scholarly journals A nonlinear mechanics model of bio-inspired hierarchical lattice materials consisting of horseshoe microstructures

2016 ◽  
Vol 90 ◽  
pp. 179-202 ◽  
Author(s):  
Qiang Ma ◽  
Huanyu Cheng ◽  
Kyung-In Jang ◽  
Haiwen Luan ◽  
Keh-Chih Hwang ◽  
...  
Keyword(s):  
Nonlinear Mechanics ◽  
Hierarchical Lattice ◽  
Mechanics Model ◽  
Lattice Materials

Design of composite lattice materials combined with fabrication approaches

2018 ◽  
Vol 53 (3) ◽  
pp. 393-404 ◽  
Author(s):  
Jun Xu ◽  
Yaobo Wu ◽  
Xiang Gao ◽  
Huaping Wu ◽  
Steven Nutt ◽  
...  
Keyword(s):  
Shear Strength ◽  
Mechanical Performance ◽  
Analytical Models ◽  
Core Material ◽  
Foam Core ◽  
Hierarchical Lattice ◽  
Bottom Up ◽  
Lattice Materials ◽  
Assembly Technique ◽  
Composite Lattice

Lattice materials can be designed through their microstructure while concurrently considering fabrication feasibility. Here, we propose two types of composite lattice materials with enhanced resistance to buckling: (a) hollow lattice materials fabricated by a newly developed bottom-up assembly technique and the previously developed thermal expansion molding technique and (b) hierarchical lattice materials with foam core sandwich trusses fabricated by interlocking assembly process. The mechanical performance of sandwich structures featuring the two types of lattice cores was tested and analyzed theoretically. For hollow lattice core material, samples from two different fabrication processes were compared and both failed by nodal rupture or debonding. In contrast, hierarchical lattice structures failed by shear buckling without interfacial failure in the sandwich struts. Calculations using established analytical models indicated that the shear strength of hollow lattice cores could be optimized by judicious selection of the thickness of patterned plates. Likewise, the shear strength of hierarchical foam core truss cores could be maximized (with minimal weight) through design of truss geometry. The bottom-up assembly technique could provide a feasible way for mass production of lattice cores, but the design about how to assembly is critical. Hierarchical lattice cores with foam sandwich trusses should be a suitable choice for future lightweight material application.

Discovering Sequenced Origami Folding Through Nonlinear Mechanics and Topology Optimization

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Andrew S. Gillman ◽  
Kazuko Fuchi ◽  
Philip R. Buskohl
Keyword(s):  
Topology Optimization ◽  
Design Space ◽  
Optimization Algorithms ◽  
Element Model ◽  
Evolutionary Optimization ◽  
Nonlinear Mechanics ◽  
Design Problems ◽  
Mechanics Model ◽  
Highly Nonlinear ◽  
Evolutionary Optimization Algorithms

Origami folding provides a novel method to transform two-dimensional (2D) sheets into complex functional structures. However, the enormity of the foldable design space necessitates development of algorithms to efficiently discover new origami fold patterns with specific performance objectives. To address this challenge, this work combines a recently developed efficient modified truss finite element model with a ground structure-based topology optimization framework. A nonlinear mechanics model is required to model the sequenced motion and large folding common in the actuation of origami structures. These highly nonlinear motions limit the ability to define convex objective functions, and parallelizable evolutionary optimization algorithms for traversing nonconvex origami design problems are developed and considered. The ability of this framework to discover fold topologies that maximize targeted actuation is verified for the well-known “Chomper” and “Square Twist” patterns. A simple twist-based design is also discovered using the verified framework. Through these case studies, the role of critical points and bifurcations emanating from sequenced deformation mechanisms (including interplay of folding, facet bending, and stretching) on design optimization is analyzed. In addition, the performance of both gradient and evolutionary optimization algorithms are explored, and genetic algorithms (GAs) consistently yield solutions with better performance given the apparent nonconvexity of the response-design space.

