Fabrication Of Specimens Research Articles

Mechanical Properties of the Stereolithography Resin with Different Printing Configurations.

In the 3D printer market, there are several types of printing; among those found in the middle are fused filament deposition printing and stereolithography. In stereolithography, layers of resin are solidified employing UV rays. Each manufacturer offers different types of resins that react to light exposure. These usually have very general values in terms of their mechanical strength, with varying properties depending on the printing configurations. For this reason, the user, in many cases, must make trial and error prints to obtain the best possible printing configuration, generating expenses and waste of material. This research proposes establishing the appropriate printing parameters to obtain the best mechanical properties of the prototypes printed in the digital light process stereolithography printer of the Universidad Tecnica del Norte. A specimen fabrication process based on the ASTM D638 standard is established, in which the main printing configurations are varied, such as printing orientation, layer thickness, and light exposure time. Experimental tensile tests obtain deformation stress-strain curves. From this, the behavior of the printed material is obtained as linear elastic-fragile. The results obtained are compared concerning the maximum stress and strain, and the modulus of elasticity is calculated. The most suitable printing parameters are proposed to obtain the best results in stereolithography printing for the construction of functional prototypes.

Mechanical and Biocompatibility Properties of Sintered Titanium Powder for Mimetic 3D-Printed Bone Scaffolds.

A composite comprising Ti and NaCl powders was sintered similar to a three-dimensional (3D)-printed patient-customized artificial bone scaffold. Additionally, a proper microstructure of the mimetic scaffold and the optimum processing parameters for its development were analyzed. The mechanical properties of the metal-based porous-structured framework used as an artificial bone scaffold were an optimum replacement for the human bone. Thus, it was confirmed that patient-customized scaffolds could be manufactured via 3D printing. The 3D-printed mimetic specimens were fabricated by a powder-sintering method using Ti for the metal parts, NaCl as the pore former, and polylactic acid as the biodegradable binder. Scanning electron microscopy (SEM) images showed that pores were formed homogeneously, while X-ray computed tomography confirmed that open pores were generated. The porosity and pore size distribution were measured using a mercury porosimeter, while the flexural strength and flexural elastic modulus were calculated using the three-point bending test. Based on these measurements, a pore-former content of 15 vol % optimized the density and flexural strength to 2.52 g cm–2 and 283 MPa, respectively, similar to those of the actual iliac bone. According to the 3D-printing production method, a selective laser-sintering process was applied for the fabrication of the mimetic specimen, and it was determined that the microstructure and properties similar to those of previous metal specimens could be achieved in the as-prepared specimen. Additionally, a decellularized extracellular matrix (dECM) was used to coat the surfaces and interiors of the specimens for evaluating their biocompatibilities. SEM image analysis indicated that the adipose-derived stem cells grew evenly inside the pores of the coated specimens, as compared with the bulky Ti specimens without the dECM coating. The doubling time at 65% was measured at 72, 75, and 83 h for specimens with pore-former contents of 5, 10, and 15 vol %, respectively. The doubling time without the pore former was 116 h. As compared with the specimens without the pore former (73 h), 15% of the dECM-coated specimens showed a doubling time of 64%, measured at 47 h.

Multimaterial Extrusion‐Based Additive Manufacturing of Compliant Crack Arrester: Influence of Interlayer Length, Thickness, and Applied Strain Rate

Additive manufacturing is a useful tool for fabricating complex multimaterial structures. Compliant interlayers (ILs) can easily be introduced into stiff materials to increase toughness and stop or impede crack growth, as is done in nature. The aim herein is to analyze the influence of varying IL lengths and thicknesses on crack propagation in 3D‐printed polymers at different loading rates. A glycol‐modified poly(ethylene terephthalate) is used as a matrix material, while a thermoplastic elastomer on a copolyester basis serves as an compliant IL. Specimen fabrication is done with a fused filament fabrication 3D printer equipped with a multimaterial unit, which allows to print a component composed of several materials within one print. Additively manufactured Charpy samples are tested in three‐point bending at loading rates between 0.1 mm min−1and 3.8 m s−1. The thickness of the IL almost shows no effect on energy absorption as long as remaining in the same printing orientation and loading rate. For varying IL lengths, a constant fight between crack penetration and crack deflection occurs. At low loading rates, the IL acts as a defect. As the loading rate increases, the total absorbed energy of composites increases compared with the pure matrix material.

