今日更新:International Journal of Solids and Structures 1 篇,Journal of the Mechanics and Physics of Solids 1 篇,Thin-Walled Structures 2 篇
The peeling behavior of a heterogeneous elastic film on a rigid substrate
Yin Hanbin, Peng Zhilong, Chen Shaohua
doi:10.1016/j.ijsolstr.2023.112529
刚性基底上异质弹性薄膜的剥离行为
Although the interfacial peeling behavior of a homogeneous film-substrate system is well understood, the peeling process of a heterogeneous elastic film bonded to a rigid substrate is still unclear. In the present paper, the peeling behavior of a heterogeneous film adhering on a rigid substrate under a vertical peeling force is investigated theoretically, in which the film’s heterogeneity is characterized by the change of bending stiffness along the length of the film. Based on the principle of minimum potential energy, the typical relationship between the peeling force and the peeling displacement during the whole peeling process is achieved. Different from the homogeneous film case, the peeling force can be regulated dramatically by the film’s heterogeneous bending stiffness during the peeling process. When the interfacial debonding front propagates from a compliant segment to a stiff segment, the peeling force is enhanced; while the peeling force is weakened as the interfacial debonding front goes from a stiff segment to a compliant one. The enhancement or weakening of the peeling force depends not only on the bending stiffness of each segment of the film but also on the bending stiffness ratio of neighboring segments, as well as the adhesion length of each segment and the interfacial adhesion properties. The mechanism underlying the heterogeneity-induced tunable peeling force is further elucidated by the change rate of elastic bending energy stored in the film and energy overcoming the interfacial interaction potential during the peeling process. The transfer and redistribution of the elastic bending energy are the main factors that induce the change of peeling force as the interfacial debonding front reaches the boundary of neighboring segments with different bending stiffness. The results of this paper can provide a new strategy for designing film-substrate systems with adjustable adhesion without changing the interfacial characteristics.
虽然对同质薄膜-基底系统的界面剥离行为已经有了很好的理解,但对粘附在刚性基底上的异质弹性薄膜的剥离过程仍不清楚。本文从理论上研究了粘附在刚性基底上的异质薄膜在垂直剥离力作用下的剥离行为。根据最小势能原理,得到了整个剥离过程中剥离力与剥离位移之间的典型关系。与均质薄膜的情况不同,在剥离过程中,薄膜的异质弯曲刚度可以极大地调节剥离力。当界面脱粘前沿从顺应段传播到刚性段时,剥离力增强;而当界面脱粘前沿从刚性段传播到顺应段时,剥离力减弱。剥离力的增强或减弱不仅取决于薄膜每个区段的弯曲刚度,还取决于相邻区段的弯曲刚度比,以及每个区段的粘附长度和界面粘附特性。在剥离过程中,储存在薄膜中的弹性弯曲能和克服界面相互作用势能的能量的变化率进一步阐明了异质性诱导的可调剥离力的机理。当界面脱粘前沿到达具有不同弯曲刚度的相邻片段的边界时,弹性弯曲能的转移和再分配是引起剥离力变化的主要因素。本文的研究结果为在不改变界面特性的情况下设计粘附力可调的薄膜-基底系统提供了一种新策略。
Complementing a continuum thermodynamic approach to constitutive modeling with symbolic regression
Garbrecht Karl, Birky Donovan, Lester Brian, Emery John, Hochhalter Jacob
doi:10.1016/j.jmps.2023.105472
用符号回归对连续热力学方法进行构型建模的补充
An interpretable machine learning method, physics-informed genetic programming-based symbolic regression (P-GPSR), is integrated into a continuum thermodynamic approach to developing constitutive models. The proposed strategy for combining a thermodynamic analysis with P-GPSR is demonstrated by generating a yield function for an idealized material with voids, i.e., the Gurson yield function. First, a thermodynamic-based analysis is used to derive model requirements that are exploited in a custom P-GPSR implementation as fitness criteria or are strongly enforced in the solution. The P-GPSR implementation improved accuracy, generalizability, and training time compared to the same GPSR code without physics-informed fitness criteria. The yield function generated through the P-GPSR framework is in the form of a composite function that describes a class of materials and is characteristically more interpretable than GPSR-derived equations. The physical significance of the input functions learned by P-GPSR within the composite function is acquired from the thermodynamic analysis. Fundamental explanations of why the implemented P-GPSR capabilities improve results over a conventional GPSR algorithm are provided.
