Frictional anisotropy in casted seismic faults: or how to 3D print a fault to better characterize it

Author(s):  
Alain Steyer ◽  
Tom Vincent-Dospital ◽  
Renaud Toussaint

<p>Anisotropic phenomena have long been studied in the vicinity of seismic faults. It has for instance been shown that both in situ pore fluids and seismic mechanical waves travel at different velocities along various directions of a fault zone. Yet, while more and more complexity and disorder in seismic models are introduced to better understand earthquakes, frictional anisotropy is only rarely regarded. In many other domains than geophysics, however, such anisotropy in solid friction is believed to be crucial. For instance, the tribology of rubber tires, skis or advanced adhesives is improved when those are designed to have a preferential frictional direction. But numerous natural systems also benefit from such anisotropy: is is notably essential in the motion of numerous animal skins and in the efficient hydration of some plants. In most cases, these frictional anisotropies derive from the existence of preferential topographic orientations on, at least, one of the contact surfaces, with scales for such structural directivity that can be multiple and various. Seismic faults also exhibit such preferential directions in their topography: unique rock crystals, such as antigorite, can already display some frictional anisotropy, fault zones are  initiated by early fractures that often propagates through layered sediments, generating ramp-flat morphology in their surfaces and, finally, mature faults are marked by grooves of various wavelengths due to the slip induced erosion.</p><p> </p><p>In this work, we study how the morphology of faults affects their stability, as understood by their Coulomb static coefficient of friction. In particular we study its anisotropy with the slip direction. To do so, we make use of the 3D-printing technology and print actual fault surfaces, that were measured in the field. We perform friction experiments with gypsum casts of these 3D-printed faults, as mineral-like materials might deform differently under shear than plastic materials. With these experiments, we show that the friction coefficient along seismic faults is highly anisotropic, with slip motions that are easier in, but not limited to, the direction of the main grooves. This anisotropy could for instance be paramount to better predict the next direction of rupture along some faults under a varying stress state. In some cases, it could indeed not only be related to the orientation of the main regional stress, but also to the structural anisotropy, and  depending on stress and friction anisotropy, along which orientation a rupture criterion will first be exceeded.</p>

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2518
Author(s):  
Nunzio Cennamo ◽  
Lorena Saitta ◽  
Claudio Tosto ◽  
Francesco Arcadio ◽  
Luigi Zeni ◽  
...  

In this work, a novel approach to realize a plasmonic sensor is presented. The proposed optical sensor device is designed, manufactured, and experimentally tested. Two photo-curable resins are used to 3D print a surface plasmon resonance (SPR) sensor. Both numerical and experimental analyses are presented in the paper. The numerical and experimental results confirm that the 3D printed SPR sensor presents performances, in term of figure of merit (FOM), very similar to other SPR sensors made using plastic optical fibers (POFs). For the 3D printed sensor, the measured FOM is 13.6 versus 13.4 for the SPR-POF configuration. The cost analysis shows that the 3D printed SPR sensor can be manufactured at low cost (∼15 €) that is competitive with traditional sensors. The approach presented here allows to realize an innovative SPR sensor showing low-cost, 3D-printing manufacturing free design and the feasibility to be integrated with other optical devices on the same plastic planar support, thus opening undisclosed future for the optical sensor systems.


TEM Journal ◽  
2020 ◽  
pp. 966-970
Author(s):  
Damir Hodžić ◽  
Adi Pandžić ◽  
Ismar Hajro ◽  
Petar Tasić

Widely used additive manufacturing technique for plastic materials is Fused Deposition Modelling (FDM). The FDM technology has gained interest in industry for a wide range of applications, especially today when large number of different materials on the market are available. There are many different manufacturers for the same FDM material where the difference in price goes up to 50%. This experimental study investigates possible difference in strength of the 3D printed PLA material of five different manufacturers. All specimens are 3D printed on Ultimaker S5 printer with the same printing parameters, and they are all the same colour.