The Mechanical Properties of Hierarchical Truss-Walled Lattice Materials

2017 ◽  
Vol 09 (02) ◽  
pp. 1750027 ◽  
Author(s):  
Fangfang Sun ◽  
Qing Zheng ◽  
Hualin Fan ◽  
Daining Fang
Keyword(s):  
Mechanical Properties ◽  
Lattice Structure ◽  
Wall Structure ◽  
Lattice Structures ◽  
Mechanical Behaviors ◽  
Hierarchical Lattice ◽  
Buckling Stress ◽  
Lattice Materials ◽  
Buckling Resistance ◽  
Theoretical Analyses

To construct a hierarchical lattice structure (HLS), truss wall is introduced into ordinary lattice structure (OLS). Young’s modulus, yield strength and buckling stress of HLSs were evaluated theoretically. Failure maps of different HLSs were plotted and compared based on the theoretical analyses. It is indicated that mechanical behaviors of hexagonal HLSs made of triangular lattice walls can be greatly enhanced by the hierarchical wall structure, while properties of triangular HLSs are weakened, except the anti-buckling resistance. When HLSs are made of bending-dominated honeycomb walls, their properties will be reduced, indicating that hierarchical structure should be appropriately designed to make ultra-light structures benefit from this construction. This viewpoint is strengthened by the discussions on the performances of high order lattice structures, where only bending-dominated HLSs with stretching-dominated lattice wall benefit from the hierarchy.

scholarly journals Theoretical and Numerical Analysis of Blasting Pressure of Cylindrical Shells under Internal Explosive Loading

2021 ◽  
Vol 9 (11) ◽  
pp. 1297
Author(s):  
Zhan-Feng Chen ◽  
Hui-Jie Wang ◽  
Zhiqian Sang ◽  
Wen Wang ◽  
He Yang ◽  
...  
Keyword(s):  
Mechanical Model ◽  
Dynamic Pressure ◽  
Cylindrical Shells ◽  
Solution Process ◽  
Blast Loading ◽  
Nonlinear Mechanics ◽  
Pressure Equation ◽  
Blast Pressure ◽  
Mechanics Model ◽  
Internal Blast Loading

Cylindrical shells are principal structural elements that are used for many purposes, such as offshore, sub-marine, and airborne structures. The nonlinear mechanics model of internal blast loading was established to predict the dynamic blast pressure of cylindrical shells. However, due to the complexity of the nonlinear mechanical model, the solution process is time-consuming. In this study, the nonlinear mechanics model of internal blast loading is linearized, and the dynamic blast pressure of cylindrical shells is solved. First, a mechanical model of cylindrical shells subjected to internal blast loading is proposed. To simplify the calculation, the internal blast loading is reduced to linearly uniform variations. Second, according to the stress function method, the dynamic blast pressure equation of cylindrical shells subjected to blast loading is derived. Third, the calculated results are compared with those of the finite element method (FEM) under different durations of dynamic pressure pulse. Finally, to reduce the errors, the dynamic blast pressure equation is further optimized. The results demonstrate that the optimized equation is in good agreement with the FEM, and is feasible to linearize the internal blast loading of cylindrical shells.

Effects of architecture level on mechanical properties of hierarchical lattice materials

2019 ◽  
Vol 157-158 ◽  
pp. 282-292 ◽  
Author(s):  
Sha Yin ◽  
Haoyu Chen ◽  
Jiani Li ◽  
T.X. Yu ◽  
Jun Xu
Keyword(s):  
Mechanical Properties ◽  
Hierarchical Lattice ◽  
Lattice Materials

The Safety Status Evaluation of Rock Mass Element by Nonlinear Mechanics Model

2012 ◽  
Vol 193-194 ◽  
pp. 675-678
Author(s):  
Hai Bo Zhang ◽  
Qun Yi Liu
Keyword(s):  
Rock Mass ◽  
Safety Factor ◽  
Rock Strength ◽  
Soil Mass ◽  
Nonlinear Mechanics ◽  
Real Situation ◽  
Mechanics Model ◽  
Mass Element ◽  
Main Index ◽  
The Stability