Mechanical response of polyacrylamide breast tissue phantoms: Formulation, characterization and modeling

In the context of breast cancer detection, mechanical imaging is an emerging technique for screening breast cancer. In view of its promise, it deserves a detailed investigation. Development of material that can emulate tissue behavior is essential for research. This work is concerned with the fabrication of polymeric specimens to capture the mechanical behavior of human breast tissues. Three types of tissue phantoms are fabricated: fat, glandular and ductal carcinoma tissues. The fabricated phantoms are compared to available human breast tissue data obtained through compression tests and stress relaxation tests. Further, the fabricated tissue phantoms are subjected to stress relaxation tests to characterize their viscoelastic response. A finite strain viscoelastic constitute model is proposed to describe the mechanical response of the breast tissue phantoms. The model is calibrated using experimental data for phantom tissue specimens. Both phantom tissue specimens and model predictions show reasonable trends. The phantom tissues and model may be of utility in developing mechanical imaging setups.

An additively-manufactured molten salt-to-supercritical carbon di-oxide primary heat exchanger for solar thermal power generation – Design and techno-economic performance

The design and techno-economic performance of a compact additively manufactured (AM) molten salt (MS)-to-supercritical carbon di-oxide (sCO2) primary heat exchanger (PHE) for solar thermal application is described. The PHE design consists of sCO2 flow through an array of microscale pin fins while the MS flows through mm-scale rectangular channels. Constraints imposed by AM using laser powder bed fusion method are considered in the design. Structural and fluid flow simulations are performed to arrive at a viable design of the core and headers. A simplified one-dimensional steady state model for the PHE is developed including the impact of surface roughness from the AM process. A process-based cost model is used to determine the tradeoff between thermofluidic design and manufacturing cost.A parametric study is performed using the thermo-fluidic and cost models to determine the set of geometrical and flow variables that result in high power density and low cost, while restricting the pressure drop on the sCO2 side to less than 2% of line pressure. Flow rates of MS and sCO2 were varied over heat capacity rate ratios ranging from 0.2 to 1. Results indicate that it is possible to design a low-pressure drop AM PHE with an effectiveness of 90% and a power density in excess of 10 MW/m3 (including headers). Fabrication of representative nickel superalloy specimens are shown to demonstrate that low-porosity parts with the requisite dimensional tolerance of PHE core can be generated.

A method to evaluate the tensile strength and ductility of asphalt binders using a thin confined film

ABSTRACT It has become clear over the last few years with an increasing use of asphalt binder modifiers, additives and recycled materials that there is a need to develop methods and concomitant parameters that can evaluate the full tensile behaviour including nonlinearity and damage resistance of asphalt binders. This study presents a simple, repeatable test method to examine the tensile strength and ductility of asphalt binders using a poker-chip geometry. The poker-chip geometry has previously been used to induce a realistic stress state in asphalt binder similar to that exerted on asphalt binder confined between two aggregates. This study develops and presents a new simplified procedure for specimen fabrication and preparation using the poker-chip geometry. A set of nearly 100 asphalt binders including different aging conditions, different levels and types of modification, and recycled asphalt binders and contents were examined using the proposed approach. The results indicate that a ductility parameter obtained using the test is highly repeatable with an average coefficient of variation of 9%. In addition, the test was able to distinguish between different levels of modification and was sensitive to aging, recycled binder ratio and modifier type.v

Investigation on the flexural properties of sandwich beams with auxetic core

Availing cellular structures as the core of sandwich beams is an innovative approach to improve the efficiency of them. Nonetheless, the flexural characteristics of sandwich beams are affiliated to the core topology. Accordingly, choosing an appropriate core can have a significant efficacy on the performance of sandwich beams. The purpose of the present study is to assess the influence of using auxetic cores in flexural properties of sandwich beams. Specifically, experimental and finite element approaches were implemented to evaluate the flexural behavior, energy absorption and the stiffness of fully integrated 3D printed polymeric sandwich beams, made of square node anti-tetra chiral, arrowhead and re-entrant auxetic cores, compared with the conventional honeycomb core. Fabrication of specimens was performed using the FDM 3D printing method, and three-point bending tests were conducted on the printed specimens. Results indicated that selection of proper core topology has remarkable effect on the flexural properties of sandwich beams, and using auxetic core is potentially an efficient method to enhance mechanical properties of sandwich beams due to high load bearing capacity.

