressive load is performed using the ADINA commercial finite element code. Complete equilibrium paths are traced up to collapse for a nonlinear elastic-plastic response of stiffened plates. Analyzed stiffened plates are imperfect and their aspect ratio, plate slenderness, and column slenderness are changed in a systematic manner. Different types of stiffener are chosen for stiffened plate models. Three different stiffener-to-plate welding procedures are considered: continuous, chain intermittent, and staggered intermittent fillet welding.


1977 ◽  
Vol 1977 (141) ◽  
pp. 190-197 ◽  
Author(s):  
Yuzuru Fujita ◽  
Toshiharu Nomoto ◽  
Osamu Niho

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mahmoud Haghighi ◽  
Hossein Golestanian ◽  
Farshid Aghadavoudi

Abstract In this paper, the effects of filler content and the use of hybrid nanofillers on agglomeration and nanocomposite mechanical properties such as elastic moduli, ultimate strength and elongation to failure are investigated experimentally. In addition, thermoset epoxy-based two-phase and hybrid nanocomposites are simulated using multiscale modeling techniques. First, molecular dynamics simulation is carried out at nanoscale considering the interphase. Next, finite element method and micromechanical modeling are used for micro and macro scale modeling of nanocomposites. Nanocomposite samples containing carbon nanotubes, graphene nanoplatelets, and hybrid nanofillers with different filler contents are prepared and are tested. Also, field emission scanning electron microscopy is used to take micrographs from samples’ fracture surfaces. The results indicate that in two-phase nanocomposites, elastic modulus and ultimate strength increase while nanocomposite elongation to failure decreases with reinforcement weight fraction. In addition, nanofiller agglomeration occurred at high nanofiller contents especially higher than 0.75 wt% in the two-phase nanocomposites. Nanofiller agglomeration was observed to be much lower in the hybrid nanocomposite samples. Therefore, using hybrid nanofillers delays/prevents agglomeration and improves mechanical properties of nanocomposite at the same total filler content.


2021 ◽  
Vol 11 (5) ◽  
pp. 2379
Author(s):  
Jeong-Hyeon Kim ◽  
Doo-Hwan Park ◽  
Seul-Kee Kim ◽  
Myung-Sung Kim ◽  
Jae-Myung Lee

The curved plate has been extensively used as a structural member in many industrial fields, especially the shipbuilding industry. The present study investigated the ultimate strength and collapse behavior of the simply supported curved plate under a longitudinal compressive load. To do this, experimental apparatuses for evaluating the buckling collapse test of the curved plates was developed. Then, a series of buckling collapse experiments was carried out by considering the flank angle, slenderness ratio, and aspect ratio of plates. To examine the fundamental buckling and collapse behavior of the curved plate, elastoplastic large deflection analysis was performed using the commercial finite element analysis program. On the basis of both the experimental and FE analysis, the effects of the flank angle, slenderness ratio, and aspect ratio on the characteristics of the buckling and collapse behavior of the curved plates are discussed. Finally, the empirical design formula for predicting the ultimate strength of curved plates was derived. The proposed empirical formula is a good indicator for estimating the behavior of the curved plate.


1999 ◽  
pp. 135-154
Author(s):  
Hiroshi NAKAI ◽  
Toshiyuki KITADA ◽  
Yoshiharu IWAI

2021 ◽  
Author(s):  
Qiang Zhong ◽  
De-yu Wang

Abstract Dynamic capacity is totally different from quasi-static capacity of ship structural components, although most ultimate strength analyses at present by researchers are performed under quasi-static conditions. To investigate the dynamic ultimate strength characteristics, the dynamic ultimate strength analyses of stiffened plates subjected to impact load were studied based on a 3-D nonlinear explicit finite element method (FEM) in this paper. The impact load in the present work is characterized as a half-sine function. A series of nonlinear finite element analyses are carried out using Budiansky-Roth (B-R) criterion. The influence of impact durations, model ranges, boundary conditions, initial imperfections and impact loads on the dynamic ultimate strength of stiffened plates are discussed. In addition, the ultimate strength of stiffened plates under the in-plane impact combined with lateral pressure was also calculated, which shows lateral pressure has a negligible effect on the dynamic ultimate strength of stiffened plates subjected to the impact load with short durations. Other important conclusions can be obtained from this paper, which are useful insights for the development of ultimate strength theory of ship structures and lay a good foundation for the study of dynamic ultimate strength in the future.


Author(s):  
Huilong Ren ◽  
Yifu Liu ◽  
Chenfeng Li ◽  
Xin Zhang ◽  
Zhaonian Wu

There is an increasing interest in the lightweight design of ship and offshore structures, more specifically, choosing aluminum alloys or other lightweight high-performance materials to build structure components and ship equipments. Due to its better mechanical properties and easy assembly nature, extruded aluminum alloy stiffened plates are widely used in hull structures. When the load on the hull reaches a certain level during sailing, partial or overall instability of stiffened plate makes significant contribution in an event of collapse of the hull structure. It is very necessary to investigate the ultimate strength of aluminum alloy stiffened plate to ensure the ultimate bearing capacity of large aluminum alloy hull structure. Most of studies of the ultimate strength of stiffened plates deal with stiffened plates with T–shaped stiffeners. Stiffeners of other shapes have seldom been explored. In this research, the ultimate strength of six different cross–section aluminum alloy stiffened plates and one steel stiffened plate was studied based on the non–linear finite element analysis (FEA). Taking into account stiffness, weight and other issues, the new cross–section aluminum stiffener has finally been concluded for replacing the original steel stiffener in upper deck of a warship.


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