scholarly journals Pomelo Peel-Inspired 3D-Printed Porous Structure for Efficient Absorption of Compressive Strain Energy

2022 ◽  
Author(s):  
Baisong Yang ◽  
Wenhui Chen ◽  
Renlong Xin ◽  
Xiaohong Zhou ◽  
Di Tan ◽  
...  
Keyword(s):  
Porous Structure ◽  
Deformation Behavior ◽  
Compressive Strain ◽  
High Energy ◽  
Pomelo Peel ◽  
Polyether Ether Ketone ◽  
Element Simulation ◽  
Quantitative Understanding ◽  
3D Printed ◽  
Free Falling

AbstractThe porous structure in pomelo peel is believed to be responsible for the protection of its fruit from damage during the free falling from a tree. The quantitative understanding of the relationship between the deformation behavior and the porous structure could pave the way for the design of porous structures for efficient energy absorption. Here, a universal feature of pore distribution in pomelo peels along the radial direction is extracted from three varieties of pomelos, which shows strong correlation to the deformation behavior of the peels under compression. Guided by the porous design found in pomelo peels, porous polyether-ether-ketone (PEEK) cube is additively manufactured and possesses the highest ability to absorb energy during compression as compared to the non-pomelo-inspired geometries, which is further confirmed by the finite element simulation. The nature-optimized porous structure revealed here could guide the design of lightweight and high-energy-dissipating materials/devices.

Analysis of Voltage Contrast in Secondary Electron Images Using a High-Energy Electron Spectrometer

2019 ◽  
Author(s):  
Natsuko Asano ◽  
Shunsuke Asahina ◽  
Natasha Erdman
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Sample Surface ◽  
High Energy ◽  
Secondary Electrons ◽  
Analysis Technique ◽  
Quantitative Understanding ◽  
Voltage Contrast ◽  
Acceleration Voltage ◽  
Failure Localization

Abstract Voltage contrast (VC) observation using a scanning electron microscope (SEM) or a focused ion beam (FIB) is a common failure analysis technique for semiconductor devices.[1] The VC information allows understanding of failure localization issues. In general, VC images are acquired using secondary electrons (SEs) from a sample surface at an acceleration voltage of 0.8–2.0 kV in SEM. In this study, we aimed to find an optimized electron energy range for VC acquisition using Auger electron spectroscopy (AES) for quantitative understanding.

Developments in the Field of Rapid Prototype Production

2008 ◽  
Vol 589 ◽  
pp. 421-425 ◽  
Author(s):  
Norbert Krisztián Kovács ◽  
József Gábor Kovács
Keyword(s):  
Mechanical Strength ◽  
Porous Structure ◽  
Epoxy Resin ◽  
Rapid Prototype ◽  
Post Treatment ◽  
3D Printer ◽  
Infiltration Depth ◽  
3D Printed ◽  
The Common ◽  
Polymer Engineering

Characteristics of 3D printed specimens are porous structure and low mechanical strength. Due to porous structure post treatment is possible, and in most cases infiltration with an epoxy resin, wax or cyanoacrylate material takes place. As a result of post treatment, the mechanical strength can be increased by 100%, although this is strongly influenced by the infiltration depth that depends on the porous structure and the resin viscosity. In the framework of the common research of the Department of Polymer Engineering, BME and Varinex Zrt. the applicability of a 3D printer is examined in the field of direct tool making. As the first step, the resin uptake ability of specimens prepared with a Z810 3D printer is examined.

scholarly journals Towards a quantitative understanding of period-doubling wrinkling patterns occurring in film/substrate bilayer systems

2015 ◽  
Vol 471 (2173) ◽  
pp. 20140695 ◽  
Author(s):  
Yan Zhao ◽  
Yanping Cao ◽  
Wei Hong ◽  
M. Khurram Wadee ◽  
Xi-Qiao Feng
Keyword(s):  
Potential Energy ◽  
Critical Strain ◽  
Deformation Behaviour ◽  
Compressive Strain ◽  
Period Doubling ◽  
Careful Examination ◽  
Deformation State ◽  
Quantitative Understanding ◽  
Surface Patterns ◽  
Film Substrate

Compression of a stiff film on a soft substrate may lead to surface wrinkling when the compressive strain reaches a critical value. Further compression may cause a wrinkling–folding transition, and the sinusoidal wrinkling mode can then give way to a period-doubling bifurcation. The onset of the primary bifurcation has been well understood, but a quantitative understanding of the secondary bifurcation remains elusive. Our theoretical analysis of the branching of surface patterns reveals that the wrinkling–folding transition depends on the wrinkling strain and the prestrain in the substrate. A characteristic strain in the substrate is adopted to determine the correlation among the critical strain of the period-doubling mode, the wrinkling strain and the prestrain in an explicit form. A careful examination of the total potential energy of the system reveals that beyond the critical strain of period-doubling, the sinusoidal wrinkling mode has a higher potential energy in comparison with the period-doubling mode. The critical strain of the period-doubling mode strongly depends on the deformation state of the hyperelastic solid, indicating that the nonlinear deformation behaviour of the substrate plays a key role here. The results reported here on the one hand provide a quantitative understanding of the wrinkling–folding transition observed in natural and synthetic material systems and on the other hand pave the way to control the wrinkling mode transition by regulating the strain state in the substrate.

