Dynamic Behavior of Materials IX: On-Demand Oral Presentations
Sponsored by: TMS Structural Materials Division, TMS: Mechanical Behavior of Materials Committee
Program Organizers: Eric Brown, Los Alamos National Laboratory; Saryu Fensin, Los Alamos National Laboratory; George Gray, Los Alamos National Laboratory; Marc Meyers, University of California, San Diego; Neil Bourne, University of Manchester; Avinash Dongare, University of Connecticut; Benjamin Morrow, Los Alamos National Laboratory; Cyril Williams, US Army Research Laboratory
Monday 8:00 AM
March 14, 2022
Room: Mechanics & Structural Reliability
Location: On-Demand Room
Modeling Hypervelocity Impacts in Additively Manufactured Interpenetrating Composites: Jason Allen1; Jiahao Cheng1; Xiaohua Hu1; Derek Splitter1; Amit Shyam1; 1Oak Ridge National Laboratory
Additively Manufactured Interpenetrating Composites (AMIPCs) are metal-metal chain composite in development for use in high energy absorption systems. The reinforcing phase is comprised of 316L austenitic stainless-steel that is additively manufactured in continuous lattice configurations while the matrix phase is comprised of A356 aluminum-silicon casting alloy which is cast into the reinforcing phase. Previous work has shown that AMIPCs have excellent spall resistance under hypervelocity impact conditions over monolithic equivalents of either material alone or in bi-layer form. In this work, Finite Element Analysis (FEA) is used to investigate the energy absorption mechanism of AMIPCs under hypervelocity impact conditions. Model performance is evaluated with respect to prior measurements and parametric studies are undertaken to further evaluate performance as a function of composite volume fraction, structure, and interface. The outcome provides insight into material design criteria and performance predictions for hybrid metallic material systems with exceptional dynamic damage tolerance.
Energy Balance of Rapidly Deforming Foam Filled Cylindrical Shells in a High Pressure Fluid Environment: Carlos Javier1; Shyamal Kishore2; Koray Senol3; Arun Shukla2; 1US Naval Undersea Warfare Center; 2University of Rhode Island; 3Edwards Lifesciences
This study aims to mitigate the high-pressure spikes generated in underwater implosions. Experiments were performed underwater in a pressure vessel, where thin-walled aluminum 6061 cylindrical shells were placed, and the hydrostatic pressure was increased until the tubes collapsed. To mitigate the pressure pulses radiated into the fluid by the implosion of the tubes, closed cell PVC foam rods of varying densities were placed concentrically inside of the aluminum tubes. Digital Image Correlation was employed to obtain the full-field displacements of the aluminum tubes during implosion. The pressure fields created during the structural collapse were recorded with tourmaline pressure sensors. The foam rods were able to decrease the peak pressure generated by a substantial amount. Fully coupled Fluid-Structure Interaction Finite Element models were created using the Abaqus software to obtain the structural deformation energy in the aluminum tubes after implosion, as well as the energy absorbed by the foam rods.
Multi-fidelity Machine Learning Based Approach to Predict Local Strain Response: Tyler Dillard1; Nolan Lewis1; Abhijeet Dhiman1; Vikas Tomar1; 1Purdue University
High strain dynamic response of materials is of key importance for material development. Of particular interest is modeling and predicting the wave propagation within a material in response to high impact forces. PMMA(Polymethyl Methacrylate) samples were subjected to flat nail impacts at high velocities using an in-house built table-top gas gun. Sensors (force sensitivity resistors) were used to measure the material load response of examined samples. Digital Image Correlation (DIC) was used with a high-speed camera to record the local surface deformation and strain field. The use of an FEM simulation enabled the ability to produce large amounts of high through-put data to produce a data set for a low fidelity model. The model predicts the strain profile (DIC data) of the target material (PMMA) during dynamic impact. Composite neural-net architecture is implemented to model a multi-fidelity approach and comparisons were made between low-fidelity, high-fidelity, and multi-fidelity predictions.
