3D-printed Column Research Articles

A Feasibility Study on the Lateral Behavior of a 3D-Printed Column for Application in a Wind Turbine Tower

Although 3D printing technology has been applied worldwide, the problem of connecting a printed structure and a foundation has rarely been examined. In particular, loads in the horizontal direction, such as wind loads and earthquake loads, can significantly affect the stability of a printed structure. Therefore, in this study, the effect of lateral loads on printed columns that were connected to a foundation by two types of connectors was investigated. A steel angle with bolts and couplers was used to connect the printed column to a concrete footing. In addition, two types of lateral reinforcement were applied to the printed column to enhance its bonding strength and shear resistance. The lateral reinforcements were attached to the interface of the printed layers at distances of 100 and 200 mm to investigate the effect of lateral reinforcement distance on the lateral behavior of the printed column. The results showed that the use of couplers as connections between the columns and foundation significantly improved the load capacity. Furthermore, the effects of the lateral reinforcement types and lateral reinforcement distances were assessed.

Performance of 3D printed columns using self-sensing cementitious composites

Self-sensing cementitious composites can be used as an economical method of structural health monitoring. This is achieved by using the piezoresistivity effect to assist in the detection of defects and enabling repairs to be conducted early which can therefore avoid structural failures. This study uses an established self-sensing cementitious composite mix to 3D print column to examine its structural performance and sensing capabilities in components of large-scale concrete structures. An extrusion-based 3D printer was used to print hollow square column segments. These segments were then joined and filled with steel rebar reinforcement and cast concrete. Another column was created using mould cast concrete for comparison. The specimens were tested under static axial compression to determine their compressive properties, electrical resistivity and piezoresistivity response. The results showed that the 3D printed column performance can be monitored using the self-sensing composite until the printed shell cracks. The 3D printed column did show superior electrical properties with a lower electrical resistance of 274.2 Ω.cm. These results indicate that a different manufacturing approach to creating a 3D printed column should utilise the advantages of 3D printing for use in self-sensing concrete structures.

Enhancement of devolatilization performance in a rotating packed bed with different packing structures

• The 3D-printed mesh packing with drop-shaped fibers (PMP-D) was manufactured. • The PMP-D was employed to enhance the devolatilization performance in RPB. • Compared with traditional SMP, the η and K L a of PMP-D was drastically improved. • Correlations to predict K L a were established with deviations less than ±20%. The devolatilization of volatile organic compounds (VOCs) from the viscous liquid like polymers was necessary but of great challenge caused by the high viscosity. In this work, different packing structures were manufactured in a rotating packed bed (RPB), including the stainless steel wire mesh packing (SMP), 3D-printed column packing (PCP), 3D-printed mesh packing with circular fibers (PMP-C), and 3D-printed mesh packing with drop-shaped fibers (PMP-D). The devolatilization performance of the RPB was investigated with the acetone-silicon oil working system. Results indicated that modifying the fiber shape of packing effectively intensified the devolatilization in the RPB. The removal efficiency ( η ) and volumetric mass transfer coefficient ( K L a ) of the PMP-D were dramatically larger than the other three packings. Compared the PMP-D with the traditional SMP, the maximum η was enhanced from 40% to 50%, and the increment of K L a was 50% on average. The correlations to predict K L a were established, and the deviations from the experimental results were less than ± 20%.

3D-printed ordered bed structures for chromatographic purification of enveloped and non-enveloped viral particles

In the last few decades we have witnessed a rapid advance in the design of new biotherapeutic products using viral particles. The current limitations of manufacturing these particles are often associated with their purification processes. Additive manufacturing opened the possibility of printing 3D porous chromatographic structures to be used in the bio-separation field. Here, we report the production and use of 3D-printed cellulose chromatographic columns functionalized with two different ligands: diethylaminoethyl (DEAE) and hydroxyapatite for the purification of oncolytic adenovirus and lentiviral vectors. Porous beds with ordered channel structures can be manufactured to achieve separations that are efficient and tailored to the target products. While common chromatographic beads are based on non-ordered bed structures, in this work we explore the use of a triply periodic minimal surface, the Schoen Gyroid, to create bed structures with a channel size of 300 µm in diameter. The dynamic binding capacity (DBC) obtained for non-enveloped oncolytic adenovirus using the 3D-printed DEAE column (1.9 × 1010 viral genomes per millilitre) was consistent with the reported values in the literature for this virus particle. We also demonstrate that by using these 3D-printed chromatographic supports, oncolytic adenoviruses were successfully purified with a recovery yield of 69 ± 6%, while maintaining their size and shape as observed by electron microscopy analysis. For lentiviral vectors, a DBC of 2 × 109 physical particles per millilitre was achieved for the DEAE column. Moreover, these enveloped viruses were purified using this 3D-printed column with a recovery yield of 57% of transducing units. These findings suggest, with advancements, 3D printing technologies applied in the viral vector manufacturing field could improve downstream process efficiency.

