This paper presents the prospect of 3D printing technology to generate artificial soil analogs with the goal of modeling the mechanical behavior of coarse-grained soils. 3D X-ray CT scans of natural angular and rounded sand particles have been used to generate angular and rounded particle analogs using the polyjet 3D printing technology. A comparison of the scanned natural sand particles and the 3D printed particles demonstrates the ability of 3D printing technology to reproduce the shape and size of the sand particles. The results of oedometer compression tests on the angular and rounded natural and 3D printed particles are used to demonstrate the effect of constituent material (i.e. quartz versus polymer) stiffness on the measured soil compressibility and investigate the normalization of the response using the Hertz contact theory. The results provided in this paper also include comparison of the small-strain moduli–mean effective stress relationship obtained for the natural and 3D printed soils. This paper illustrates the potential use of 3D printed analogs to model the mechanical behavior of coarse-grained soils and identifies future research needs for implementation of the proposed normalization scheme within the critical state soil mechanics framework.
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Grayscale Digital Light Processing and Post‐Treatment for the Fabrication of 3D‐Printed Polymer Blends
3D‐printed polymer blends with programmable mechanical and compositional heterogeneity were fabricated using grayscale digital light processing by spatially modulating the intensity of light during printing and swelling the resulting part with a second monomer. A rubbery poly(ethylene glycol) diacrylate functionally graded print is variably swollen with acrylamide monomer as a function of crosslinking density. Following a secondary polymerization, a 3D‐printed functionally graded blend with regions of varying composition and stiffness was formed. A deterministic model for polymer conversion informs printing conditions to correspond with predicted material properties based upon local volume fractions of the two materials. Upon the secondary polymerization, two networks are present within the printed structure including glassy and rubbery regions. The compressive moduli of local regions within prints ranges from 76 to 200 MPa and measured moduli of the structures agree with predicted values acquired using finite element analysis. A lattice structure with prescribed local stiffness printed using grayscale exposures deforms differentially when compressed. Advantageously, local dimensional deformations caused by the removal of the unreacted printing monomer are eliminated due to the introduction of the second polymer. This method provides predictive control over local mechanical properties and high shape precision while maintaining the simplicity of vat photopolymerization.
- Award ID(s):
- 1826454
- NSF-PAR ID:
- 10372032
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Engineering Materials
- Volume:
- 24
- Issue:
- 8
- ISSN:
- 1438-1656
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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