In Situ X-ray Diffraction of Sapphire Single Crystals during Laser Compression and Release: Anirudh Hari1; Saransh Singh2; Joel Bernier2; Rohit Hari1; Raymond Smith2; Thomas Duffy3; Todd Hufnagel1; June Wicks1; 1Johns Hopkins University; 2Lawrence Livermore National Laboratory; 3Princeton University
Sapphire is an important earth mineral notable for its high compressive strength and hardness. Molecular dynamics simulations find that sapphire shocked to 150 GPa deforms via basal slip and rhombohedral twinning along the {102} family of planes (Kuksin & Yanilkin 2012). In this work, we describe laser-driven shock compression experiments on a-cut and c-cut sapphire to 150 GPa at the Matter in Extreme Conditions endstation of the Linac Coherent Light Source. Ultrafast x-ray pulses (50 fs, 10^12 photons/pulse) were used to probe the shock response as a function of time, measuring in situ lattice-level response during shock propagation and release. We see evidence of plastic deformation and crystal break-up during compression. After release to ambient pressure, we observe change from large single-crystal spots to a powder texture, indicating further break-up. We will compare and discuss the effects of different orientations and release paths on crystallographic texture.
High Strain Rate Atomistic and Mesoscale Simulations of Ejecta Jet Formation in Cu and Sn Systems: Probing Initial Conditions for Ejecta Jet Formation: Marco Echeverria1; Sergey Galitskiy1; Alison Saunders2; Tomorr Haxhimali2; Robert Rudd2; Faddy Najjar2; Avinash Dongare1; 1University Of Connecticut; 2Lawrence Livermore National Laboratory
The detailed microphysics that entails the formation of ejecta jets is difficult to observe experimentally due to the small length- and time-scales inherent to the process. Material effects and slight variations on a material's free surface significantly affect jet properties. We carry out large-scale molecular dynamics and mesoscale simulations to understand the evolution of microstructure on the formation of ejecta jets due to the interaction of shock waves with surface perturbations in Cu and Sn. The loading conditions are chosen to generate shock pressures ranging from 16 GPa to 100 GPa. We demonstrate the effect of varying the crystal orientation and structure on the ejecta jet's morphology and properties (velocity, temperature, inner pressure). LLNL-ABS-824451. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and supported by Laboratory Directed Research and Development (LDRD) Grant No. 18-ERD-060.
In-situ Shock Stress Field Detection Using Laser Array Raman Spectroscopy: Abhijeet Dhiman1; Nolan Lewis1; Vikas Tomar1; 1Purdue University
Time-gated Raman spectroscopy has been used in the past for chemical analysis at a nanosecond time scale. Based on prior calibration, the Raman spectra can be used to predict local stress on a microscale spot size. In this work, we used a unique setup where multi-spot Raman spectra were obtained over a microstructure using laser array spots on the sample. The excited Raman signal from each spot on the array was collected into a two-dimensional array of optical fibers for simultaneous spectrum analysis by a spectrograph. This technique was used to measure shock wave propagation through a microstructure of polymer bonded sugar at strain rates higher than 10^6/s. The study shows the effects of partial melting of sugar crystals due to shock compression and interparticle interactions.
Effect of Microstructure and Strain-rate on the Out-of-plane Compressive Response of UHMWPE Composites: Jason Parker1; KT Ramesh1; 1Johns Hopkins University
We study the microstructure evolution of UHMWPE (Ultra-High Molecular Weight Polyethylene) composites during dynamic loading. DyneemaŽ laminates are consolidated at multiple pressures, the microstructure is characterized with micro X-ray Computed Tomography CT (micro CT), and they are tested in uniaxial out-of-plane compression at strain rates ranging from 10-3 s-1 - 103 s-1 while simultaneously capturing the deformation history with high speed video. Image analysis is performed on the resulting high-speed video to measure the lateral deformation of the specimen. Combined with the axial deformation history, obtained from the Kolsky bar, we obtain the complete deformation gradient. Using a finite deformation formulation, we calculate volume change as a function of time and relate this to microstructure evolution in the specimen. This technique is used to study the influence and evolution of microstructure on UHMWPE composites loaded at strain-rates up to 3000 s-1.