Optimization and characterization of surface treated Lagenaria siceraria fiber and its reinforcement effect on epoxy composites

PurposeThis paper aims to investigate the resultant optimal ultimate tensile strength, elongation, flexural strength and modulus, compression strength and impact strength of fabricated alkali-treated Lagenaria siceraria fiber (LSF)-reinforced polymer matrix composite by optimizing input factors and microstructural characterization by influencing fiber length, fiber concentration and treatment condition of LSF.Design/methodology/approachThe fabrication of LSF-reinforced composite specimens involved surface treatment followed by custom experimental design using a simple hand layup process. The wear analysis was performed by a multi-tribotester TR25 machine, and the developed model was validated by using statistical software Design Expert V.8 and analysis of variance (ANOVA). The surface morphology of the sample was also analyzed by field emission scanning electron microscopy.FindingsThe alkali treatment for LSFs had reduced the hemicellulose, and enhanced mechanical performance was observed for 30 wt.% concentration of L. siceraria in epoxy resin. Thermogravimetric analysis revealed thermal stability up to 245°C; microstructure revealed fiber entanglements in case of longer fiber length and compression strength reduction; and the surface-treated fiber composites exhibited reduced occurrences of defects and enhanced matrix–fiber bonding. Enhanced mechanical performances were observed, namely, ultimate tensile strength of 17.072 MPa, elongation of 1.847%, flexural strength of 50.4 MPa, flexural modulus of 3,376.31 GPa, compression strength of 52.154 MPa and impact strength of 0.53 joules.Originality/valueThe novel approach of optimizing and characterizing alkali surface-treated LSF-reinforced epoxy matrix composite was explored, varying fiber length and concentrations for specimens by empirical relations and experimental design to obtain optimal performance validated by ANOVA. Enhanced properties were obtained for: 7 mm fiber length and 30 wt.% concentration of fiber in the composite for alkali-treated fiber.

High-pressure compacted recycled polymeric composite waste materials for marine applications

Options for recycling fiber composite polymer (FCP) materials are scarce, as these materials cannot be normally recycled and are toxic when improperly disposed. Additionally, reducing water usage is an increasing concern, as the concrete industry currently uses 10% of the world’s industrial water. Therefore, building upon our previous work, this research explores the use of polymer hybrid carbon and glass composite waste products as reinforcements in high-pressure compacted cement. Our material used nearly 70% less water during manufacturing and exhibited improved durability and salt corrosion resistance. Compression strength tests were performed on high-pressure compacted materials containing 6.0 wt% recycled admixtures before and after saltwater aging, and the results showed that the material retained 90% of its original compression strength after aging, as it contained fewer pores and cavities. Our experimental work was supplemented by molecular dynamics. Simulations, which indicated that the synergetic effects of compaction and FCP admixture addition slowed the diffusion of corrosive salt ions by an average of 84%. Thus, our high-pressure compacted cement material may be suitable for extended use in marine environments, while also reducing the amount of commercial fiber composite polymer waste material that is sent to the landfill.Article HighlightsFiber composite waste was successfully recycled into denser, high-pressure compacted ordinary Portland cement materials.High-pressure compacted cement samples containing 6% recycled admixtures retained 90% of their compression strength after salt aging.The high-pressure compaction method utilized 70% less water during specimen fabrication.

An insight into the effect of printing orientation on tensile strength of multi-infill pattern 3D printed specimen: Experimental study

This research aims to investigate printing orientation effect on tensile properties of Multi-Infill Pattern (MIP) specimens fabricated by Fused Deposition Modelling (FDM). The material selected for fabrication of specimen is Poly-lactic Acid (PLA), and the thermal stability of PLA material was examined using Thermal Gravimetric Analysis (TGA). The print orientation selected in this study were flat and on-edge orientation. The up-right orientation was not considered because, in this orientation, the parts are built along the z-axis, which results in minimum strength. The MIP consists of honeycomb, triangular and rectilinear patterns fabricated with 25%, 50%, 75% and 100% infill density. The tensile specimen has been designed as per the ASTM D638 standard. The result represents that the printing orientation has influenced the tensile strength of MIP specimen. Higher tensile strength and tensile strength/mass ratio are observed in the on-edge orientation of MIP specimen. The specimen in on-edge orientation with 100% infill density has resulted in higher tensile strength of 30.91 MPa and tensile strength/mass ratio of 3.87 MPa/g. Based on the literature study, the tensile strength of rectilinear, honeycomb and triangular infill pattern PLA specimen with 80% infill density was 10.48 MPa, 10.72 MPa and 20.39 MPa respectively. Hence it can be concluded that the specimen with a MIP has more tensile strength compared to a single infill pattern specimen. Also, trans-layer failure was observed in MIP specimens printed in both orientations.

