Mechanical metamaterials are artificial materials with unique global properties due to the structural geometry and material composition of their unit cell. Typically, mechanical metamaterial cells designed such that, when tessellated, they exhibit as zero or negative Poisson's ratio stiffness. Beyond these applications, can be used achieve tailorable nonlinear deformation responses. Computational methods gradient-based topology optimization (TO) size/shape (SSO) implemented design...

Advances in machine learning algorithms and increased computational efficiencies give engineers new capabilities tools to apply engineering design. Machine models can approximate complex functions and, therefore, be useful for various tasks the design workflow. This paper investigates using reinforcement (RL), a subset of that teaches an agent complete task through accumulating experiences interactive environment, automate designing 2D discretized topologies. RL agents use past learn...

Mechanical metamaterials are regularly implemented in engineering applications due to their unique properties derived from structural geometry and material composition. This study incorporates deep reinforcement learning, a subset of machine learning that teaches an agent complete task through interactive experiences, into mechanical metamaterial design. The approach creates design environment for the iteratively construct with tailorable deformation hysteretic characteristics. Validation...

Interlocking metasurfaces (ILMs) are a new class of mechanical built from architected arrays interlocking features that can serve as nonpermanent, robust joining technology. An ILM's strength is governed by the structural material, orientation, and topology its latching unit cells. The presented work optimized topologies ILM cells to maximize in tensile shear loading using gradient-based parametric optimization genetic algorithms. Experimental validation confirmed designs achieved...

Environmentally assisted cracking (EAC) of aluminum alloys in corrosive atmospheres is an important maintenance and safety issue for U.S. Department Defense assets. EAC initiation propagation cracks influenced by the complex interactions load, environment, alloy properties. Traditional environmental fracture testing conducted under immersion or constant humidity conditions may produce results that are different than measurements collected thin electrolyte layers droplets formed during...

Abstract Although a great deal of success in structural integrity management has been achieved, it may be realized by excessively conservative assumptions, high inspection burdens, and aggressive maintenance repair strategies. Corrosion found to reduce fatigue life, but methods account for modeling are still limited. There is recognized need improve calculations through the inclusion effect existing corrosion damage on fatigue. The feasibility modified analysis process that uses finite...

While using a prosthesis, transtibial amputees can experience pain and discomfort brought on by large pressure gradients at the interface between residual limb prosthetic socket. Current solutions attempt to alleviate these soft homogenous liners reduce distribute pressures. This research investigates an additively manufactured metamaterial inlay with tailored mechanical response peak around limb. The uses hyperelastic behaving (US10244818) comprised of triangular pattern unit cells, 3D...

Abstract While using a prosthesis, transtibial amputees can experience pain and discomfort brought on by large pressure gradients, at the interface between residual limb prosthetic socket. Current solutions attempt to alleviate these gradients soft homogenous liners reduce distribute pressures. This research investigates an additively manufactured metamaterial inlay with adjustable mechanical response in order peak around limb. The uses hyperelastic behaving (US10244818) comprised of...

Mechanical metamaterials are regularly implemented in engineering applications due to their unique properties derived from structural geometry and material composition. This study incorporates deep reinforcement learning, a subset of machine learning that teaches an agent complete task through interactive experiences, into mechanical metamaterial design. The approach creates design environment for the iteratively construct with tailorable deformation hysteretic characteristics. Validation...

Abstract Environment-assisted cracking (EAC) of aluminum alloys in corrosive atmospheres is a significant maintenance and safety issue. EAC influenced by the interaction stress, environment, microstructure. Atmospheric conditions corrosion kinetics are dynamic due to diurnal cycles changing operating conditions. Temperature, relative humidity, surface contaminants interact control thin-film electrolyte properties. Within crack, separation anode cathode may occur concentration gradients...

Advances in machine learning algorithms and increased computational efficiencies give engineers new capabilities tools to apply engineering design. Machine models can approximate complex functions and, therefore, be useful for various tasks the design workflow. This paper investigates using reinforcement (RL), a subset of that teaches an agent complete task through accumulating experiences interactive environment, automate designing 2D discretized topologies. RL agents use past learn...

The shift toward condition-based monitoring is a key area of research for many military, industrial, and commercial customers who want to lower the overall operating costs capital equipment general facilities. Assessing health rotating systems such as gearboxes, bearings, pumps other actuation often rely on need continuous capture transient signals that are evidence events could cause (i.e. cavitation), or be result spalling), damage within system. In some applications this can accomplished...


 Monitoring machine runtime health parameters through nonintrusive means can greatly reduce the up-front time and resource barriers to entry of adding instrumentation existing plant infrastructure. This work presents design evaluation three transducers as part a load monitoring system for rotating machinery. Data collected using custom designed, small-scale induction motor test stand shows dependence large air core RF coil, small coil array, Hall effect sensor outputs on applied speeds...

Abstract A water corrosivity sensing system is currently under development that combines the strengths of rate measurement techniques such as linear polarization resistance with longer-term cumulative damage measurements typically provided by electrical probes. This sensor technology applicable not only to pipeline systems, but a broad range liquid and gas piping systems used in military facilities well electric power, chemical, pulp paper, fossil fuel industries. The corrosion operates on...

Abstract A water corrosivity sensing system is currently under development that has the potential to combine strengths of rate measurement techniques such as linear polarization resistance with longer-term cumulative damage measurements typically provided by electrical probes. This sensor technology applicable not only pipeline systems, but a broad range liquid and gas piping systems used in military facilities well electric power, chemical, pulp paper, fossil fuel industries. The current...