3D-Printed Column with Porous Monolithic Packing for Online Solid-Phase Extraction of Multiple Trace Metals in Environmental Water Samples

In this study, we used a multimaterial three-dimensional printing (3DP) technology and porous composite filaments (Lay-Fomm, Gel-Lay, and Lay-Felt) to fabricate solid phase extraction (SPE) columns for the enhanced extraction of multiple metal ions. When employed as sample pretreatment devices in an automatic flow injection analysis/inductively coupled plasma mass spectrometry (ICP-MS) system, these 3D-printed SPE columns performed the near-complete extractions of Mn, Co, Ni, Cu, Zn, Cd, and Pb ions from natural water samples prior to ICP-MS determination. After optimizing the column fabrication, the extraction conditions, and the automatic analysis system, the column packed with the porous composite Lay-Fomm 40 was found to provide the highest extraction performance-the extraction efficiencies of the listed metal ions were all greater than 99.2%, and the detection limits of the method ranged from 0.3 to 6.7 ng L-1. The detection of these metal ions in several reference materials (CASS-4, SLEW-3, 1640a, and 1643f) validated the reliability of this method; spike analyses of collected water samples (groundwater, river water, and seawater) demonstrated the applicability of the method. The nature of the printing materials enhanced the analytical performance of 3D-printed sample pretreatment devices. Such approaches will be useful to diversify the range of sample preparation schemes and analytical methods enabled by 3DP technologies.

3D-printed flow system for determination of lead in natural waters

The development of 3D printing in recent years opens up a vast array of possibilities in the field of flow analysis. In the present study, a new 3D-printed flow system has been developed for the selective spectrophotometric determination of lead in natural waters. This system was composed of three 3D-printed units (sample treatment, mixing coil and detection) that might have been assembled without any tubing to form a complete flow system. Lead was determined in a two-step procedure. A preconcentration of lead was first carried out on TrisKem Pb Resin located in a 3D-printed column reservoir closed by a tapped screw. This resin showed a high extraction selectivity for lead over many tested potential interfering metals. In a second step, lead was eluted by ammonium oxalate in presence of 4-(2-pyridylazo)-resorcinol (PAR), and spectrophotometrically detected at 520nm. The optimized flow system has exhibited a linear response from 3 to 120µgL−1. Detection limit, coefficient of variation and sampling rate were evaluated at 2.7µgL−1, 5.4% (n=6) and 4 sampleh−1, respectively. This flow system stands out by its fully 3D design, portability and simplicity for low cost analysis of lead in natural waters.

Dispersion behavior of 3D-printed columns with homogeneous microstructures comprising differing element shapes

We used additive manufacturing (3D printing) to create ordered porous beds from a range of geometric shapes, including truncated icosahedra (approximating spheres), tetrahedral, octahedral, triangular bipyramid, and stellar octangular particles. We show that the printed porous media were highly reproducible and had excellent fidelity in physically reproducing computer-aided design models, with differences between designed and experimentally measured particle locations within ±0.5%, and within 1.3% in terms of bed porosity. Experimental residence time distributions were measured and the reduced plate height, h, was determined under different reduced velocities (Peclet number, Pe=4–400). The results (using equivalent particle diameter to non-dimensionalize) show that, for the simple cubic (SC) arrangement, tetrahedral particles had a lower plate height (hmin=1.56) than all other particle shapes tested, including spherical particles. We also, for the first time, experimentally validated computational predictions of the performance of SC, body centered cubic (BCC) and face centered cubic (FCC) arrangements of spheres, confirming that FCC is indeed superior (hmin=1.12) to SC (hmin=1.62). We conclude that the capability offered by additive manufacturing in controlling not only packing configuration but also shape, position and orientation of the geometric elements within the porous bed may, in the future, play a fundamental role in the design of highly efficient 3D-printed columns.

Mechanical behavior of FRP sheets reinforced 3D elements printed with cementitious materials

A method to improve the mechanical behavior of 3D-printed elements is presented. 3D-printed elements are orthotropic and weak in their interlayers; thus, FRPs, which are easy-formed, light-weighted and high-strength, are ideal materials to enhance 3D-printed elements. To investigate the reinforcement effect, uniaxial compression tests were conducted on circular column specimens, and four-point flexural tests were conducted on beam specimens. The results indicated that wrapping 3D-printed columns with FRPs changed their failure modes from brittle to ductile, increased the peak loads that they could endure by 1427.2–1792.0% and increased the largest deformations they could achieve by 833.9–1171.3% using different numbers of layers and types of reinforcement. For the 3D-printed beams reinforced with FRPs, the bearing capacities were increased by 179.6–604.5%, and their flexure deflections at their mid-spans were increased by 40.8–225.8%. The failure modes of the 3D-printed beams were affected by numbers of layers and types of reinforcement. Additionally, finite element analyses were conducted to simulate the failure modes of the 3D-printed elements based on the maximum stress criterion. The results showed that the predicted failure locations corresponded with the experimental failure locations observed. According to this study, 3D-printed elements reinforced with FRP sheets showed potential for future development and applications in construction.

Small crack growth in mutiaxial fatigue: Reddy, S.C. and Fatemi, A. Proc. Conf. Advances in Fatigue Lifetime Predictive Techniques, San Francisco, California, USA, 24 Apr. 1990 276–298

The development of 3D printing in recent years opens up a vast array of possibilities in the field of flow analysis. In the present study, a new 3D-printed flow system has been developed for the selective spectrophotometric determination of lead in natural waters. This system was composed of three 3D-printed units (sample treatment, mixing coil and detection) that might have been assembled without any tubing to form a complete flow system. Lead was determined in a two-step procedure. A preconcentration of lead was first carried out on TrisKem Pb Resin located in a 3D-printed column reservoir closed by a tapped screw. This resin showed a high extraction selectivity for lead over many tested potential interfering metals. In a second step, lead was eluted by ammonium oxalate in presence of 4-(2-pyridylazo)-resorcinol (PAR), and spectrophotometrically detected at 520 nm. The optimized flow system has exhibited a linear response from 3 to 120 µg L−1. Detection limit, coefficient of variation and sampling rate were evaluated at 2.7 µg L−1, 5.4% (n=6) and 4 sample h−1, respectively. This flow system stands out by its fully 3D design, portability and simplicity for low cost analysis of lead in natural waters.