Glass and metallurgical wastes in facing ceramics production

Purpose: The aim of this work is facing ceramic brick production using glass and metallurgical wastes. Methodology: Compressive strength, density, water absorption testing. Findings: The facing ceramic specimens are obtained at a 1050 °C baking temperature by using a mixture consisting of 40 % clay and 60 % broken glass. The operating modes for the laboratory specimen fabrication are selected such that they possess 2064 kg/m3 density and 42.24 MPa compressive strength. The specimens are characterized by the formation of close pores.

Dependence of mechanical properties and microstructure on solidification onset temperature for Al2024–CaB6 alloys processed using laser powder bed fusion

The addition of a sufficient amount of the potent heterogeneous nucleating agent CaB6 enables the fabrication of crack-free specimens from the solidification-crack susceptible high-strength 2024 (Al–Cu–Mg) aluminum (Al) alloy using laser powder bed fusion (LPBF). The present work investigates the effects of varying addition contents of CaB6 nanoparticles (0.0–2.0 wt%) on the alloys' solidification behavior as well as the specimens’ solidification-crack volume, microstructure, and mechanical properties.The findings of X-ray microscopy (XRM) analyses on LPBF specimens and in-situ differential fast scanning calorimetry (DFSC) analyses on single powder particles at LPBF-like high heating and cooling rates reveal decreasing crack volumes with decreasing solidification supercooling. A CaB6 content of equal to or greater than 0.5 wt% effectively suppresses solidification cracking. 1.0 wt% is defined as the optimum CaB6 content in terms of mechanical properties. With this content an average grain size of 0.77 μm, an ultimate tensile strength (UTS) of 478 ± 4 MPa and an elongation (A) of 13.2 ± 0.1% are achieved. When the CaB6 content is further increased, the alloy's average grain size asymptotically approaches a minimum size of ∼0.7 μm for the given process parameters. This value corresponds to the nucleation-free zone (NFZ), within which the CaB6 nanoparticles present are not activated as nucleating agents, resulting in deposition along the grain boundaries.

RILEM Standard: testing methods for determination of the double-K criterion for crack propagation in concrete using wedge-splitting tests and three-point bending beam tests, recommendation of RILEM TC265-TDK

In this recommendation, standard testing methods for determination of the double-K criterion for Mode I crack propagation in concrete using wedge-splitting tests and three-point bending beam tests are specified for the fracture parameters of the initial cracking toughness K_{Ic}^{ini} and the unstable fracture toughness K_{Ic}^{un}. Along with the recommendation of the standard testing methods, the theoretical background of the double-K criterion, the calculation methods and the results of round-robin testing for determining the double-K fracture parameters are presented in technical reports [1, 2]. The recommendation of the standard testing methods includes geometry for specimens, fabrication of specimens, testing machine, load transmission system and supports, measuring instruments, determination of initial cracking load Pini, determination of measured maximum load Pmax and initial compliance ci, calculation methods for wedge-splitting test and three-point bending beam test, as well as the testing results and testing report forms. According to these methods, the measured fracture parameters of double-K criterion can be used to describe the onset of cracking, and the onset of unstable cracking or failure for predicting crack initiation, structure failure and crack stability in concrete structures.

