SEARCH · Search NASA

Results for “Energy absorber”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2

All sources NASA NTRS DOE OSTI

DOE OSTI2020

Characterizing laser preheat for laser-driven magnetized liner inertial fusion using soft x-ray emission

Laser heating of a gas in a cylindrical liner held in by a thin foil window is a critical process in the MagLIF (magnetized liner inertial fusion) concept. Window burn-through and gas heating for OMEGA scale MagLIF cylinders as a function of time have been determined using spectrally integrated soft x-ray diagnostics. Window laser absorption is classified in terms of the emitted x-rays from the window plasma as a function of laser energy, and shows that laser energy absorbed is weakly dependent on incident intensity. Radiation-hydrodynamic simulations overestimate the amount of laser energy absorbed by the window as evidenced by the increase in x-ray radiation across several photon energy bands compared to experiments. Gas temperatures inferred from soft x-ray emission from the front 1 mm of the liner are shown to evolve in time in a similar manner to simulation predictions. In conclusion, soft x-ray emission from the gas within the region of the liner that is normally imploded is shown to meet the 100 eV requirements set by the initial point design for laser-driven MagLIF.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

DOE OSTI2020

Coulombic friction in metamaterials to dissipate mechanical energy

Product designs from a wide range of industries such as aerospace, automotive, biomedical, and others can benefit from new metamaterials for mechanical energy dissipation. In this study, we explore a novel new class of metamaterials with unit cells that absorb energy via sliding Coulombic friction. Remarkably, even materials such as metals and ceramics, which typically have no intrinsic reversible energy dissipation, can be architected to provide dissipation akin to elastomers. The concept is demonstrated at different scales (centimeter to micrometer), with different materials (metal and polymer), and in different operating environments (high and low temperatures), all showing substantial dissipative improvements over conventional non-contacting lattice unit cells. Further, as with other ‘programmable’ metamaterials, the degree of Coulombic absorption can be tailored for a given application. Additionally, an analytic expression is derived to allow rapid first-order optimization. This new class of Coulombic friction energy absorbers can apply broadly to many industrial sectors such as transportation (e.g. monolithic shock absorbers), biomedical (e.g. prosthetics), athletic equipment (e.g. skis, bicycles, etc.), defense (e.g. vibration tolerant structures), and energy (e.g. survivable electrical grid components).

36 MATERIALS SCIENCE↗

DOE OSTI2024

Impact of Biofouling on Point Absorber Wave Energy Converter Performance and Control

Biofouling is a well-documented problem in naval engineering, but little is known about its effect on wave energy converter (WEC) performance. In this study, the software WEC-Sim is used to simulate the performance of a point absorber WEC that has been biofouled by “hard” species (e.g., mussels, barnacles) to varying degrees. Specifically, biofouling is assumed to change the nonlinear drag forces acting on the WEC, which have quantifiable effects on key performance characteristics such as optimal damping conditions, power, peak displacement, and peak velocity. The results of this analysis are then used to discuss strategies for WEC control as it relates to biofouling. Furthermore, the results show that average power production can decrease by as much as 15% with heavy biofouling and require an adjustment of the optimal control law by up to 20%.

Biofouling↗

DOE OSTI2022

Midfidelity model verification for a point-absorbing wave energy converter with linear power take-off

In the preliminary design stage of a wave energy converter (WEC), researchers need fast and reliable simulation tools. High-fidelity numerical models are usually employed to study the wave-structure interaction, but the computational cost is demanding. As an alternative, midfidelity models can provide simulations in the order of real time. In this study, we operate Uppsala University’s WEC in a relatively mild sea state and model it using WEC-Sim. The model is verified based on OpenFOAM simulations. To analyze the ability of the midfidelity model to capture WEC dynamics, we investigate the system separately with 1, 2, and 3 degrees of freedom. We examine the contribution of viscous phenomena, and study both linear and weakly nonlinear solutions provided by WEC-Sim. Our results indicate that the viscous effects can be neglected in heave and surge motion, but not for pitch. We also find that the weakly nonlinear WEC-Sim solution successfully agrees with the computational fluid dynamics, whereas the linear solution could suggest misleading results.

16 TIDAL AND WAVE POWER↗

DOE OSTI2020

A MEMS dynamic mechanical analyzer for in situ viscoelastic characterization of 3D printed nanostructures

