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At least 109 records · Page 6

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NASA NTRS2024

Investigation of Carbon-Reinforced Acrylonitrile Butadiene Styrene 3D-Printed Honeycomb Composites

The expansive utility of polymeric 3D printing technologies and demand for high-performance lightweight structures has prompted the emergence of various carbon-reinforced polymer composite filaments. However, detailed characterization of the processing-microstructure-property relationships of these materials is still required to realize their full potential. In this study, acrylonitrile butadiene styrene (ABS) and carbon reinforced ABS variants, both carbon nanotubes (CNT) and 5 wt.% chopped carbon fiber (CF), are fabricated in a honeycomb geometry and investigated across a range of layer thicknesses and hex sizes. Microscopy of material cross-sections is conducted to evaluate the relationship between print parameters and porosity. Additionally, mechanical properties are evaluated through compression testing, demonstrating the potential of honeycomb ABS, ABS-CNT, and ABS-5wt.% CF polymer composites for novel 3D printed structures.

ABS (Acrylonitrile Butadiene Styrene)↗

NASA NTRSDate not supplied

Investigation of Carbon-Reinforced Acrylonitrile Butadiene Styrene 3D-Printed Honeycomb Composites

ABS (Acrylonitrile Butadiene Styrene)↗

DOE OSTI2026

Decorated Honeycomb Lattice and Successive Magnetic Transitions of the Delafossite Derivative K 4 Ni 5 Te 3 O 16

Here, we report the synthesis and characterization of the delafossite derivative K 4 Ni 5 Te 3 O 16 , which hosts a decorated honeycomb Ni 2+ lattice. Single-crystal X-ray diffraction, electron microscopy, and neutron diffraction establish a noncentrosymmetric Pmm2 crystal structure that combines regular honeycomb units with elongated motifs formed by Ni 2+ trimers along extended edges. Magnetic susceptibility reveals strong antiferromagnetic interactions, while heat capacity measurements identify two successive magnetic transitions at 30 and 12 K. Neutron diffraction shows that these transitions correspond to a progression from partial to full long-range magnetic order on distinct Ni sites, reflecting competition among the various exchange interactions. The resulting magnetic point group, mm2.1′, inherits the lattice polarity and permits high-order magnetoelectric coupling. Consistent with this symmetry, a quadratic magnetic-field-induced polarization is experimentally observed below the magnetic ordering temperature, likely arising from exchange-driven magnetostriction coupled to the polar lattice. These results establish K 4 Ni 5 Te 3 O 16 as an interesting platform for engineering B-site ordering in delafossite derivatives to realize complex quantum magnetism and functional responses.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2025

Pressure tuning of competing interactions on a honeycomb lattice

Exchange interactions are mediated via orbital overlaps across chemical bonds. Thus, modifying the bond angles by physical pressure or strain can tune the relative strength of competing interactions. Here we present a remarkable case of such tuning between the Heisenberg (J) and Kitaev (K) exchange, which respectively establish magnetically ordered and spin liquid phases on a honeycomb lattice. We observe a rapid suppression of the Néel temperature (T N ) with pressure in Ag 3 LiRh 2 O 6 , a spin-1/2 honeycomb lattice with both J and K couplings. Using a combined analysis of x-ray data and first-principles calculations, we find that pressure modifies the bond angles in a way that increases the ∣K/J∣ ratio and thereby suppresses T N . Consistent with this picture, we observe a spontaneous onset of muon spin relaxation (μSR) oscillations below T N at low pressure, whereas in the high pressure phase, oscillations appear only when T < T N /2. Unlike other candidate Kitaev materials, Ag 3 LiRh 2 O 6 is tuned toward a quantum critical point by pressure while avoiding a structural dimerization in the relevant pressure range.

36 MATERIALS SCIENCE↗

DOE OSTI2024

Cross-Cap Defects and Fault-Tolerant Logical Gates in the Surface Code and the Honeycomb Floquet Code

