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The paper describes the simulation of impact loads applied on plate panels with welding-induced residual stresses and deformation (WSD). Numerical simulations using FEM are carried out to study the influence of welding-induced residual stresses and deformation on the impact strength of plate panels. Welding is simulated using a three dimensional thermal mechanical coupled finite element method. The welding stress and deformation are taken as the initial imperfections in the impact strength analysis and their influence on the behavior of plate panels subjected to impact loadings. The impact loadings from the three directions, the lateral direction and two in-plane directions of the plate panels are studied. Results show a certain reduction in the impact strength due to the existence of welding stress and deformation in the plate panels. It is found that the reduction of impact force is strongly influenced by the welding deformation and the impact directions in the plate panels. This reduction is more significant when the impact force is in the lateral direction.

The structural design of ships concerning grounding and collision requires an accurate prediction of the damage of plate panels under impact loading. Several experimental works on laterally loaded panels have been conducted in order to derive analytical expressions [

This research work is aimed to investigate the influence of welding-induced residual stresses and deformation (WSD) on the impact strength of plate panels. Since experimental investigations on partial and/or full scale welded plate panels are difficult, FEM is often used to simulate the impact behaviors of plate panels subjected to a striking object such as a ball or a rigid frame. The previous study [

The computation methods and procedures used in analyzing impact strength of plate panels with welding-induced residual stresses and deformation are summarized in

Three dimensional welding heat conduction analysis on a butt welded plate panel is carried out using a research version of the in-house FEM solver JWRIAN developed by authors [

A coupled thermal-elastic plastic analysis is performed to estimate the welding residual stresses and deformation using the in-house software JWRIAN.

Implicit dynamic analyses using ABAQUS Ver. 6-13 [

Material properties of plate panels and its characteristics are as shown in

Mechanical properties of the material | ||||
---|---|---|---|---|

Young’s | Poisson | Yield | Tensile | Failure |

Modulus | Ratio | Stress | Stress | Strain |

210 Gpa | 0.3 | 320 Mpa | 480 Mpa | 35% |

A square plate panel 600 × 600 × 6 mm is modeled using eight node hexa elements as shown in

The effect of initial imperfections, welding residual stresses and deformation (WSD), are taken into account in the plate panel when subjected to impact loadings. A volumetric heat source is applied through the welding line. The problem is treated as a de-coupled thermal-mechanical analysis. However, temperature dependent mechanical properties are used. First, a thermal analysis was performed to predict the temperature history of the plate panel. Subsequently, thermal loads induced by transient welding temperature fields were applied to the plate panel and residual stresses were predicted using a nonlinear thermal elastic plastic FEM [

By considering the welding residual stresses and deformation (WSD) shown in

perfections, a lateral impact loading in Y-direction is applied as shown in

In this section, in-plane impact loading in Z-direction as shown in

two plates have almost the same initial stiffness. The influence of the initial welding imperfections on impact deformation near the center of the plate can be clearly observed. The deflection mode of the plate with WSD follows the mode of initial deflection, while the flat plate has a strong effect on a post buckling mode.

In this section, in-plane impact loading in X-direction as shown in

The paper refers to the simulation impact of plate panels with welding stress and deformation (WSD). Two different directions of impact loadings on plate panels such as lateral impact and in-plane impacts are investigated. The following related aspects are considered to be essential for such a research work:

Whatever the direction of impact loading, the occurrence of welding stress and deformation has a significant role in the reduction of the impact strength of the plate panels. The reduction of impact force is found to be dependent on the mode of initial deflection and direction of impact loading in the plate panels. The reduction is more significant when the impact force is in the lateral direction.

Regarding to lateral impact, the stiffness of the plate panel with WSD is reduced from the beginning of impact loading. After yielding of the plate panel, the impact force is drastically decreased and its value reaches to zero force.

Regarding to in-plane impact in Z-direction, the deflection mode for the plate panel with WSD follows the mode of initial deflection, while the flat plate behaves post buckling mode. For in-plane impact in X-direc- tion, the influence of the initial welding imperfections is less significant on the impact strength and behavior of the plate panels.

As the value of initial deflection is increased in the plate panels, as the reduction in the impact force is increased.

Authors would like to express their acknowledgments to Mr. Hui Huang, JWRI, Osaka University for his support in simulation works.

YehiaAbdel-Nasser,NinshuMa,SherifRashed,HidekazuMurakawa, (2016) Impact Strength Analysis of Plate Panels with Welding-Induced Residual Stress and Deformation. World Journal of Mechanics,06,8-17. doi: 10.4236/wjm.2016.61002