In-situ Nanomechanics of Hierarchical Materials
Abstract
This proposal requests ~$154k to construct an advanced nano-mechanical experimental setup, with simultaneous data collection and obs,ervation capabilities of the deformation of hierarchical composites and advanced, multi-scale and multifunctional materials, with pr,operties ranging from damage tolerance to electrochemical energy storage. This instrument will enhance the quality of PIs DoD-spons,ored research, and the findings generated through the proposed experiments will contribute significantly to the design and fabricati,on of advanced materials through accurate material model formulation and quantification of complex loading schedules. To perform hig,h-accuracy nano-mechanical experiments that can uncover fundamental deformation processes capable of energy absorption, this new ins,trument, FemtoTools in-situ nanoindenter will be inserted into the existing Focused Ion Beam (Versa3D, Thermo Fisher) or into any ot,her electron microscope either in PIs lab (SEM Quanta200 FEG) or in a userfacility (Kavli Nanoscience Institute).Two key focus area,s in PI Greers ONR grant N00014-22-1-2384 are (1) synthesis of advanced materials that are robust against ballistic impact and (2),utilization of computational models to quantify and to eventually predict the deformation and energy absorption in these materials i,n response to impact. Both areas require precise knowledge of material model and constitutive laws. The existing nanomechanical equi,pment suite in PI Greers lab is no longer optimal for obtaining such laws because limitations in travel distance, incompatibility w,ith additional vacuum chambers, monolithic rather than modular design, and unreliable and unresponsive technical customer service su,pport. In addition, material deformation models are developed most precisely when the deformation is conducted under a constant dis,placement rate. Most of the existing nanomechanical instruments are inherently load-controlled, driven by a force actuation mechanis,llow us to:-Conduct monotonic and cyclical compression experiments to gain insight into deformation and failure mechanisms and to as,certain and quantify the energy absorption mechanisms in nano-architec,PIs knowledge, this FemtoTools nanomechanical module is the only instrument capable of intrinsic displacement rate control; all oth,ers are load controlled and provide nominal displacement rate control through a feedback loop. would allow for large stress drops to, be quantified. This pursuit will directly support and enable ONR-funded research (N00014-22-1-2384). -Correlate the morphology of t,he evolving densified region under the indenter tip and mechanical stress vs. strain data acquired at different strain rates, up to,l complexity, including beam- vs. shell-based, periodic vs. aperiodic, junction-based vs. node-less architectures, and material micr,ostructure on the deformation and energy absorption in advanced micro-architected meta-materials and composites. -Analyze these find,ings to gain insight into physical origins and specific roles of hierarchy in design of damage-tolerant, strong, lightweight, and fa,tigue-resistant materials. Extensive research on state-of-the-art nanomechanical equipment market revealed FemtoTools Nanomechanica,l Testing system to be the only instrument that is capable of conducting nanomechanical experiments under displacement rate control,, in addition to being compatible with multiple vacuum chambers for in-situ experiments, having modular design (i.e. additional capab,ilities and easy replacements/repairs), and extending displacement distance and resolution. (Publically Releasable)
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 08, 2022
- Source ID
- N000142212484
Entities
People
- Julia R. Greer
Organizations
- California Institute of Technology
- Office of Naval Research
- United States Navy