2018 ◽  
Vol 2018 (1) ◽  
pp. 000099-000103
Author(s):  
William A. Goodman

Abstract Goodman Technologies has been directly responsive to, and focused on, 3D printing and additive manufacturing techniques, and what it takes to manufacture in zero-gravity. During a NASA Phase I SBIR project, using a small multi-printhead machine, we showed that it was possible to formulate and 3D print silicon carbide into shapes appropriate for lightweight mirrors and structures at the production rate of 1.2 square-meter/day. Gradient lattice coupons with feature sizes on the order of 0.8mm were printed and were easily machined to very fine tolerances, ten-thousandths of an inch by Coastline Optics in Camarillo, CA. To further elaborate on the list of achievements, in Phase I, Team GT demonstrated three different ceramization techniques for 3D printing low areal cost, ultra-lightweight Silicon Carbide (SiC) mirrors and structures, radiation shielding, and electronics, several of which could be employed in microgravity The Goodman Technologies briefing presented at 2017 Mirror Technology Days “3D Printed Silicon Carbide Scalable to Meter-Class Segments for Far-Infrared Surveyor: NASA Contract NNX17CM29P along with sample coupons resulted in extreme interest from both Government and the Contractor communities. Our materials, which we call RoboSiC™, is suited for many other applications including heat sinks and radiation shielding for space electronics, and we have already started to make the first parts for these applications. The successful Phase I project suggests that we will meet or exceed all NASA requirements for the primary mirror of a Far-IR Surveyor such as the Origins Space Telescope (OST) and have a high probability solution for the LUVOIR Surveyor in time for the 2020 Decadal Survey. Results indicate that printing on the ground will achieve an areal density of 7.75 kg/square-meter (~39% of a James Webb Space Telescope (JWST) beryllium segment), a cost to print of $60K/segment, and an optical surface that has nanometer-scale tolerances. Printing in the microgravity environment of space we have the potential to achieve an areal density of 1.0–2.0 kg/square meter (<10% of a JWST beryllium segment), with a cost to print of ~$10K/segment. The areal density is 2–15 times better than the NASA goal of 15 kg/square meter, and the costs are substantially better than the NASA goal of $100K/square meter. The encapsulated gradient lattice construction provides a uniform CTE throughout the part for dimensional stability, incredible specific stiffness, and the added benefit of cryo-damping. For the extreme wavefront control required by the Large UV/Optical/IR Surveyor (LUVOIR) the regularly spaced lattice construction should also provide deterministic mapping of any optical distortions directly to the regular actuator spacing of a deformable mirror (DM). Some of our processes will also allow for direct embedding of electronics for active structures and segments. Encapsulation of the lattice structures will allow for actively cooling with helium for unprecedented low emissivity and thermal control. Several decades of experience and testing with SiC have shown that our materials will survive, nay thrive in, the most extreme Space, Cryogenic, Laser and Nuclear Environments.


2020 ◽  
Vol 44 (2) ◽  
pp. 69-73
Author(s):  
Paul D. Bishop ◽  
Thomas Fultz ◽  
Lisa Smith ◽  
Ryan S. Klatte ◽  
Francis Loth ◽  
...  

Three-dimensional (3D) printing of anatomical structures has yielded valuable models for simulation, education, and surgical planning applications. Applications for 3D printing have continued to expand to include some ultrasound applications. The goal of this effort was to evaluate if a 3D printed model of a superficial femoral artery (SFA) would have realistic ultrasound characteristics. A computed tomography scan was 3D reconstructed and segmented using TeraRecon Aquarius Intuition software (TeraRecon, Foster City, California) to obtain an atherosclerotic SFA geometry. Both the lumen geometry and calcified plaque geometry of the SFA were exported as a stereolithographic (STL) file. The STL file was printed with An Object350 Connex 3D System using 2 different materials selected based on published elastic modulus data. VeroWhite was selected for the calcified plaque and TangoPlus Clear was selected for the artery wall. After printing, the SFA model was imaged in a water bath with a Phillips IU22 duplex ultrasound console and L12-9 ultrasound probe. Ultrasound imaging of the SFA model yielded grayscale views of artery geometry. Lumen geometry of the SFA model was similar to the actual artery geometry. Ultrasound was able to discern between the 3D print materials and visualize regions with stenosis. Suboptimal ultrasound parameters of echogenicity and wave velocity noted to differ from biological tissue. Total 3D print material cost was estimated at below $20. Although the 3D printed model did not have fully accurate ultrasound characteristics, it still provided realistic imaging. With further research, 3D printed models may offer a low-cost alternative for ultrasound phantoms.


Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1893 ◽  
Author(s):  
Přemysl Menčík ◽  
Radek Přikryl ◽  
Ivana Stehnová ◽  
Veronika Melčová ◽  
Soňa Kontárová ◽  
...  