Cellular metamaterial structures with sub-micron features have shown the ability to become excellent energy absorbing materials for impact mitigation due to the enhanced mechanical properties of materials at the nanoscale. However, in order to optimize the design of these energy absorbing metamaterial structures we need to be able to measure the dynamic properties of the sub-micron features such as storage and loss moduli and the loss factor. Therefore, at scale testing is required to capture the scale, temperature, and strain rate dependent material properties of these nanoscale materials. This study presents the design, fabrication, and calibration of a MEMS-based dynamic mechanical analyzer (DMA) that can be directly integrated with the two photon lithography (TPL) process commonly used to fabricate metamaterial structures with nanoscale features. The MEMS-based DMA consists of a chevron style thermal actuator used to generate a tensile load on the structure and two differential capacitive sensors on each side of the structure used to measure load and displacement. This design demonstrated 1.5 ± 0.75 nm displacement resolution and 104 ± 52 nN load resolution, respectively. Dynamic mechanical analysis was successfully conducted on a single nanowire feature printed between the load and displacement stages of the MEMS device with testing frequencies ranging between 0.01–10 Hz and testing temperatures ranging between 22 °C–47 °C. These initial tests on an exemplar TPL part demonstrate that the printed nanowire behaves as a viscoelastic material wherein the transition from glassy to viscous behavior has already set in at the room temperature.

42 ENGINEERING↗

DOE OSTI2021

Midfidelity Model Verification for a Point-Absorbing Wave Energy Converter with Linear Power Take-Off

In the preliminary design stage of a wave energy converter (WEC), fast and reliable simulation tools are required. High-fidelity numerical models are usually employed to study the wave-structure interaction, yet the computational cost is demanding. Instead, mid-fidelity models provide simulations in the order of real time. In this study, Uppsala University WEC operates in a relatively mild sea state and is modeled using WEC-Sim. The model is verified based on OpenFOAM simulations. To analyze the ability of mid-fidelity model to capture the WEC dynamics, the system is investigated separately in 1, 2 and 3 DoF. The contribution of viscous phenomena is examined. Moreover, linear and weakly non-linear solutions provided by WEC-Sim are studied. The results obtained indicate that the viscous effects in heave and surge motion can be neglected but not for the pitch. The weakly non-linear WEC-Sim solution successfully agrees with the CFD, whereas the linear solution could drive to misleading results.

CFD↗

DOE OSTI2021

Midfidelity Model Verification for a Point-Absorbing Wave Energy Converter with Linear Power Takeoff: Preprint

CFD↗

DOE OSTI2022

Systems and methods for additive manufacturing to encapsulate transformative colloidal suspensions

The present disclosure relates to an energy absorbing three dimensional (3D) structure. The structure may have an outer shell formed from a shell material. The outer shell may have a void forming a core volume. A transformative feedstock is contained in the void. The transformative feedstock is encapsulated within the outer shell, within the void, and provides enhanced energy absorbing properties to the 3D structure.

Mancini, Julie A.↗

DOE OSTI2026

Los Alamos National Laboratory R&D Intern

This report details the responsibilities, outcomes, and project details of a summer R&D internship at Los Alamos National Laboratory (LANL). LANL is a multidisciplinary laboratory that focuses on current cutting-edge research in many fields such as national security, engineering, materials science, computational modeling, and advanced manufacturing. The goal of the internship project was to work with lab engineers and resources to develop an energy absorbing structure for high-velocity impact applications. The successful development of this technology and methodology would not only positively impact future project funding but also contribute to the laboratory's commitment to solve national security challenges through simultaneous excellence. Such devices would also support efforts surrounding the research and development of energy absorbing structures and would provide new vital information backed by experimentation. Different computational and modeling methods were used to design these structures, in addition to qualitative background information provided by past literature. The resultant designs were successfully tested, and the test results were successfully quantified. From these results, new computational methods were developed through python programming and modeling to predict ideal materialistic properties for these structures given a sufficiently defined application.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Systems and methods for additive manufacturing to encapsulate transformative colloidal suspensions

The present disclosure relates to a method of forming an energy absorbing three dimensional (3D) structure. The method involves forming an outer shell for the 3D structure from a shell material, the outer shell having a void forming a core volume. The method also involves filling the core volume with a transformative liquid. When the 3D structure is fully formed, the transformative liquid is encapsulated within the outer shell and provides enhanced energy absorbing properties to the 3D structure.

36 MATERIALS SCIENCE↗

DOE OSTI2023

Effect of recycled fibers and shredded intermediates variation on the mechanical properties and energy absorption of fiber‐reinforced composite panels