Characterization of femtosecond laser micromachined specimens extracted from PBF-LB/M microstruts: Analyzing surfaces fabricated via internally linked machined kerfs

The as-built surface morphology on micro-scale parts produced by laser powder bed fusion (PBF-LB/M) considerably influences their mechanical behavior. Femtosecond pulsed laser was utilized to selectively ablate surface regions of stainless steel microstruts produced by PBF-LB/M, allowing the fabrication of micro-scale specimens for tensile and surface characterization of its intrinsic or "roughness-free" mechanical behavior. The study fabricates 280μmx400μm cross-sectioned specimens from vertically built PBF-LB/M microstruts of 500μm nominal diameter. The new micromachining strategy utilized in this work was designed to ensure similar roughness at the edges and faces of the specimens, the average Ra are 1.2±0.4μm and 0.9±0.2μm, respectively, as well as to impart low curvature at edges, i.e. ρ=3±1μm. In addition, the micromachined surfaces revealed an increased average hardness from 276±11HV to 340±14HV at near-surface depths <3.6μm and similar bidirectional compressive residual stresses in laser incidence and scan directions, i.e. −371±65MPa and −429±41MPa, respectively. The effect of surface morphology and hardened surface layer on tensile elongation are negligible, as the average yield strength, ultimate tensile strength, and uniform tensile strain obtained for the micromachined specimens are comparable to those obtained from electropolished counterparts.

Laser free-form fabrication of dual phase DP600 steel using water atomized feedstock powder

Wrought dual-phase (DP) steels are exploited extensively within the automotive sector in the manufacture of components critical to occupant safety. Despite the widespread deployment of these alloys in wrought form, there exists an acute lack of knowledge on their performance/applicability in the context of additive manufacturing (AM). To address this knowledge gap, a preliminary study into the feasibility of utilizing laser directed energy deposition as a means to fabricate prototype structural components from a water atomized dual-phase (DP600) steel powder was completed. A statistical design of experiments approach was used to parametrically model the effects of laser power, traverse rate, hatch spacing, z-step size and powder feed rate on the density, tensile properties, microstructure, and impurity content (O-H-N) of the deposited products produced from each powder. Using optimized parameters, specimen with densities of up to 7.867 g/cm 3 (were obtained while maintaining an equiaxed ferritic microstructure. Intercritical heat treatment developed the requisite dual phase microstructure and elevated tensile properties to effectively match wrought DP600. The prototyping capability of this material and system were then demonstrated through the fabrication of large format tubular specimen coupled with quasi-static axial compression tests.

Demonstration of a High-Throughput Tensile Testing Technique Using Femtosecond Laser-Fabricated Tensile Bars in AISI 316 and Additively Manufactured Grade 91 Steel

Femtosecond laser machining offers a fast, low damage route to fabricating features on the order of a few micrometers to millimeters. Within this broad application space, mechanical testing samples on this scale provides a combination of region selectivity and a bulk-like response. Use of such mechanical test specimens, however, is relatively unexplored compared to microscale and macroscale testing. The present study showcases the benefit of combining efficient specimen fabrication and testing on the mesoscale for extracting a more comprehensive picture of material mechanical properties. Moreover, a material with a complex and heterogeneous microstructure, additively manufactured grade 91, has also been studied to highlight the considerations needed and limitations of testing on this scale.

Beneficial Effects of Cerium Addition to Sulfide Inclusions on Pitting Corrosion Resistance of Stainless Steels

The pit initiation sites for commercial stainless steels have been attributed to sulfide inclusions such as MnS. The chemical composition of the inclusions affects the pitting corrosion resistance of stainless steels. It is known that the inclusion solubility in aqueous solutions affects pitting corrosion resistance. The dissolution of sulfide inclusions produces S species and exposes the bare surface of the steel matrix, resulting in high pitting susceptibility near the inclusions.1 Cerium is expected to be an additive element for insolubilizing water-soluble inclusions because Ce tends to form sulfides and Ce-sulfides exhibit low solubility in aqueous solutions. Additionally, Ce ions have been shown to be effective in the corrosion inhibition of stainless steel. In this study, a microelectrochemical technique was applied to analyze the effect of Ce addition to sulfide inclusions on the pitting corrosion resistance of stainless steels.2,3 To analyze the effect of Ce addition on water solubility of CaS inclusions, spark plasma sintering was used in the facile fabrication of stainless steel specimens containing artificial Ce-added and Ce-free inclusions.3,4,5 The pit initiation resistance at the Ce-added CaS inclusions was higher than that at the Ce-free CaS inclusions. The surface of the Ce-free CaS inclusions largely dissolved during immersion in 0.1 M NaCl, while a large part of the Ce-added CaS inclusions remained undissolved. Thermodynamic calculation showed that CeS is less soluble than CaS.To analyze the effect of Ce ions on pitting at sulfide inclusions, a type 304 stainless steel (Fe-18Cr-8Ni-1.5Mn-0.02S) was prepared by vacuum induction melting. Manganese sulfide inclusions existed in the specimens. Polarization curves were measured in 3 M NaCl and 2.97 M NaCl-0.01 M CeCl3. Pitting occurred at the MnS inclusions in the Ce3+-free solution, whereas no stable pit was generated in the Ce3+-containing solution even when metastable pitting events were observed.It was found that Ce addition inhibits the dissolution of water-soluble inclusions and improved pitting corrosion resistance. Moreover, the Ce3+ ions are expected to inhibit the pitting even after the dissolution of Ce-added inclusions.