We consider the Z 2 toric code, surface code, and Floquet code defined on a nonorientable surface, which can be considered as families of codes extending Shor’s nine-qubit code. We investigate the fault-tolerant logical gates of the Z 2 toric code in this setup, which corresponds to e ↔ m exchanging symmetry of the underlying Z 2 gauge theory. We find that nonorientable geometry provides a new way for the emergent symmetry to act on the code space, and discover the new realization of the fault-tolerant Hadamard gate of the two-dimensional surface code with a single cross cap connecting the vertices nonlocally along a slit, dubbed a nonorientable surface code. This Hadamard gate can be realized by a constant-depth local unitary circuit modulo nonlocality caused by a cross cap. Via folding, the nonorientable surface code can be turned into a bilayer local quantum code, where the folded cross cap is equivalent to a bilayer twist terminated on a gapped boundary and the logical Hadamard only contains local gates with intralayer couplings when being away from the cross cap, as opposed to the interlayer couplings on each site needed in the case of the folded surface code. We further obtain the complete logical Clifford gate set for a stack of nonorientable surface codes and similarly for codes defined on Klein-bottle geometries. We then construct the honeycomb Floquet code in the presence of a single cross cap, and find that the period of the sequential Pauli measurements acts as a H Z logical gate on the single logical qubit, where the cross cap enriches the dynamics compared with the orientable case. We find that the dynamics of the honeycomb Floquet code is precisely described by a condensation operator of the Z 2 gauge theory, and illustrate the exotic dynamics of our code in terms of a condensation operator supported at a nonorientable surface. Published by the American Physical Society 2024

Physics↗

DOE OSTI2025

Dirac Magnon in Honeycomb Lattice Magnet NiTiO 3

We performed inelastic neutron scattering experiments on single-crystal samples of the honeycomb lattice magnet, ilmenite NiTiO 3 . Below the Néel temperature of 22 K, spin wave excitations with a band energy of 3.7 meV were observed. Further, the neutron energy spectra were well-reproduced by modeling the system as a ferromagnetic honeycomb lattice with antiferromagnetic interlayer coupling, using linear spin wave theory. Similar to another ilmenite CoTiO 3 , a crossing structure was observed at the K point, suggesting the presence of Dirac magnons in NiTiO 3 . Further calculations suggested the formation of Dirac nodal line.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

NASA NTRS1967

Nondestructive testing techniques used in analysis of honeycomb structure bond strength

DOT /Driver-Displacement Oriented Transducer/, applicable to both lap shear type application and honeycomb sandwich structures, measures the displacement of the honeycomb composite face sheet. It incorporates an electromagnetic driver and a displacement measuring system into a single unit to provide noncontact bond strength measurements.

Erdman, D. C.↗

NASA NTRS1969

Technique for anchoring fasteners to honeycomb panels

Two-piece fastener bushing provides mounting surface for components on a three-inch thick honeycomb structure. Specially constructed starter drill and sheet metal drill permit drilling without misalignment. Tapered knife-edge cutting tool removes honeycomb core material without tearing the adjacent material.

Brown, W. J.↗

NASA NTRS1974

Adhesive coating eliminated in new honeycomb-core fabrication process

Technique eliminates use of silicone-based adhesive material as bonding medium. Adhesive requires precise time-temperature cure. Prepreg resin is used as bonding medium, and each layer is laminated together to form honeycomb billet. Process can be used in any application where nonmetallic honeycomb core is being fabricated.

Batty, W. L.↗

NASA NTRS1973

Development of Pyrrone structural forms for honeycomb filler

The development of techniques for the preparation of Pyrrone structural foams for use as honeycomb filler is described. The feasibility of preparing foams from polymers formed by the condensation of 3,3'-diaminobenzidine (DAB), or 3,3',4,4'-tetraaminobenzophenone (TABP), with 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA) was investigated. Initially, most of the effort was devoted to preparing Pyrrone prepolymers with improved and more reproducible foaming properties for making chemically blown foams. When it became apparent that very high curing shrinkages would not allow the use of unfilled Pyrrone prepolymers in a foam-in-place process, emphasis was shifted from chemically blown foams to syntactic foams. Syntactic foam formulations containing hollow carbon microspheres were developed. Syntactic foams made from selected formulations were found to have very low coefficients of thermal expansion. A technique was developed for the emplacement of Pyrrone syntactic foam formulations in honeycomb core structures.

Kimmel, B. G.↗

NASA NTRS1977

Honeycomb chassis for electronic components

In new electronic chassis support, machined honeycomb members are used to change basic relationship between chassis and support structure. Improved chassis combines internal and external support and heat dissipation by altering chassis internal geometry. Honeycomb materials allow mechanical support and thermal load sharing to be combined at lower weight and lower cost than previous equipment.

Read, W. S.↗

NASA NTRS1977

Extruded edge members for honeycombs

Edge members in bonded honeycomb panel structures are conventionally made by machining channels in aluminum bars. Open ends are stuffed with honeycomb core, using intumescent adhesive. Less expensive technique eliminates need for stuffing. Extended edges are more reliable, lighter, and easier to install. New manufacturing method may prove useful in fabricating structures such as air-frames, recreational-vehicle frame members, and the like in which weight savings is primary goal.

