Related Experiment Video
Updated: Jan 24, 2026
03:57
Transverse Fracture of the Mouse Femur with Stabilizing Pin
Published on: December 29, 2021
4.1K
Complexity in phase transforming pin-jointed auxetic lattices
G W Hunt1, T J Dodwell2,3
1Department of Mechanical Engineering, University of Bath, Bath BA2 7AY, UK.
Proceedings. Mathematical, Physical, and Engineering Sciences
|May 21, 2019
Summary
This study reveals complex behavior in auxetic lattices, showing a transition between auxetic and non-auxetic states with varying stiffness. An emergent modulus describes the average stiffness during this nonlinear phase.
Area of Science:
- Materials Science
- Mechanical Engineering
- Solid Mechanics
Background:
- Auxetic materials exhibit negative Poisson's ratio, expanding laterally when stretched.
- Re-entrant structures are a common design for auxetic lattices.
- Modeling complex behaviors like large deformations and nonlinear transitions is crucial for material design.
Purpose of the Study:
- To investigate the complex equilibrium behavior of re-entrant auxetic lattices under large deformations.
- To analyze the nonlinear transition between auxetic and non-auxetic phases.
- To identify and describe an emergent modulus characterizing the average stiffness during this transition.
Main Methods:
- Analysis of re-entrant structures with pin-jointed members.
- Inclusion of large deformation theory.
- Investigation of nonlinear equilibrium behavior and local stiffness switching.
Main Results:
- Demonstrated complex equilibrium behavior and multiple switches between stable and unstable states.
- Observed both positive and negative local stiffnesses during the transition.
- Identified an emergent modulus describing average axial stiffness over the transitional phase.
Conclusions:
- Auxetic lattice modeling can be highly complex, especially under large deformations.
- A consistent emergent modulus can characterize the average stiffness of auxetic lattices during nonlinear phase transitions.
Related Concept Videos
02:33Lattice Centering and Coordination Number
11.4K
The structure of a crystalline solid, whether a metal or not, is best described by considering its simplest repeating unit, which is referred to as its unit cell. The unit cell consists of lattice points that represent the locations of atoms or ions. The entire structure then consists of this unit cell repeating in three dimensions. The three different types of unit cells present in the cubic lattice are illustrated in Figure 1.
Types of Unit Cells
Imagine taking a large number of identical...
Types of Unit Cells
Imagine taking a large number of identical...
11.4K
02:54Trends in Lattice Energy: Ion Size and Charge
26.6K
An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a compound is a measure of the strength of this attraction. The lattice energy (ΔHlattice) of an ionic compound is defined as the energy required to separate one mole of the solid into its component gaseous ions. For the ionic solid sodium chloride, the lattice energy is the enthalpy change of the process:
26.6K
01:12Bewley Lattice Diagram
1.5K
The Bewley lattice diagram, developed by L. V. Bewley, effectively organizes the reflections occurring during transmission-line transients. It visually represents how voltage waves propagate and reflect within a transmission line, making it easier to understand the complex interactions that occur.
1.5K
02:39Phase Transitions: Melting and Freezing
14.8K
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
14.8K
01:21Euler's Formula for Pin-Ended Columns
698
In structural engineering, the stability of columns under compressive axial loads is a critical consideration, described as buckling. A typical example involves a column PQ, which is pin-connected at both ends and subjected to a centric axial load F applied at one end, with a reaction force of F' = -F at the other end. Here, it is crucial to understand that when an applied load exceeds the critical load, buckling occurs as the system becomes unstable.
To calculate the critical load, envision...
To calculate the critical load, envision...
698
01:16Structural Joints: Synovial Joints
6.5K
Synovial joints are the most common type of joint in the body. A key structural characteristic for a synovial joint is the presence of a joint cavity. This fluid-filled space is where the articulating surfaces of the bones contact each other. Also, unlike fibrous or cartilaginous joints, the articulating bone surfaces at a synovial joint are not directly connected to each other with fibrous connective tissue or cartilage. This gives the bones of a synovial joint the ability to move smoothly...
6.5K