Abstract The global composite industry generates large quantities of waste which mostly ends up in landfills due to a lack of established end‐use applications for multiple waste streams. The scrap from end‐of‐life (EoL) includes manufacturing waste such as dry chopped fiber tows, loose fibers, shredded fibers from fabric textile operations, cured/semi‐cured prepregs, and fully cured composite structure waste from aircraft, automobiles, wind blades, boats, and pressure vessels. In this work, different composite waste streams were reduced to shredded intermediates, followed by simple blending, and subjected to wet compression molding to produce composite panels. The panels/plaques were tested for mechanical properties (flexure and impact), fiber‐matrix wet‐out, and property bounds. It was found that wet‐compression molding was a viable and scale‐able approach to produce recycled panels from EoL composites shredded scrap. Furthermore, full‐scale size panels for use in truck bodies and intermodal shipping container flooring were manufactured and their impact resistance was tested using a drop weight impact test. They were tested both for high‐ and low‐velocity load. In the case of high‐velocity load, the average impact load was 14,673 N; the average absorbed energy was 101.6 J; the average elastic energy was 11.7 J and the impact resistance was 1065 J/m. In the case of the low‐velocity drop weight impact test, it was found that the average impact load was 7877.358 N; the average absorbed energy was 9.718 J; the average elastic energy was 9.14 J, and the impact resistance was 184.1 J/m. The shredded composite was shown to be a candidate material for the manufacture of truck bodies and intermodal containers’ flooring panels. Highlights By using shredded intermediates from different composite waste streams, it is possible to manufacture composite panels. Wet–compression process is an appropriate technique for manufacturing recycled fiber composite panels. Regardless of the source of scrap, the mechanical properties of the produced composite panels were improved. The recycling process technology can be transformed to commercial scale to produce full‐size transportation flooring panels. A product pathway is established in consideration of lower cost and improved recyclability.

Vaidya, Uday↗

DOE OSTI2026

Adaptive Stiffness Power Take-Off System for a Hydraulic Hose-Pump Point Absorber Wave Energy Converter

Two crucial challenges faced in the design of ocean wave energy converters (WECs) are maintaining high capacity factors and remaining robust in everchanging, harsh ocean environments. This study introduces a novel mechanism for achieving reactive WEC control with a soft hydraulic power take-off, thereby addressing both challenges. The device of interest involves a hydraulic pump, constructed from a fluidic flexible matrix composite (F2MC), which is cyclically stretched by driving waves and pressurizes working fluid through a turbine-generator. This class of fiber-reinforced stretch hoses is established for ocean use as robust moorings and shock absorbers. The dynamic properties of the F2MC pump depend on internal pressure, which can be controlled by a continuously variable transmission between the turbine and generator, allowing the system to be adapted for better performance over a wide range of wave conditions. This work presents a dynamic model for operation and adaptive behavior of this power take-off system, experimentally validates components of the model, and performs dynamic simulations of the system that show increases in power production and capacity factor compared to non-adaptive operation for a variety of driving wave conditions. This work develops the basis for future large-scale experimental testing and controller design of this system.

Wave energy conversion, fluidic flexible matrix co↗

DOE OSTI2025

Machine learning-driven design and self-sensing capabilities of automotive bumper lattices for adaptive impact response

We present a novel approach to design an automotive bumper energy absorber using carbon fiber reinforced polymer composites, optimized to meet conflicting performance requirements for two distinct impact scenarios. The design must satisfy both a low-speed (2.5 mph) pendulum intrusion test, simulating vehicle-to-vehicle collisions, and a high-speed (25 mph) leg flexion test, replicating pedestrian impacts. These tests demand opposing deformation characteristics: high flexibility (deformation < 85 mm) for the former and high stiffness (deformation < 22 mm) for the latter. To address these contradictory requirements, we developed a machine learning (ML) framework for inverse optimization of lattice designs and material selection. Unlike traditional iterative design processes, our ML model directly outputs optimal design parameters and material choices based on target performance inputs. The energy absorber was fabricated using advanced additive manufacturing techniques, including extrusion deposition and digital light processing. The integration of carbon fibers provides multifunctionality to the bumper structure, enabling self-sensing capabilities through changes in electrical resistivity under compression. This electrical response demonstrates high repeatability under multiple cycles at 2% compression and exhibits distinct signatures during crack formation under high deformation. This research offers adaptive performance through innovative design methodologies and smart material integration. The approach has potential applications in various fields requiring adaptive energy absorption and real-time structural health monitoring.

Chawla, Komal [ORNL] (ORCID:0000000190327565)↗

DOE OSTI2021

Reliability-based hull geometry optimisation of a point-absorber wave energy converter with power take-off structural reliability objectives

Recent studies have focused on optimising wave energy converter (WEC) designs, maximising their power performance and techno-economic feasibility. Reliability has yet to be fully considered in these formulations, despite its impact on cost and performance. In this study, this gap is addressed by developing a reliability-based design optimisation framework for WEC hull geometries to explore the trade-off between power performance and power take-off (PTO) system damage equivalent loading (DEL). Optimised hull geometries for two sites are considered (from the centre of the North Sea and off the west coast of Norway), and two directions of motions (heave and surge). Results indicate that site characteristics affect the potential power production and DEL for an optimal WEC design. These are also affected by the direction of motion for power extraction, which also significantly changes optimal hull shape characteristics. Optimal surging WEC designs have edges facing oncoming wave directions, while heaving WECs have pointed bottoms, both to streamline movement. Larger, more convex WECs result in greater power production and DEL, while smaller, more concave WECs result in lesser power production and DEL. These findings underline the importance of considering WEC hull geometry in early design processes to optimise cost, power production, and reliability.

16 TIDAL AND WAVE POWER↗

DOE OSTI2020