An investigation of the strength and stiffness of weight-saving sandwich beams with CFRP face sheets and seven 3D printed cores

2021 ◽  
Vol 257 ◽  
pp. 113391
Author(s):  
Ahmad W. Alshaer ◽  
Daniel J. Harland
1991 ◽  
Vol 31 (1) ◽  
pp. 1-7 ◽  
Author(s):  
K. Lingaiah ◽  
B. G. Suryanarayana

2020 ◽  
Vol 26 (4) ◽  
pp. 699-706
Author(s):  
Feras Korkees ◽  
James Allenby ◽  
Peter Dorrington

Purpose 3D printing of composites has a high degree of design freedom, which allows for the manufacture of complex shapes that cannot be achieved with conventional manufacturing processes. This paper aims to assess the design variables that might affect the mechanical properties of 3D-printed fibre-reinforced composites. Design/methodology/approach Markforged Mark-Two printers were used to manufacture samples using nylon 6 and carbon fibres. The effect of fibre volume fraction, fibre layer location and fibre orientation has been studied using three-point flexural testing. Findings The flexural strength and stiffness of the 3D-printed composites increased with increasing the fibre volume fraction. The flexural properties were altered by the position of the fibre layers. The highest strength and stiffness were observed with the reinforcement evenly distributed about the neutral axis of the sample. Moreover, unidirectional fibres provided the best flexural performance compared to the other orientations. 3D printed composites also showed various failure modes under bending loads. Originality/value Despite multiple studies available on 3D-printed composites, there does not seem to be a clear understanding and consensus on how the location of the fibre layers can affect the mechanical properties and printing versatility. Therefore, this study covered this design parameter and evaluated different locations in terms of mechanical properties and printing characteristics. This is to draw final conclusions on how 3D printing may be used to manufacture cost-effective, high-quality parts with excellent mechanical performance.


2017 ◽  
Vol 21 ◽  
pp. 294-300
Author(s):  
Iuliana Dupir ◽  
Nicolae Ţăranu ◽  
Cristina Vlădoiu ◽  
Dragoş Ungureanu ◽  
Vlad Lupăşteanu

Sandwich elements with structural functions are widely used in engineering applications, offering outstanding advantages, such as high strength and stiffness compared to its low specific weight. The sandwich elements consist in two stiff and thin faces, separated by a thick and lightweight core. A numerical analysis is performed in this paper, in order to evaluate the flexural structural response of sandwich beams with foam core and various facing materials. It has been noticed that the deflections decrease when the stiffness of the facings increase. The results are represented in terms of maximum deflections and direct stress distributions.


Author(s):  
A. A. Skleznev ◽  
A. A. Babichev ◽  
V. N. Borisov

The paper proposes a variant of the design of an adapter for several payloads made of composite materials. A computational experiment was carried out using the FEM, a comparison with existing structures is made, and the technology for manufacturing of such structures is described. Significant weight saving of the adapter design is shown in comparison with existing analogs while maintaining the same strength and stiffness margins.


Robotics ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 49
Author(s):  
Daniel Ong U Jing ◽  
Declan Devine ◽  
John Lyons

This research furthers the practice of designing and manufacturing End of Arm Tooling (EOAT) by utilizing a low cost additive manufacturing Fused Filament Fabrication (FFF) technique to enable tool weight saving and provision of low cost EOATs on demand, thereby facilitating zero inventory lean manufacturing. The materials used in this research for the fabrication of the EOAT parts were Acrylonitrile butadiene styrene (ABS) and nylon with infill densities of 20% and 100%. Three-point flexural tests were performed to determine the differences in strength and stiffness between varying polymers, infill ratios, and a standard metal part. Additionally, potential weight savings were identified and challenges with utilizing low cost FFF technologies are outlined. A motion of programmed trajectories was executed utilizing a standard 6-axis robot and the power consumption was evaluated. This study demonstrates the utility of using thermoplastic material with the fabrication of 3D printed parts used in EOATs.


2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0050
Author(s):  
Joshua Veenstra ◽  
Peter Gustafson ◽  
Cody Bearden ◽  
James Jastifer

Category: Basic Sciences/Biologics Introduction/Purpose: There are many screw and thread designs available to the foot and ankle surgeon for bone fixation. Comparing screws between companies is difficult because properties including core diameter, thread diameter, and pitch confound direct comparisons. There is a paucity of literature on comparative mechanical properties of various screw designs including variable pitch screws and tapered screws. The purpose of this study was to determine the effect of varying thread pitch and/or tapering a screws core diameter. Our hypothesis was that variable pitch screws and tapered screws would have decreased strength compared to screws with constant diameter and constant pitch. Methods: 3D metal printing technology was used to manufacture screws that varied in only the test variables. Four different screws designs were created including variable and constant pitch screws in both straight and tapered diameter versions. These screws were pulled out of synthetic bone at a constant rate while force was measured. Pull out strength and stiffness was calculated for each screw. A generalized linear model and ANOVA were completed to assess the effect on pull out strength and stiffness of the pitch and taper variables. Results: The pull out strength of the constant pitch screws (304.9N+-25.3 N, p<0.001) was significantly greater than the variable pitch screws (259.7N+-23.4 N). The pull out strength was also significantly greater for screws with a tapered diameter (305.4N+- 24.1 N) than a constant diameter (259.1N+-23.5 N, p<0.001). Tapered diameter variable pitch screws had the largest stiffness overall (mean stiffness 556.6 N/mm), which was greater than all other screw designs (p=0.001). The difference in stiffness between all screws with either constant pitch or constant diameter was not statistically significant (p=0.060). Conclusion: The pull out strength is significantly greater for screws with a constant pitch than for a variable pitch and greater for a tapered diameter than a constant diameter. The clinical significance of this study is that it provides data on the effects that thread design and tapering have on the pullout strength of screws providing some evidence that variable pitch screws may have lower pull out strength than constant pitch screws. Utilizing 3D printed screws allowed for the control of all other variables, which may otherwise confound the comparison of different commercially available screws.


2021 ◽  
Vol 161 ◽  
pp. 107471
Author(s):  
Chenxi Peng ◽  
Kate Fox ◽  
Ma Qian ◽  
H. Nguyen-Xuan ◽  
Phuong Tran

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