Slope stability analysis is an important content in geotechnical engineering designing. And the safety factor is still the main index to evaluate the safety status of the whole slope, but the stability of each element of rock mass can not be reflected by the whole safety factor. Some scholars introduce the concept of point safety factor (PSF) to evaluate the stability of each element in rock-soil mass. However, the present work about PSF is remaining in the field of linear model, instead of nonlinear model. But in real situation, the nonlinear failure criterions are more adaptable used to describe the characteristic of rock mass, such as nonlinear failure characteristic of rock strength, structural characteristic and the effect of the stress to the strength of rock mass. So in this paper, the PSF based on the Hoek-Brown nonlinear mechanics model is founded, followed by calculation PSF for one rock mass element stability.

Interlocked hierarchical lattice materials reinforced by woven textile sandwich composites

2013 ◽  
Vol 87 ◽  
pp. 142-148 ◽  
Author(s):  
Hualin Fan ◽  
Fangfang Sun ◽  
Lin Yang ◽  
Fengnian Jin ◽  
Dajuan Zhao
Keyword(s):  
Sandwich Composites ◽  
Hierarchical Lattice ◽  
Lattice Materials ◽  
Woven Textile

The Research Nonlinear Mechanics for Non-Backlash Output Mechanism of Precision Ball Planetary Drive

2013 ◽  
Vol 387 ◽  
pp. 90-93
Author(s):  
Zi Jun An ◽  
Zuo Mei Yang ◽  
Li Ying Duan
Keyword(s):  
Computer Program ◽  
Contact Force ◽  
Theoretical Basis ◽  
Three Dimension ◽  
Nonlinear Mechanics ◽  
Force Analysis ◽  
Ring Groove ◽  
Numerical Example ◽  
Mechanics Model ◽  
Planetary Transmission

Precision ball planetary drive is mainly composed of non-backlash cycloid ball reduction speed mechanism and non-backlash ball ring groove equal speed output mechanism (NBRGEO mechanism or called W mechanism). The three-dimension contact force is analyzed. The nonlinear mechanics model of NBRGEO mechanism was established. The formulas of contact force and stress were deduced. A numerical example is intended to illustrate the presented method of contact force analysis by using of computer program. Therefore, the contact force and stress distributing characteristics of NBRGEO mechanism is acquired. The research results offer theoretical basis for the design of NBRGEO mechanism of the precision ball planetary drive and the research of other precision planetary transmission.

Discovering Origami Fold Patterns With Optimal Actuation Through Nonlinear Mechanics Analysis

2017 ◽  
Author(s):  
Andrew Gillman ◽  
Kazuko Fuchi ◽  
Giorgio Bazzan ◽  
Edward J. Alyanak ◽  
Philip R. Buskohl
Keyword(s):  
Topology Optimization ◽  
Optimization Algorithms ◽  
Three Dimensional ◽  
Nonlinear Mechanics ◽  
Optimization Framework ◽  
Mechanics Model ◽  
Truss Model ◽  
Gradient Optimization ◽  
Large Rotations ◽  
Mechanical Actuation

The ability of origami fold patterns to transform two-dimensional sheets into complex three-dimensional structures provides utility for design and development of multifunctional devices. Recently, a topology optimization framework has been developed to discover fold patterns that realize optimal performance including mechanical actuation. This work incorporates an efficient nonlinear mechanics model into the topology optimization framework that accurately captures the geometric non-linearities associated with large rotations of origami facets. A nonlinear truss model, with accommodation for fold stiffness and large rotations, is implemented in both gradient and non-gradient optimization algorithms in this study. The ability of this framework to discover fold topology maximizing actuation motion is verified for the well known “Chomper” and “Square Twist” patterns. In particular, the performance of various optimization algorithms is discussed, and genetic algorithms consistently yield solutions with better performance.

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