scholarly journals A hybrid embedded cohesive element method for predicting matrix cracking in composites

2016 ◽  
Vol 136 ◽  
pp. 554-565 ◽  
Author(s):  
Mathew W. Joosten ◽  
Matthew Dingle ◽  
Adrian Mouritz ◽  
Akbar A. Khatibi ◽  
Steven Agius ◽  
...  
Keyword(s):  
Matrix Cracking ◽  
Cohesive Element ◽  
Element Method

Parameter Sensitivity in Numerical Modelling of Ice-Structure Interaction With Cohesive Element Method

2016 ◽  
Author(s):  
Dianshi Feng ◽  
Sze Dai Pang ◽  
Jin Zhang
Keyword(s):  
Element Model ◽  
Offshore Structures ◽  
Parameter Sensitivity ◽  
The Arctic ◽  
Cohesive Element ◽  
Structure Interaction ◽  
Marine Structure ◽  
Ice Loads ◽  
The Stability ◽  
Element Method

The increasing marine activities in the Arctic has resulted in a growing demand for reliable structural designs in this region. Ice loads are a major concern to the designer of a marine structure in the arctic, and are often the principal factor that governs the structural design [Palmer and Croasdale, 2013]. With the rapid advancement in computational power, numerical method is becoming a useful tool for design of offshore structures subjected to ice actions. Cohesive element method (CEM), a method which has been widely utilized to simulate fracture in various materials ranging from metals to ceramics and composites as well as bi-material systems, has been recently applied to predict ice-structure interactions. Although it shows promising future for further applications, there are also some challenging issues like high mesh dependency, large variation in cohesive properties etc., yet to be resolved. In this study, a 3D finite element model with the use of CEM was developed in LS-DYNA for simulating ice-structure interaction. The stability of the model was investigated and a parameter sensitivity analysis was carried out for a better understanding of how each material parameter affects the simulation results.

Evaluation of interfacial properties in SiC composites using an improved cohesive element method

2018 ◽  
Vol 29 (2) ◽  
Author(s):  
Hang Zang ◽  
Xing-Qing Cao ◽  
Chao-Hui He ◽  
Zhi-Sheng Huang ◽  
Yong-Hong Li
Keyword(s):  
Interfacial Properties ◽  
Cohesive Element ◽  
Sic Composites ◽  
Element Method

scholarly journals Simulation of Ice-Propeller Collision with Cohesive Element Method

2019 ◽  
Vol 7 (10) ◽  
pp. 349 ◽  
Author(s):  
Zhou ◽  
Wang ◽  
Diao ◽  
Ding ◽  
Yu ◽  
...  
Keyword(s):  
Rotational Speed ◽  
Constitutive Law ◽  
Impact Loads ◽  
Cohesive Element ◽  
Ice Loads ◽  
Ice Floes ◽  
The Time Domain ◽  
Contact Position ◽  
The Impact ◽  
Element Method

The existence of ice in ice-covered waters may cause damage to the propeller of polar ships, especially when massive ice floes are submerged around the hull. This paper aims to simulate an interaction process of a direct ice collision with a propeller based on the cohesive element method. A constitutive law is applied to model the ice material. The model of ice material is validated against model test results. The resulting impact loads acting on the contact surfaces and the corresponding ice block velocity are calculated in the time domain. The ice crushing, shearing and fracture failures are reproduced in the simulation. The convergence study with three meshing sizes of ice block is performed. To carry out a parametric study, five parameters are selected for analysis. These parameters are composed of rotational speed, direction of the propeller, initial speed of the ice block, contact position, and area between the ice and the propeller. The results show that the ice loads are affected by the five factors significantly. Ice loads tend to increase by decreasing the rotational speed, increasing the initial ice speed and the contact area, and changing the rotational direction from clockwise to counterclockwise. The effect of the contact position on the impact loads is relatively complex, depending on rotational speeds of the propeller.

Spatial Convergence of Crack Prediction on Structured Mesh Based on Distributed Cohesive Element Method

2012 ◽  
Vol 446-449 ◽  
pp. 3573-3577
Author(s):  
Ming Hua He ◽  
Ke Gui Xin ◽  
Ding Yu Cui ◽  
Yu Fei Liu
Keyword(s):  
Crack Path ◽  
Mesh Size ◽  
Cohesive Crack ◽  
Spatial Characteristic ◽  
Cohesive Element ◽  
The Real ◽  
Spatial Convergence ◽  
Structured Mesh ◽  
Structural Specimen ◽  
Element Method

We use the distributed cohesive element method to simulate the dynamic fracture in structural specimen and arbitrary crack path is predicted. The focus in on convergence of the cohesive crack path as an approximation of the real crack as the spatial characteristic mesh size h approaches zero. We propose the structured mesh is satisfactory in capturing the real crack shape as we refine the mesh because the crack Hausdorff distance converges. However, the length of cohesive crack path does not converge as the mesh is refined. There is a finite length deviation between predicted cohesive crack path and physically real crack path on structured mesh.

Simulating Ice-Sloping Structure Interactions With the Cohesive Element Method

2012 ◽  
Author(s):  
Wenjun Lu ◽  
Sveinung Løset ◽  
Raed Lubbad
Keyword(s):  
Cohesive Zone ◽  
Fracture Initiation ◽  
Cohesive Element ◽  
Cohesive Elements ◽  
Initial Stiffness ◽  
Initial Attempt ◽  
Zone Method ◽  
Mesh Dependency ◽  
Level Ice ◽  
Element Method

The major processes that occur when level ice interacts with sloping structures (especially wide structures) are the fracturing of ice and upcoming ice fragments accumulating around the structure. The cohesive zone method, which can simulate both fracture initiation and propagation, is a potential numerical method to simulate this process. In this paper, as one of the numerical methods based on the cohesive zone theory, the cohesive element-based approach was used to simulate both the fracturing and upcoming fragmentation of level ice. However, simulating ice and sloping structure interactions with the cohesive element method poses several challenges. One often-highlighted challenge is its convergence issue. As an initial attempt, the mesh dependency of the cohesive element method was alleviated by both creating a mesh with a crossed triangle pattern and utilizing a penalty method to obtain the initial stiffness for the intrinsic cohesive elements. Furthermore, two potential methods (i.e., introduction of a random ice field and bulk energy dissipation considerations) to alleviate the mesh dependency problem were evaluated and discussed. Based on a series of simulations with the different aforementioned methods and mesh sizes, the global ice load history is obtained. The horizontal load information is validated against the test results and previous simulation results. According to the comparison, the mesh objectivity alleviation with different approaches was discussed. As a preliminary demonstration, the results of one preliminary simulation are summarized, and the load contributions from different ice structure interaction phases are illustrated and discussed.

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