Structural Metamaterials: Session I
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS Structural Materials Division, TMS: Additive Manufacturing Committee, TMS: Mechanical Behavior of Materials Committee
Program Organizers: Amy Wat, Lawrence Livermore National Laboratory; Brad Boyce, Sandia National Laboratories; Xiaoyu Zheng, University of California, Los Angeles; Fabrizio Scarpa, University of Bristol; Robert Ritchie, University of California, Berkeley
Monday 8:30 AM
February 28, 2022
Room: 304A
Location: Anaheim Convention Center
8:30 AM
Bioinspired Hierarchical Architected Structures Via Additive Manufacturing: Ali Afrouzian1; Amit Bandyopadhyay1; 1Washington State University
Natural materials featuring hierarchical microstructures often show remarkable mechanical properties such as compressive strength and higher impact resistance. Functionally graded materials (FGMs) have been fabricated using direct energy deposition (DED)-based additive manufacturing (AM) technique to mimic natural structures such as bone and nacre. To this end, we represent a layered metallic structure including commercially pure Titanium (CPTi) and Nickel (Ni) which is not achievable by conventional manufacturing approaches. Mechanical characterizations, microstructure, Vickers hardness (HV), and compression tests have been performed to understand the influence of reactive interphase on the bulk material’s performance.
8:50 AM
Phase Field Modeling of Crack Propagation, Deflection and Delamination in Engineered Interfaces: Vinamra Agrawal1; Brandon Runnels2; 1Auburn University; 2University of Colorado at Colorado Springs
Nanolayered composites with engineered interfaces offer excellent potential for damage resistance and improved fracture toughness. In this work, we use phase field model to study the crack propagation in nanolayered composites with engineered interfaces. We study the case of a notch crack propagating under mode-I loading. The domain comprised of two isotropic materials with different elastic properties and fracture energies, with an interface of a different fracture energy. As the crack propagates and approaches the interface, depending on the moduli, fracture energy ratios and geometry of the interface, the crack can either deflect towards or away from the interface leading to either delamination or material fracture. We implement the phase field model using Alamo, a finite difference multilevel multigrid and multicomponent solver, on a block structured adaptively refined grid. We conduct a systematic analysis of crack interaction with interface by varying moduli, fracture energies and interface geometries.
9:10 AM
Seeing Beneath the Surface: Estimating Interior Material Properties with Visual Vibration Tomography: Berthy Feng1; Alexander Ogren1; Chiara Daraio1; Katherine Bouman1; 1Caltech
An object’s interior material properties, while invisible to the human eye, determine motion observed on its surface. We propose an approach that estimates spatially-varying material properties of an object directly from a monocular video of its surface vibrations. Specifically, we estimate Young’s modulus and density throughout a 3D object with known geometry. Vibration analysis tools such as laser vibrometers, ultrasound detectors, and other contact sensors generally do not recover full-field measurements. Our work shows how to overcome such limitations, imaging full-field material properties from 2D surface displacements captured in a monocular video. Our approach is to (1) measure sub-pixel motion and decompose this motion into image-space modes, and (2) directly infer Young’s modulus and density values by solving a constrained optimization problem. We demonstrate our approach on both simulated and real videos. In particular, our method allows us to characterize unseen defects on a drum head from real, high-speed video.
9:30 AM Cancelled
Temperature and Stress-induced Recovery in Artificial Shape Memory Alloys: Yunlan Zhang1; Mirian Velay1; David Restrepo2; Nilesh Mankame3; Pablo Zavattieri1; 1Purdue University; 2University of Texas, San Antonio; 3General Motors Global Research & Development
We analyzed a new family of architected materials that are capable mimiking both salient behaviors exhibited by shape memory alloys namely, superelasticity and the shape memory effect. Unlike thermal bimorphs, which rely on differential thermal expansion, and shape memory polymer based structures, which rely on changes in the macromolecular structure of the constituent polymers, the proposed design exploits the temperature dependence of the two constituent base materials as well as the thermomechanics of the building block's structure to reproduce the behavior of shape memory alloys. We develop an analytical model that explains how the block works. This model is then used to generate a phase diagram that captures the complex relationship between the stress on the material, its temperature and the various phases that can be produced. We then develop a design space map that enables a material designer to select key material parameters based on a desired thermo-mechanical behavior.