Numerical Investigation of the Damage Mechanism of Offshore Pipeline Impacted by the Lump-Shaped Falling Object

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Han Zhang ◽  
Jie Zhang ◽  
Ruinan Lin ◽  
Yangjie Li
Keyword(s):  
Impact Energy ◽  
Impact Damage ◽  
Three Dimensional ◽  
Damage Mechanism ◽  
Thickness Ratio ◽  
Mechanism Analysis ◽  
Stress Concentrations ◽  
Offshore Pipeline ◽  
Global Deformation ◽  
The Impact

Abstract Damage mechanism analysis of the exposed offshore pipeline impacted by lump-shaped falling objects plays a significant role in offshore pipeline design, inspection, maintenance, and protection. A series of three-dimensional (3D) coupling models are established and simulated to investigate mechanical behaviors and responses of exposed offshore pipelines impacted by lump-shaped falling objects. The effects of both offshore pipeline parameters and lump-shaped falling object parameters were discussed under the joint action of internal pressure and external seawater pressure. The results demonstrate that seabed soil could absorb partial impact energy and act as a cushion. Indentation on the pipeline top and stress concentrations on the pipeline bottom starts to appear when the impact velocity is larger than 10 m/s and 14 m/s, respectively. The critical impact energy before pipeline failure is around 9733.339 J. A variation in contact area has a noticeable influence on the dent depth, but a slight influence on the global deformation. An increase in pressure difference mitigates the impact damage. The depression rate increases with the rise of the radius-thickness ratio, and the most severe plastic deformation occurs when the radius-thickness ratio is 40. Besides, the eccentric distance is an essential factor influencing the damage mechanism of the offshore pipeline.

Experimental Research on CFRP Laminates with Different Impact Energy Levels

2014 ◽  
Vol 1030-1032 ◽  
pp. 1060-1063
Author(s):  
A Ying Zhang ◽  
Dong Xing Zhang
Keyword(s):  
Crack Length ◽  
Impact Energy ◽  
Impact Damage ◽  
Energy Levels ◽  
Three Dimensional ◽  
Fatigue Loading ◽  
Crater Depth ◽  
Cfrp Laminates ◽  
65 J ◽  
The Impact

The effects of thickness and impact energy on the impact damage of CFRP laminates were studied in this paper. Impact tests for the CFRP laminates with the size of 600 mm×700 mm with five different thicknesses were subjected to impact fatigue loading at different energy levels from 5 J to 65 J. The crater depth and matrix length were investigated according to different energy levels and different thicknesses. The impact damage was evaluated by visual inspection, three-dimensional microscope. The experimental results reveal that the crater depth and the crack length increase with the increasing impact energy. For the same impact energy, the crater depth and the crack length decreased with the increasing thickness of specimens.

Low-Energy Impact Damage Mechanism Analysis of FRC Laminates

2013 ◽  
Vol 650 ◽  
pp. 298-303
Author(s):  
Ying Xu ◽  
Wei Dong Wen ◽  
Yu Huo
Keyword(s):  
Impact Damage ◽  
Damage Mechanism ◽  
Low Energy ◽  
Matrix Cracking ◽  
Front Face ◽  
Fiber Direction ◽  
Mechanism Analysis ◽  
Energy Impact ◽  
The Matrix ◽  
The Impact

Aimed at the lack of research about damage mechanism, a 3-D progressive impact damage analysis method was applied to analyze the low-energy impact damage process of T300/BMP-316 laminates with three different ply stacking sequences. The influences of ply parameters on the impact damage of laminates were researched. The impact damage mechanism was analyzed combined with the figure of impact stress in laminates. It is showed that the matrix cracking is caused by the inconsistent distortion of the matrix and fiber when the tensile stress that perpendicular to the fiber direction reaches a given value, and the delamination near to the impacted back face and front face are caused individually by the matrix cracking and the inconsistent bend stiffness between two laminas.

Threshold of Impact Energy on the Medium Leakage of CFRP Laminates

2013 ◽  
Vol 395-396 ◽  
pp. 68-71
Author(s):  
A Ying Zhang ◽  
Zhi Jun Zhang ◽  
Zhen Jia ◽  
Ye Zhang ◽  
Dong Xing Zhang
Keyword(s):  
Impact Energy ◽  
Impact Damage ◽  
Energy Levels ◽  
Three Dimensional ◽  
Crater Depth ◽  
Damage Area ◽  
Cfrp Laminates ◽  
Impact Area ◽  
65 J ◽  
The Impact

The effects of the thickness and the impact energy on the medium leakage of CFRP laminates were discussed in this paper. Impact tests for CFRP laminates with the size of 600 mm×700 mm with three different thicknesses were subjected to impact energy levels from 5 J to 65 J. The medium leakage and the damaged area were investigated according to different energy levels and thicknesses. The damage area was evaluated by visual inspection and three-dimensional microscope. The experimental results reveal that the impact damage of CFRP laminates tends to be more severe as the impact energy increases, and the impact area and the crater depth increases with the increasing impact energy. For the same impact energy, the impact area and the crater depth decrease with the increasing thickness.