Haskell, D. R.↗

NASA NTRS1979

Detecting moisture in composite honeycomb panels

Radiographic inspection technique detects liquids trapped in cells of honeycomb composite panels constructed with porous fiber-reinforced plastic skins. Procedure is of use in industries such as aerospace or automotive engineering where honeycomb composites are being used or studied.

Culp, J. D.↗

NASA NTRS1979

Glass polyimide honeycomb cores for advanced space transportation systems

The use of a glass fiber reinforced polyimide honeycomb was considered for various applications requiring lightweight stiff structures which may experience temperatures up to 600K. The experiences and results of fabricating these core types are reported. The process parameters and most desirable characteristics are noted. The differences in considering resins for making laminates versus their use in surface coatings are stressed. This comparison is made to explain the problems encountered in using the three new resin types for dipping honeycomb to the desired density. Some properties and the effect of post cure, forming and ventilating techniques for the condensation polyimide core types are presented.

Brentjes, J.↗

NASA NTRS1980

Comparison of structural behavior of superplastically formed/diffusion-bonded sandwich structures and honeycomb core sandwich structures

A superplasticity formed/diffusion-bonded (SPF/DB) orthogonally corrugated core sandwich structure is discussed and its structural behavior is compared to that of a conventional honeycomb core sandwich structure. The stiffness and buckling characteristics of the two types of sandwich structures are compared under conditions of equal structural density. It is shown that under certain conditions, the SPF/DB orthogonally corrugated core sandwich structure is slightly more efficient than the optimum honeycomb core (square-cell core) sandwich structure. However, under different conditions, this effect can be reversed.

Ko, W. L.↗

NASA NTRS1979

The structural behavior of a graphite-polymide honeycomb sandwich panel with quasi-isotropic face sheets and an orthotropic core

The results of a series of tests of graphite-polyimide honeycomb sandwich panels are presented. The panels were 1.22 m long, 0.508 m wide, and approximately 13.3 m thick. The face sheets were a T-300/PMR-15 fabric in a quasi-isotropic layup and were 0.279 mm thick. The core was Hexcel HRH 327-3/16 - 4.0 glass reinforced polyimide honeycomb, 12.7 mm thick. Three panels were used in the test: one was cut into smaller pieces for testing as beam, compression, and shear specimens; a second panel was used for plate bending tests; the third panel was used for in-plane stability tests. Presented are the experimental results of four point bending tests, short block compression tests, core transverse shear modulus, three point bending tests, vibration tests, plate bending tests, and panel stability tests. The results of the first three tests are used to predict the results of some of the other tests. The predictions and experimental results are compared, and the agreement is quite good.

Hyer, M. W.↗

NASA NTRS1981

Parametric results for heat transfer across honeycomb sandwich panels

The problem of heat transfer across honeycomb sandwich panels is theoretically investigated. The basic objective is to predict the rear surface temperature as a function of time when the front surface is exposed to a prescribed heat flux; the faces are bounded by planar sheets so that the air circulation in the honeycomb cells is bounded and contained. The influence of the air circulation on convective heat transfer is explicitly included. Drawing upon previous investigators' results that indicated various relations for the Nusselt numbers vs Rayleigh numbers in different regimes of the aspect ratio (defined as the ratio of the cell height to cell width), parametric calculations are performed to predict the rear surface temperatures. Chemical degradation of the material, especially the glue holding the face material on the end, is important but has not yet been included. The results indicate that decreasing the cell width, increasing the cell wall thickness and increasing the cell height all have beneficial effects upon the heat transfer; i.e., all of these variations reduce rear surface temperature for a given time for a prescribed heat flux on the front surface.

Ramohalli, K.↗

NASA NTRS1982

Development of Rene' 41 honeycomb structure as an integral cryogenic tankage/fuselage concept for future space transportation systems

The status of the structural development of an integral cryogenic-tankage/hot-fuselage concept for future space transportation systems (STS) is discussed. The concept consists of a honeycomb sandwich structure which serves the combined functions of containment of cryogenic fuel, support of vehicle loads, and thermal protection from an entry heating environment. The inner face sheet is exposed to a cryogenic (LH2) temperature of -423 F during boost; and the outer face sheet, which is slotted to reduce thermal stress, is exposed to a maximum temperature of 1400 F during a high altitude, gliding entry. A fabrication process for a Rene' 41 honeycomb sandwich panel with a core density less than 1 percent was developed which is consistent with desirable heat treatment processes for high strength.

Shideler, J. J.↗