Influence of layering sequences on tensile properties of hybrid woven Jute/Ramie fibre reinforced polyester composites

Many researchers around the globe have shifted their focus onto the renewable resources lately. This trend is due to the number of resources that are almost reaching its critical stage hence the exploration of natural fibre composites has also caught the world’s attention. In this research the effect of the number of layers, stacking sequences, and orientation of plain weave jute and ramie fibre single/hybrid composites on tensile properties were investigated. The stacking sequences consisted of two and three layered of laminated composite of pure jute (JJ, JJJ), pure ramie (RR, RRR) and ramie/ramie/ramie (RRR), whereas jute/ramie (JR), jute/jute/ramie (JJR), jute/ramie/jute (JRJ), ramie/jute/ramie (RJR), jute/ramie/ramie (JRR) were included under the hybrid composites category. The comparisons of tensile properties for each of the pure polyester, single, and hybrid composites were evaluated afterwards. The tensile strength and tensile modulus of the composites that was constructed with different fibre direction of warp and weft for each layer were also analyzed. The hand lay-up method was employed for all the fabrication of the composite specimens. From the results, it was observed that the tensile properties of the skin-core type composites (RJR, JRJ) have showed a better performance compared to the skin-eccentric types (RRJ, JJR) with similar ramie content. Attributed to a good fibre rigidity of Ramie fibre, the tensile strength and tensile modulus values could be enhanced with the addition of the ramie content in the composite mixture. The tensile properties were proven to also be improved with the increase number of woven layers in the composite. The Jute/ramie hybrid composite has exhibited very high potential in the future development of the automotive industry.

Influence of slicing parameters on selected mechanical properties of fused deposition modeling prints

This research work highlights the influence of fused deposition modeling (FDM) process parameters on the selected mechanical properties such as young’s modulus and surface roughness of FDM prints have been studied by using Taguchi designed L9 orthogonal array (OA) design of experiments (DOEs). Polylactic acid (PLA) feedstock filament has been used for the fabrication of specimens (as per ASTM D638 standard). The critical input parameters selected were namely layer thickness, raster angle and infill pattern. The strength at peak varies in the range of 26 to 38.91 (MPa), whereas strength at break lies in the range of 23.4 to 35.02 (MPa). Elongation at peak lies in the range of 5%-6%. Surface roughness along X axis lies in the range of 3.18 µm to 9.21 µm, whereas along Y axis, it remains in the range of 3.133 µm to 9.512 µm. The average value lies in the range of 4.44 µm to 7.18 µm. The results show that the specimen prepared with the combination of layer thickness 0.16 mm, raster angle 60° and cubic infill pattern has very good mechanical properties.

Single carbon fiber transverse electrical resistivity measurement via the van der Pauw method

Although the electrical properties of carbon fibers and carbon fiber composites are critical to the design of composite materials, a direct measurement of the transverse electrical resistivity of a single carbon fiber has not yet been reported. Significant challenges arise in fabricating specimens and making electrical resistance measurements due to the geometry and small diameter of a single carbon fiber (about 4–7 μm). In this study, we report a specimen design and fabrication technique for measuring the transverse electrical resistance of an individual carbon fiber by the van der Pauw method. IM7 carbon fiber specimens are fabricated by a combination of photolithography and the focused ion beam. Specimen thickness, which is required for resistivity calculations, is measured by atomic force microscopy. We measure mean transverse electrical resistivity of (9.3 ± 0.3) × 10−5 Ω m, which is roughly six times greater than the reported longitudinal values. Our measurement technique can be applied to a range of conductive fibers. More accurate measurements of the electrical conduction in carbon fibers are critical for applications such as electromagnetic interference shielding, structural health monitoring, and lightning strike protection.