Experimental Research on Medium Leakage of CFRP Laminates after Impact

2014 ◽  
Vol 633-634 ◽  
pp. 383-386
Author(s):  
A Ying Zhang ◽  
Dong Xing Zhang
Keyword(s):  
Impact Energy ◽  
Composite Laminates ◽  
Impact Damage ◽  
Energy Levels ◽  
Three Dimensional ◽  
Crater Depth ◽  
Damage Area ◽  
Cfrp Laminates ◽  
Impact Area ◽  
The Impact

The effects of thickness and impact energy on the medium leakage of composite laminates were discussed in this paper. Impact tests for the composite laminates with the size of 600 mm×700 mm with three different thicknesses were subjected to impact energy levels from 5 J to 40 J. The medium leakage and the damaged area were investigated according to different energy levels and stacking sequences. The damage area was evaluated by visual inspection and three-dimensional microscope. The experimental results reveal that the impact damage of CFRP laminates with three different thicknesses tends to be more severe as impact energy increases. The impact area and the crater depth increases with increasing impact energy. The impact area and the crater depth decreases with increasing thickness for the same impact energy.

Experimental Research on the Effects of Dimension on the Impact Damage of CFRP Laminates

2013 ◽  
Vol 395-396 ◽  
pp. 64-67
Author(s):  
A Ying Zhang ◽  
Zhi Jun Zhang ◽  
Zhen Jia ◽  
Ye Zhang ◽  
Dong Xing Zhang
Keyword(s):  
Impact Energy ◽  
Composite Laminates ◽  
Impact Damage ◽  
Energy Levels ◽  
Three Dimensional ◽  
Crater Depth ◽  
Negative Effects ◽  
Cfrp Laminates ◽  
Length Increase ◽  
The Impact

The effects of thickness on the impact damage of composite laminates were discussed in this paper. Impact tests for the composite laminates with the size of 600 mm×700 mm with three different thicknesses were subjected to impact energy levels from 5 J to 40 J. The crater depth and matrix length were investigated according to different energy levels and different thicknesses. The impact damage was evaluated by visual inspection, three-dimensional microscope. The experimental results reveal that the crater depth and the crack length increase with the increasing impact energy. The thickness had the negative effects on the impact damage of the specimens at the same impact energy.

Failure Mechanism Analysis of Electromagnetic Relay under Mechanical Impact

2013 ◽  
Vol 473 ◽  
pp. 39-45 ◽  
Author(s):  
Guo Wei Zhao ◽  
Yong Chen ◽  
De Yong Li ◽  
Bin Tang
Keyword(s):  
Failure Mechanism ◽  
Magnetic Circuit ◽  
Impact Damage ◽  
Engineering Application ◽  
Air Gap ◽  
Mechanism Analysis ◽  
Mechanical Impact ◽  
Electromagnetic Relay ◽  
Electromagnetic Relays ◽  
The Impact

The aim was to analyze failure mechanism of electromagnetic relay caused by mechanical impact. The principle of electromagnetic relays was studied and the effect of mechanical impact on electromagnetic relays was analyzed in this paper. Based on the established magnetic circuit model, the relationship of the magnetic field strength, the electromagnetic attraction and the impact damage degree was studied. Then, the damage intensity of mechanical impact on magnetic circuit was decided. Afterwards, the structure of electromagnetic relays was improved, and the mechanical impact simulation was studied by ANSYS. The results show that the uncontrollability of electromagnetic relay is mainly caused by air gap, which is aroused by mechanical impact; in addition, the size of air gap is inversely proportional to electromagnetic attraction force. Moreover, the improved structure of relays can increase impact resistance and broaden the scope of engineering application of electromagnetic relay.

scholarly journals Crushing Susceptibility of Vetch Seeds Under Impact Loading

2017 ◽  
Vol 50 (4) ◽  
pp. 5-16
Author(s):  
F. Shahbazi
Keyword(s):  
Moisture Content ◽  
Impact Energy ◽  
Impact Loading ◽  
Impact Damage ◽  
Mechanical Damage ◽  
Seed Moisture Content ◽  
Mean Values ◽  
Seed Moisture ◽  
Mathematical Relationships ◽  
The Impact