Exploring the Spall Strength of the Interface of Additively Manufactured GRCop-84 and Inconel 625 Bimetallics: Andrew Boddorff1; Sungwoo Jang1; Gregory Kennedy1; Naresh Thadhani1; 1Georgia Institute of Technology
The strength of metallurgically bonded planar interfaces between additively manufactured (AM) GRCop-84 – Inconel 625 bimetals is investigated. The baseline dynamic tensile (spall) behavior of the monolithic parent materials is determined by plate-on-plate impact experiments employing multiple PDV probes. Bimetallic samples with either normal or inclined interfaces show a diverse range of responses between and within each experiment, due to differences in wave propagation characteristics. The responses include failure along a single uniform or irregular interface plane, or in three distinct material regions. The resulting values of the spall and interface failure strengths are distinctly different and correspond to those of the Inconel 625, GRCop-84, and the interface. The results provide a unique method for probing the dynamic failure strength of bimetal interfaces and spall strength of the respective metals in the same experiment.
Dynamic Non-equilibrium Plastic Flow of Metals under Rapid Heating: Steven Mates1; 1Nist
Metals that are heated to temperatures high enough to cause their microstructures to evolve, via dissolving or growing precipitates or wholesale phase transformations, may exhibit non-equilibrium mechanical behavior if the heating-plus-deformation time is short, but of the same order as, the transformation time. A rapidly-heated Kolsky Bar method is used to study this type of non-equilibrium behavior and to explore the possible influences on dynamic, plastic events where temperatures may exceed transformation thresholds by adiabatic and frictional heating but where heating and cooling rates are extremely high. Examples of non-equilibrium dynamic flow stress are presented for AISI 1045 carbon steel, aluminum alloy 6061-T6 and 17-4 PH (precipitation-hardenable) stainless steel. Details of the experimental method are discussed, and heating rate limitations for our compression and tension Kolsky bar setups are explored.
Accelerating and Supersonic Dislocation in Metals under Extreme Conditions: Daniel Blaschke1; Khanh Dang1; Saryu Fensin1; Jie Chen2; Benjamin Szajewski3; Darby Luscher1; 1Los Alamos National Laboratory; 2N/A (formerly Los Alamos National Laboratory); 3United States Army Research Laboratory
Understanding dislocation mobility is key to understanding material strength: how materials deform and the energy required to do so. An important unsolved question in this regard is whether dislocations can accelerate to supersonic speeds in metals. Previous molecular dynamics (MD) simulations in cubic crystals have indicated that supersonic motion may be possible in some cases. Our own work continues this endeavor for new crystal geometries using both MD and theory for an improved understanding. In this talk we present recent results, both analytic and from MD simulations, that elucidate high speed dislocation motion in single crystal metals under various conditions.
High Strain Rate Fracture Properties of Additively Manufactured Stainless Steel: Kevin Lamb1; Katie Koube2; Suresh Babu3; Josh Kacher2; Naresh Thadhani2; 1CNS Y12 / University of Tennessee; 2Georgia Institute of Technology; 3University of Tennessee
Evaluating the mechanical properties of parts fabricated using AM is not a one-size-fits-all process. The material response to stress is highly dependent on the specific conditions of the application. In this work, the material properties of stainless-steel test samples fabricated using LPBF when subjected to rapid loading conditions will be assessed. High velocity gas gun uniaxial strain plate impact experiments were performed to analyze this behavior. Test scope includes examination of build orientation dependence and effects of engineered porosity distributions on wave propagation, damage characteristics, and material response properties in AM materials. Data collection through a combination of in-process velocimetry, microstructure analysis, and post-mortem characterization of soft-recovered samples is used to develop process-structure-property relationships. Focus of this discussion will be on the wave propagation, microstructure, and resulting damage evolution observed in these experiments.