This paper explores the influence of selected commercial plasticizers structure, which are based on esters of citric acid, on mechanical and thermal properties of Poly(3-hydroxybutyrate)/Poly(lactic acid)/Plasticizer biodegradable blends. These plasticizers were first tested with respect to their miscibility with Poly(3-hydroxybutyrate)/Poly(lactic acid) (PHB/PLA) blends using a kneading machine. PHB/PLA/plasticizer blends in the weight ratio (wt %) of 60/25/15 were then prepared by single screw and corotating meshing twin screw extruders in the form of filament for further three-dimensional (3D) printing. Mechanical, thermal properties, and shape stability (warping effect) of 3D printed products can be improved just by the addition of appropriate plasticizer to polymeric blend. The goal was to create new types of eco-friendly PHB/PLA/plasticizers blends and to highly improve the poor mechanical properties of neat PHB/PLA blends (with majority of PHB) by adding appropriate plasticizer. Mechanical properties of plasticized blends were then determined by the tensile test of 3D printed test samples (dogbones), as well as filaments. Measured elongation at break rapidly enhanced from 21% for neat non-plasticized PHB/PLA blends (reference) to 328% for best plasticized blends in the form of filament, and from 5% (reference) to 187% for plasticized blends in the form of printed dogbones. The plasticizing effect on blends was confirmed by Modulated Differential Scanning Calorimetry. The study of morphology was performed by the Scanning Electron Microscopy. Significant problem of plasticized blends used to be also plasticizer migration, therefore the diffusion of plasticizers from the blends after 15 days of exposition to 110 °C in the drying oven was investigated as their measured weight loss. Almost all of the used plasticizers showed meaningful positive softening effects, but the diffusion of plasticizers at 110 °C exposition was quite extensive. The determination of the degree of disintegration of selected plasticized blend when exposed to a laboratory-scale composting environment was executed to roughly check the “biodegradability”.


Author(s):  
Yifan Yang ◽  
Yutaka Ohtake ◽  
Hiromasa Suzuki

Abstract Making arts and crafts is an essential application of 3D printing. However, typically, 3D printers have limited resolution; thus, the perceptual quality of the result is always low, mainly when the input mesh is a relief. To address this problem using existing 3D printing technology, we only operate the shape of the input triangle mesh. To improve the perceptual quality of a 3D printed product, we propose an integrated mesh processing that comprises feature extraction, 3D print preview, feature preservation test, and shape enhancement. The proposed method can identify and enlarge features that need to be enhanced without large-scale deformation. Besides, to improve ease of use, intermediate processes are visualized via user interfaces. To evaluate the proposed method, the processed triangle meshes are 3D printed. The effectiveness of the proposed approach is confirmed by comparing photographs of the original 3D prints and the enhanced 3D prints.


2014 ◽  
Vol 29 (S2) ◽  
pp. S42-S47 ◽  
Author(s):  
Werner Kaminsky ◽  
Trevor Snyder ◽  
Jennifer Stone-Sundberg ◽  
Peter Moeck

Ongoing software developments for creating three-dimensional (3D) printed crystallographic models seamlessly from Crystallographic Information Framework (CIF) data (*.cif files) are reported. Color versus monochrome printing is briefly discussed. Recommendations are made on the basis of our preliminary printing efforts. A brief outlook on new materials for 3D printing is given.


Author(s):  
Frank Celentano ◽  
Nicholas May ◽  
Edward Simoneau ◽  
Richard DiPasquale ◽  
Zahra Shahbazi ◽  
...  

Professional musicians today often invest in obtaining antique or vintage instruments. These pieces can be used as collector items or more practically, as performance instruments to give a unique sound of a past music era. Unfortunately, these relics are rare, fragile, and particularly expensive to obtain for a modern day musician. The opportunity to reproduce the sound of an antique instrument through the use of additive manufacturing (3D printing) can make this desired product significantly more affordable. 3D printing allows for duplication of unique parts in a low cost and environmentally friendly method, due to its minimal material waste. Additionally, it allows complex geometries to be created without the limitations of other manufacturing techniques. This study focuses on the primary differences, particularly sound quality and comfort, between saxophone mouthpieces that have been 3D printed and those produced by more traditional methods. Saxophone mouthpieces are commonly derived from a milled blank of either hard rubber, ebonite or brass. Although 3D printers can produce a design with the same or similar materials, they are typically created in a layered pattern. This can potentially affect the porosity and surface of a mouthpiece, ultimately affecting player comfort and sound quality. To evaluate this, acoustic tests will be performed. This will involve both traditionally manufactured mouthpieces and 3D prints of the same geometry created from x-ray scans obtained using a ZEISS Xradia Versa 510. The scans are two dimensional images which go through processes of reconstruction and segmentation, which is the process of assigning material to voxels. The result is a point cloud model, which can be used for 3D printing. High quality audio recordings of each mouthpiece will be obtained and a sound analysis will be performed. The focus of this analysis is to determine what qualities of the sound are changed by the manufacturing method and how true the sound of a 3D printed mouthpiece is to its milled counterpart. Additive manufacturing can lead to more inconsistent products of the original design due to the accuracy, repeatability and resolution of the printer, as well as the layer thickness. In order for additive manufacturing to be a common practice of mouthpiece manufacturing, the printer quality must be tested for its precision to an original model. The quality of a 3D print can also have effects on the comfort of the player. Lower quality 3D prints have an inherent roughness which can cause discomfort and difficulty for the musician. This research will determine the effects of manufacturing method on the sound quality and overall comfort of a mouthpiece. In addition, we will evaluate the validity of additive manufacturing as a method of producing mouthpieces.