AbstractMechanical damage of seeds due to harvest, handling and other process is an important factor that affects the quality and quaintly of seeds. The objective of this research was to determine the effects of moisture content and the impact energy on the breakage susceptibility of vetch seeds. The experiments were conducted at moisture contents of 7.57 to 25% (wet basis) and at the impact energies of 0.1, 0.2 and 0.3 J, using an impact damage assessment device. The results showed that impact energy, moisture content, and the interaction effects of these two variables significantly influenced the percentage breakage in vetch seeds (p<0.01). Increasing the impact energy from 0.1 to 0.3 J caused a significant increase in the mean values of seeds breakage from 41.69 to 78.67%. It was found that the relation between vetch seeds moisture content and seeds breakage was non-linear, and the extent of damaged seeds decreased significantlyas a polynomial (from 92.47 to 33.56%) with increasing moisture (from 7.57 to 17.5%) and reached a minimum at moisture level of about 17.5%. Further increase in seed moisture, however, caused an increase in the amount of seeds breakage. Mathematical relationships composed of seed moisture content and impact energy, were developed for accurately description the percentage breakage of vetch seeds under impact loading. It was found that the models have provided satisfactory results over the whole set of values for the dependent variable.

scholarly journals Static Residual Tensile Strength Response of GFRP Composite Laminates Subjected to Low-Velocity Impact

2020 ◽  
Vol 10 (16) ◽  
pp. 5480
Author(s):  
Jong-Il Kim ◽  
Yong-Hak Huh ◽  
Yong-Hwan Kim
Keyword(s):  
Tensile Strength ◽  
Composite Laminates ◽  
Impact Damage ◽  
Image Correlation ◽  
Matrix Cracking ◽  
Low Velocity Impact ◽  
Stress Concentrations ◽  
Low Velocity ◽  
Full Field ◽  
The Impact

The dependency of the static residual tensile strength for the Glass Fiber-Reinforced Plastic (GFRP) laminates after impact on the impact energy level and indent shape is investigated. In this study, two different laminates, unidirectional, [0°2]s) and TRI (tri-axial, (±45°/0°)2]s), were prepared using the vacuum infusion method, and an impact indent on the respective laminates was created at different energy levels with pyramidal and hemispherical impactors. Impact damage patterns, such as matrix cracking, delamination, debonding and fiber breakage, could be observed on the GFRP laminates by a scanning electron microscope (SEM), and it is found that those were dependent on the impactor head shape and laminate structure. Residual in-plane tensile strength of the impacted laminates was measured and the reduction of the strength is found to be dependent upon the impact damage patterns. Furthermore, in this study, stress concentrations in the vicinity of the indents were determined from full-field stress distribution obtained by three-dimensional Digital Image Correlation (3D DIC) measurement. It was found that the stress concentration was associated with the reduction of the residual strength for the GFRP laminates.

Simulation Study on Impact Damage of Aircraft Panel Structure under Stress

2006 ◽  
Vol 324-325 ◽  
pp. 391-394
Author(s):  
Man Yi Hou ◽  
Shu Lin Li ◽  
Yang Yi Jiang ◽  
Shou An Li
Keyword(s):  
High Velocity ◽  
Impact Damage ◽  
Damage Mechanism ◽  
Impact Response ◽  
Finite Element Models ◽  
Compression Stress ◽  
High Velocity Impact ◽  
Simulation Results ◽  
Stress States ◽  
The Impact

Based on ANSYS/LS-DYNA code, the finite-element models were created to simulate the response of the aircraft panel structure impacted by high velocity projectile. The models proved to be effective through the comparison between the results of simulation and relative experiments. Then the impact process was simulated respectively considering the states of various types of stress in the panel. Through analyzing the simulation results, the influence of various stress states in the panel on impact response and damage mechanism was summed up. The conclusions indicated that the stress and particularly compression stress in aircraft panel structure can facilitate much more deformation and damage when the panel suffers high velocity impact.

scholarly journals Low Velocity Impact Assessment of a Carbon Fiber Bicycle Wheel

2021 ◽  
Author(s):  
Karmanya Ratra
Keyword(s):  
Carbon Fiber ◽  
Energy Absorption ◽  
Impact Energy ◽  
Damage Evolution ◽  
Impact Damage ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Test Protocol ◽  
Velocity Impact ◽  
The Impact

Carbon fiber bicycle wheels were tested under low velocity impact to monitor the damage evolution of the impact event. A wheel model designed by KQS Inc. (industrial partner) with eight different configurations, including spoke tension, number of spokes, and location of impact on the rim were investigated. IR thermography combined with PCA was used to monitor the damage during impact. Results showed that wheels in line with spokes had 16% higher impact energy absorption compared to those impacted in between spokes on average (58.9 J vs 70.2 J). The 20 spoked wheels had a slightly higher (6%) impact energy absorption than the 24 spoked wheels. The added stiffness due to the extra spokes reduced the impact energy absorption of rim. Wheels with higher spoke tension also had slightly improved impact energy absorption (4%). The test protocol established in this study provides a good understanding of the wheel’s impact damage evolution.

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