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1. 西北工业大学 航空学院, 西安 710072;
2. 阿克伦大学工程学院, 阿克伦 44325

Modeling and machanical properties of composite bionic suture joint structures
MAO Wei1 , WANG Wenzhi1 , HE Lijun1 , ZHANG Chao2
1. College of Aeronautics, Northwestern Polytechnical University, Xi'an 71007 ;
2. College of Engineering, The University of Akron, Akron 44325, US
Received: 2015-11-23; Accepted: 2016-01-08; Published online: 2016-01-28 15:15
Foundation item: National Natural Science Foundation of China (11502205)
Corresponding author. WANG Wenzhi, Tel.:029-88494855, E-mail:wangwenzhi@nwpu.edu.cn
Abstract: In this paper, we developed a parametric modeling framework for composite bionic suture joint structures through MATLAB and ABAQUS secondary development based on Python language. It shows the capability in describing the complicated suture joint geometry with different types of hierarchy and automatic generation of finite element mesh for mechanical modeling. Furthermore, interactions between geometric parameters (tooth angle, baseline type, and hierarchy) and structure performance are analyzed. The numerical results show that the bionic suture joint structure has better structural damage tolerance with the presence of a lower tooth angle, a sin curve baseline and a higher hierarchy. Through this work, parametric modeling of composite suture joint structure is realized, and the interaction among mechanical strength, damage mechanism and suture geometries is investigated, which provides meaningful guidelines for the design and optimization of novel high performance composite joint structures.
Key words: bionic suture joint structure     parametric modeling     finite element model     composites     cohesive element

1 骨缝齿接结构参数化建模 1.1 几何外形参数描述

 图 1 典型骨缝齿接结构示意图 Fig. 1 Schematic diagram of typical suture joint structure
1.2 基于分形原理与MATLAB的齿接结构几何构型表述

 图 2 几何构型表述程序流程图 Fig. 2 Program flowchart of geometric shape generation

GUI生成的几种不同分形结果如图 3所示，其中图 3(a)展示了基线类型为直线、层级为4、齿数为4的齿接结构示意图。

 图 3 GUI界面生成分形结果 Fig. 3 Fractal outline generated through GUI

1.3 基于Python语言的齿接结构参数化建模

Python是一种面向对象的脚本语言，它功能强大，既可以独立运行，也可以用作脚本语言，特别适用快速的应用程序开发[15]。本文对ABAQUS前处理进行二次开发，综合运用了MATLAB和Python语言控制ABAQUS的建模与装配过程。利用GUI，让用户方便地输入有关参数，得到各种所需的齿接结构并输出几何关键点坐标，然后通过Python语言编写前处理程序自动读取这些数据点坐标进行建模和装配，有效地解决了建模时的繁琐、易错等问题，提高了建模效率与精度。图 4所示为基于ABAQUS有限元分析软件构建的几种齿接结构有限元模型(FEM)。

 图 4 GUI生成的骨缝齿接结构有限元模型 Fig. 4 FEM of suture joint structure generated by GUI
2 复合材料齿接结构力学行为 2.1 齿接结构几何外形

 齿数 齿顶角/(°) 基线类型 层级 9 30 直线 1 9 45 直线 1 9 60 直线 1 15 45 直线 1 15 45 正弦曲线 1 5 45 直线 2 5 45 直线 3

2.2 有限元模型

 材料参数 弹性模量/MPa 泊松比 数值 116 000 0.3

 MPa 材料参数 Knn Kss Ktt 数值 491 000 264 500 264 500 注：Knn-法向刚度；Kss-1方向刚度；Ktt-2方向刚度。

 (1)
 (2)

 名义应力 法向 1方向 2方向 数值/MPa 55 30 30

2.3 结果分析及讨论

2.3.1 齿顶角的影响

 图 5 齿顶角不同的骨缝齿接结构载荷-位移曲线、等效应力-位移曲线 Fig. 5 Curves of load-displacement and equivalent stress-displacement for suture joint structure with different tooth angles

2.3.2 基线类型的影响

 图 6 不同基线类型骨缝齿接结构载荷-位移曲线、等效应力-位移曲线 Fig. 6 Curves of load-displacement and equivalent stress-displacement for suture joint structure with different baseline types

 图 7 不同基线类型骨缝齿接结构内聚力单元损伤过程 Fig. 7 Damage evolution of cohesive element for suture joint structure with different baseline types

2.3.3 层级的影响

 图 8 不同层级骨缝齿接结构应力分布、载荷-位移曲线 Fig. 8 Stress distribution and load-displacement curves for suture joint structure with different hierarchies

3 结论

1)低层级齿接结构的承载能力随着齿顶角度减小而增大，且齿间界面初始损伤首先发生在自由边位置。

2)当齿基线类型为正弦曲线时，结构由于自锁特性，使得承载能力明显提高。

3)对于高层级齿接结构，其结构强度及损伤容限由于界面自锁能力的提高而显著提升。

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#### 文章信息

MAO Wei, WANG Wenzhi, HE Lijun, ZHANG Chao

Modeling and machanical properties of composite bionic suture joint structures

Journal of Beijing University of Aeronautics and Astronsutics, 2016, 42(12): 2762-2768
http://dx.doi.org/10.13700/j.bh.1001-5965.2015.0772