2018 ◽  
Vol 12 (1) ◽  
Author(s):  
Aimée Sakes ◽  
Kevin Hovland ◽  
Gerwin Smit ◽  
Jo Geraedts ◽  
Paul Breedveld

In current bipolar electrosurgical instruments, a high frequency electrical sinusoidal wave is passed through the patient's body from an active electrode to the return electrode to cut, coagulate, or desiccate tissues. Even though current bipolar electrosurgical instruments have proven effective in minimizing blood loss, advancement is needed to allow for improved dexterity and adaptability. With current advances in three-dimensional (3D)-print processes and its integration in the medical field, it has become possible to manufacture patient-and operation-specific instruments. In this study, we introduce the first 3D-printed steerable bipolar grasper (◻ 5 mm) for use in minimal invasive surgery. The grasper significantly improves dexterity by the addition of two planar joints allowing for ±65 deg for sideways and ±85 deg for up- and downward movement. The joints enable a significantly higher bending stiffness, 4.0 N/mm for joint 1 and 4.4 N/mm for joint 2, than that of currently available steerable instruments. The tip consists of two metallic movable jaws that can be opened and closed with angles up to 170 deg and allows for grasping and coagulating of tissues; reaching tissue temperatures of over 75 °C for an activation time of ∼5 s, respectively. In order to actuate the joint, tip, and electrosurgical system, as well as to tension the steering cables, a ring handle was designed. In summary, the 3D-printed steerable bipolar grasper provides the surgeon with electrosurgical capabilities, improved dexterity, improved stiffness, and the versatility that is needed to provide patient- and operation-specific care.


2021 ◽  
Vol 22 (23) ◽  
pp. 12721
Author(s):  
Arun Arjunan ◽  
John Robinson ◽  
Ahmad Baroutaji ◽  
Alberto Tuñón-Molina ◽  
Miguel Martí ◽  
...  

COVID-19 pandemic and associated supply-chain disruptions emphasise the requirement for antimicrobial materials for on-demand manufacturing. Besides aerosol transmission, SARS-CoV-2 is also propagated through contact with virus-contaminated surfaces. As such, the development of effective biofunctional materials that can inactivate SARS-CoV-2 is critical for pandemic preparedness. Such materials will enable the rational development of antiviral devices with prolonged serviceability, reducing the environmental burden of disposable alternatives. This research reveals the novel use of Laser Powder Bed Fusion (LPBF) to 3D print porous Cobalt-Chromium-Molybdenum (Co-Cr-Mo) superalloy with potent antiviral activity (100% viral inactivation in 30 min). The porous material was rationally conceived using a multi-objective surrogate model featuring track thickness (tt) and pore diameter (ϕd) as responses. The regression analysis found the most significant parameters for Co-Cr-Mo track formation to be the interaction effects of scanning rate (Vs) and laser power (Pl) in the order PlVs>Vs>Pl. Contrastively, the pore diameter was found to be primarily driven by the hatch spacing (Sh). The study is the first to demonstrate the superior antiviral properties of 3D printed Co-Cr-Mo superalloy against an enveloped virus used as biosafe viral model of SARS-CoV-2. The material significantly outperforms the viral inactivation time of other broadly used antiviral metals such as copper and silver, as the material’s viral inactivation time was from 5 h to 30 min. As such, the study goes beyond the current state-of-the-art in antiviral alloys to provide extra protection to combat the SARS-CoV-2 viral spread. The evolving nature of the COVID-19 pandemic brings new and unpredictable challenges where on-demand 3D printing of antiviral materials can achieve rapid solutions while reducing the environmental impact of disposable devices.


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