scholarly journals Is three-dimensional–printed custom-made ultra-short stem with a porous structure an acceptable reconstructive alternative in peri-knee metaphysis for the tumorous bone defect?

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Jie Wang ◽  
Jingjing An ◽  
Minxun Lu ◽  
Yuqi Zhang ◽  
Jingqi Lin ◽  
...  
Keyword(s):  
Porous Structure ◽  
Aseptic Loosening ◽  
Bone Defect ◽  
Short Stem ◽  
Leg Length ◽  
Musculoskeletal Tumor Society ◽  
Custom Made ◽  
Orthopedic Oncology ◽  
3D Printed

Abstract Background Long-lasting reconstruction after extensive resection involving peri-knee metaphysis is a challenging problem in orthopedic oncology. Various reconstruction methods have been proposed, but they are characterized by a high complication rate. The purposes of this study were to (1) assess osseointegration at the bone implant interface and correlated incidence of aseptic loosening; (2) identify complications including infection, endoprosthesis fracture, periprosthetic fracture, leg length discrepancy, and wound healing problem in this case series; and (3) evaluate the short-term function of the patient who received this personalized reconstruction system. Methods Between September 2016 and June 2018, our center treated 15 patients with malignancies arising in the femur or tibia shaft using endoprosthesis with a 3D-printed custom-made stem. Osseointegration and aseptic loosening were assessed with digital tomosynthesis. Complications were recorded by reviewing the patients’ records. The function was evaluated with the 1993 version of the Musculoskeletal Tumor Society (MSTS-93) score at a median of 42 (range, 34 to 54) months after reconstruction. Results One patient who experienced early aseptic loosening was managed with immobilization and bisphosphonates infusion. All implants were well osseointegrated at the final follow-up examination. There are two periprosthetic fractures intraoperatively. The wire was applied to assist fixation, and the fracture healed at the latest follow-up. Two patients experienced significant leg length discrepancies. The median MSTS-93 score was 26 (range, 23 to 30). Conclusions A 3D-printed custom-made ultra-short stem with a porous structure provides acceptable early outcomes in patients who received peri-knee metaphyseal reconstruction. With detailed preoperative design and precise intraoperative techniques, the reasonable initial stability benefits osseointegration to osteoconductive porous titanium, and therefore ensures short- and possibly long-term durability. Personalized adaptive endoprosthesis, careful intraoperative operation, and strict follow-up management enable effective prevention and treatment of complications. The functional results in our series were acceptable thanks to reliable fixation in the bone-endoprosthesis interface and an individualized rehabilitation program. These positive results indicate this device series can be a feasible alternative for critical bone defect reconstruction. Nevertheless, longer follow-up is required to determine whether this technique is superior to other forms of fixation.

scholarly journals Estimation of sinking velocities using free-falling dynamically scaled models: foraminifera as a test case

2020 ◽  
Author(s):  
Matthew Walker ◽  
Stuart Humphries ◽  
Rudi Schuech
Keyword(s):  
Planktonic Foraminifera ◽  
Physical Models ◽  
Dynamic Scaling ◽  
Test Case ◽  
Dimensionless Numbers ◽  
Settling Particles ◽  
Extant Species ◽  
3D Printed ◽  
Sinking Velocities ◽  
Free Falling

AbstractThe velocity of settling particles is an important determinant of distribution in extinct and extant species with passive dispersal mechanisms, such as plants, corals, and phytoplankton. Here we adapt dynamic scaling, borrowed from engineering, to determine settling velocities. Dynamic scaling leverages physical models with relevant dimensionless numbers matched to achieve similar dynamics to the original object. Previous studies have used flumes, wind tunnels, or towed models to examine fluid flows around objects with known velocities. Our novel application uses free-falling models to determine the unknown sinking velocities of planktonic foraminifera – organisms important to our understanding of the Earth’s current and historic climate. Using enlarged 3D printed models of microscopic foraminifera tests, sunk in viscous mineral oil to match their Reynolds numbers and drag coefficients, we predict sinking velocities of real tests in seawater. This method can be applied to study other settling particles such as plankton, spores, or seeds.Summary StatementWe developed a novel method to determine the sinking velocities of biologically important microscale particles using 3D printed scale models.

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