Data Mining the Mesoscale to Study Shock Ignition and Reaction Growth in Pressed Energetic Materials: Judith Brown1; Julia Hartig1; Dan Bolintineanu1; Mitchell Wood1; 1Sandia National Laboratories
The shock to detonation transition (SDT) in many energetic materials is governed by the ignition and growth of chemically reacting hot spots that form due to interaction of the incident shock wave with microstructure features such as internal porosity. Detailed mesoscale simulations of shock propagation in pressed energetic materials are presented to study the effects of morphological features such as pore sizes, spacing, and clustering on hot spot ignition and reaction growth. The features studied range in size from 2-4 pores in various cluster morphologies to ensemble suites of large microstructure domains that encompass many clusters of pores. Full-field predictions of thermodynamic states (temperature, pressure, etc.), reaction progress, and mechanical response (deviatoric stress, plastic strain) for each microstructure are analyzed using high-throughput data mining approaches to discover relationships between microstructure morphology and shock sensitivity across a range of shock pressures.
Dynamic and Spall Behavior of Model Binary Magnesium Alloys Using High-throughput Testing Protocols: Suhas Eswarappa Prameela1; Debjoy Mallick1; Christopher Walker2; Taisuke Sasaki3; Abigail Park1; Elaine Lipkin1; Alice Lee1; Fanuel Mammo1; Christopher DiMarco1; Kazuhiro Hono3; George Pharr2; KT Ramesh1; Timothy Weihs1; 1Johns Hopkins University; 2TAMU; 3NIMS
Magnesium (Mg) alloys hold great promise in building protection materials such as body armor, vehicle armor, and other structures where they undergo high strain rate mechanical loading. Tuning the dynamic and spall performance of Mg alloys can be achieved using alloying and processing to produce different microstructures. These microstructures, if properly designed, can help alter dynamic and/or spall strength. We have processed Mg-Zn alloys under different conditions: solutionized, peak aged and ECAE (equal channel angular extrusion) processed. These alloys have been tested using a high-rate nano-indentation technique and laser-driven micro-spall experiments. These high-throughput, small-volume testing protocols hold great promise in elucidating the role of different microstructures and their impact on the dynamic and spall behavior of Mg alloys.
Microstructural Evolution of Pure Aluminum Revealed by In-situ Synchrotron X-ray Diffraction during Shear Deformation in a High-speed Rotational Diamond Anvil Cell: Tingkun Liu1; Bharat Gwalani1; Joshua Silverstein1; Changyong Park2; Lei Li1; Stas Sinogeikin3; Tamas Varga1; Ayoub Soulami1; Arun Devaraj1; 1Pacific Northwest National Laboratory; 2Argonne National Laboratory; 3DAC Tools, LLC
A newly designed high-speed rotational diamond anvil cell (HSRDAC) was utilized to explore dynamic microstructural evolution of pure aluminum by in-situ synchrotron X-ray diffraction (XRD) under simultaneously applied translational and rotational shear force for simulating the severe shear deformation. A low rotational speed was chosen to initially investigate the performance of HSRDAC and validate the experimentational technique. The XRD results showed significant strain heterogeneity of accumulated plastic shear deformation. The dynamic XRD observation also revealed the microstructural changes compared to static observation. the Ex-situ multimodal characterizations by X-ray computed tomography and advanced electron microscopy were performed to understand the mass transfer and microstructure modification after shear deformation. The results of in-situ studies were correlated with ex-situ multimodal characterizations, which enables a new scientific understanding of the highly dynamic microstructural transformation pathways during severe shear deformation.