将一种可解释的机器学习方法--基于物理信息的遗传编程符号回归(P-GPSR)--集成到连续热力学方法中,以开发构成模型。通过生成理想化空隙材料的屈服函数(即 Gurson 屈服函数),展示了将热力学分析与 P-GPSR 结合起来的拟议策略。首先,基于热力学的分析用于推导模型要求,这些要求在定制的 P-GPSR 实现中作为合适度标准加以利用,或在解决方案中强制执行。P-GPSR 实现与没有物理信息适配标准的相同 GPSR 代码相比,提高了准确性、通用性和训练时间。通过 P-GPSR 框架生成的产量函数采用复合函数的形式,描述了一类材料,与 GPSR 衍生方程相比,具有更强的可解释性。P-GPSR 在复合函数中学习的输入函数的物理意义来自热力学分析。本文从根本上解释了为什么 P-GPSR 的实施能力比传统 GPSR 算法的结果更好。
Origami embedded honeycomb with three-axial comparable and improved energy absorption performance
Wang Zhonggang, Yao Shaocheng, Liu Kai, Wei Kai, Gao Tianyu, Zhao Minquan
doi:10.1016/j.tws.2023.111295
具有三轴可比性和更佳能量吸收性能的折纸嵌入式蜂窝结构
Origami has been exploited to various marvelous materials to manifest mechanical properties. In this study, inspired by the distinctive deformation modes of kresling-origami with rotation limitation, a design strategy of embedding kresling-origami into conventional honeycomb for improving energy absorption capacity is proposed. According to different embedding approaches, i.e., replacing or adding cell walls, two types of origami-embedded honeycombs are constructed. To investigate the energy absorption properties of proposed origami-embedded honeycombs, 3D-printed specimens are manufactured and tested under quasi-static compression. The experiment results show that proposed origami-embedded honeycomb have higher specific energy absorption and three-axial comparable energy absorption performance relative to conventional ones. It indicates the design strategy of embedding kresling-origami is practical for improving energy absorption capacity of conventional honeycomb and weakening its anisotropy. In addition, the energy absorption performance of origami-embedded honeycombs with different geometrical configurations is investigated through an established and experimentally validated numerical simulation model. Furthermore, the mechanism (i.e., high energy-absorbing deformation modes of kresling-origami under boundary constraints) of embedding design strategy is clarified via comparison analysis between experiments and simulations. This strategy carves out a novel way to optimize the mechanical properties of honeycomb and may inspire new innovations of metamaterials.
折纸已被运用到各种神奇的材料中,以体现其机械特性。本研究受克雷林折纸具有旋转限制的独特变形模式的启发,提出了在传统蜂窝中嵌入克雷林折纸以提高能量吸收能力的设计策略。根据不同的嵌入方法,即替换或添加细胞壁,构建了两种类型的折纸嵌入蜂窝。为了研究拟议的纸黏土蜂窝的能量吸收特性,制作了三维打印试样,并在准静态压缩条件下进行了测试。实验结果表明,与传统蜂窝相比,拟议的折纸嵌入蜂窝具有更高的比能量吸收和三轴可比能量吸收性能。这表明嵌入克雷斯林-折纸的设计策略对于提高传统蜂窝的能量吸收能力和削弱其各向异性是切实可行的。此外,还通过建立并经实验验证的数值模拟模型,研究了不同几何构型的折纸嵌入蜂窝的能量吸收性能。此外,通过实验和模拟的对比分析,阐明了嵌入设计策略的机理(即在边界约束条件下克雷斯林-折纸的高能量吸收变形模式)。该策略为优化蜂窝材料的力学性能开辟了一条新途径,并可能为超材料的创新带来启发。
A new analytical approach for nonlinear thermo-mechanical postbuckling of FG-GPLRC circular plates and shallow spherical caps stiffened by spiderweb stiffeners
Nam Vu Hoai, Minh Tran Quang, Hieu Pham Thanh, Hung Vu Tho, Tu Bui Tien, Hoai Nguyen Thi Thanh, Dong Dang Thuy
doi:10.1016/j.tws.2023.111296
FG-GPLRC 圆板和蛛网加强筋加固的浅球形盖非线性热机械后屈曲的新分析方法
For the first time, the problem of nonlinear postbuckling of circular plates and shallow spherical caps reinforced by meridian, parallel stiffeners, and spiderweb stiffeners based on the Donnell shell theory (DST) and von Kármán geometric nonlinearities is presented. The caps/plates and stiffeners are made from functionally graded graphene platelet-reinforced composite (FG-GPLRC). These stiffened structures are subjected to uniformly distributed external pressure or/and uniformly distributed thermal loads and are rested on a nonlinear elastic foundation. By expanding Lekhnitskii's smeared stiffener technique and employing the Ritz method of energy, the formulas to determine the postbuckling curves of the external pressure–deflection and thermal load-deflection relations of stiffened plates/spherical caps are derived. Meaningful discussions of the various influences of FG-GPLRC stiffeners, material distributions of plate/cap and stiffeners, and geometrical, material, and foundation parameters are shown in the content of the numerical investigations.
本文首次提出了基于唐奈壳理论(DST)和 von Kármán 几何非线性的圆板和由经线、平行加劲件和蛛网加劲件加固的浅球形帽的非线性后屈曲问题。盖/板和加强筋由功能分级石墨烯血小板增强复合材料(FG-GPLRC)制成。这些加劲结构承受均匀分布的外部压力或/和均匀分布的热负荷,并固定在非线性弹性基础上。通过扩展 Lekhnitskii 的涂抹加劲技术并采用里兹能量法,得出了加劲板/球形盖外部压力-挠度和热负荷-挠度关系的后屈曲曲线公式。在数值研究内容中,对 FG-GPLRC 加劲件、板/帽和加劲件的材料分布以及几何、材料和地基参数的各种影响进行了有意义的讨论。