Boxception
            : Impact Resistance Structure Using 3D Printing

3D printing as a manufacturing method is gaining more popularity since 3D printing machines are becoming easily accessible. Especially in a prototyping process of a machine, they can be used, and complex parts with high quality surface finish can be manufactured in a timely manner. However, there is a need to study the effects of different manufacturing parameters on the materials properties of the finished parts. Specifically, this chapter explains the effects of six different process parameters on the impact resistance. In particular, print temperature, print speed, infill ratio, infill pattern, layer height, and print orientation parameters were studied, and their effects on impact resistance were measured experimentally. Moreover, the optimum values of the process parameters for impact resistance were found. This chapter provides an important guideline for 3D manufacturing in terms of impact resistance of the printed parts. Furthermore, by using this methodology the effects of different 3D printing process parameters on the other material, properties can be determined.

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Fine-Grained Polymer-Cement Basalt Fibrous Concrete for 3D Printing

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.299.227 ◽

2020 ◽

Vol 299 ◽

pp. 227-234

Author(s):

Valentina Anatolyevna Poluektova

Keyword(s):

3D Printing ◽

Impact Resistance ◽

Basalt Fiber ◽

Fine Grained ◽

Production Wastes ◽

Plastic Strength ◽

Fibrous Concrete ◽

High Crack ◽

Disperse Reinforcement ◽

High Plastic

The construction concrete printing requires new approaches at reinforcement performing. Only successful integration of the existing reinforcement systems will provide for the opportunity to design concrete structures and make objects with the help of additive technologies. The paper dwells upon the issues of possibilities and the efficiency of disperse reinforcement with basalt fibers. It presents a composition of a composite material for 3D printing of a type of fine-grained fibrous concretes with the required technological properties: a necessary plasticity and a high plastic strength for printing large-dimensioned items and structures without timbering by means of extrusion with a high material adhesion between the layers and controlled setting periods. The author studied a possibility to reclaim basalt fiber production wastes as a high-disperse fibrous filler for the reinforcement of polymer-modified concretes. The article provides the dependence of plastic strength on the fiber content in concrete. The authors consider the influence of components and the mechanism of modifying disperse particles of basalt fibrous concrete at obtaining the material for 3D printing. The obtained polymer-modified basal fibrous concrete has a good impact resistance, low water absorption and high crack resistance.

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Impact resistance of nacre-like composites diversely patterned by 3D printing

Composite Structures ◽

10.1016/j.compstruct.2020.111951 ◽

2020 ◽

Vol 238 ◽

pp. 111951 ◽

Cited By ~ 3

Author(s):

Kwonhwan Ko ◽

Suyeong Jin ◽

Sang Eon Lee ◽

Jung-Wuk Hong

Keyword(s):

3D Printing ◽

Impact Resistance

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Modulation of the PLLA Morphology through Racemic Nucleation to Reach Functional Properties Required by 3D Printed Durable Applications

Materials ◽

10.3390/ma14216650 ◽

2021 ◽

Vol 14 (21) ◽

pp. 6650

Author(s):

Doina Dimonie ◽

Silvia Mathe ◽

Manuela Maria Iftime ◽

Daniela Ionita ◽

Roxana Trusca ◽

...

Keyword(s):

3D Printing ◽

Polylactic Acid ◽

Functional Properties ◽

Impact Resistance ◽

Future Research ◽

Melt Blending ◽

Dsc Analysis ◽

Spectral Changes ◽

Alternative Means ◽

3D Printed

This paper presents an alternative means for enhancing the durability of poly (L-lactide) (PLLA) by racemic nucleation following stereo-complexation with a selected poly (D-lactide) (PLDA). The compounds are obtained by melt blending of a PLLA grade, previously designed for 3D printing but with a low heat deflection temperature and impact resistance, with grades of PLDA differing in their molecular weight (Mw), D-lactide content (DS) and concentration. Our method considered how to reveal the racemic nucleation caused by stereo-complexation and its influence on functional properties. The FTIR study we performed showed that, depending on Mw, DS and concentration of the stereo-complexer (PDLA) used, bigger or smaller spectral changes can occur. The stereo-complexation was confirmed by the DSC analysis and, for the selected compound, by the POM, SEM, AFM microscopies, functional property and shapeability as 3D printing filaments. All the obtained results sustain the idea that, if a PLLA with Mw of 4.5 × 104 g·mol−1 is modified with PDLA with a medium Mw of 11.6 × 104 g·mol−1, medium DS of 4% and 1% concentration, a racemic nucleation is possible. It produces a racemic polylactic acid (PDLLA) with improved durability and good shapeability as 3D printing filaments. These results are explicable if the dependence of the intermolecular interactions appears between the PLLA and stereo-complexer PDLA. To enlarge the durable applicability of racemic polylactic acid (PDLLA), future research should identify other parameters controling the PLA stereo-complexing as the intensifying the mobility of the macromolecules, the finding of the optimal recemic cristalization window.

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Manufacturing Capability Index of 3D Printing Parts for Impact Applications

Volume 5: Biomedical and Biotechnology ◽

10.1115/imece2020-23123 ◽

2020 ◽

Author(s):

Anne Schmitz

Keyword(s):

High Resolution ◽

3D Printing ◽

Brinell Hardness ◽

Weight Bearing ◽

Impact Resistance ◽

Process Capability ◽

Process Capability Index ◽

Impact Testing ◽

Capability Index ◽

The Impact

Abstract Three-dimensional (3D) printing with high-resolution stereolithography (SLA) has grown in popularity for creating personalized medical devices. 3D printing is now starting to expand to weight-bearing components, e.g. prosthetic feet, as data on the dynamic properties impact and fatigue is published in the literature. The next step towards using 3D printing in impact applications is to assess the capability of the high-resolution SLA process to manufacture components of uniform impact resistance. Because impact testing is destructive, a surrogate measure to check a part’s viability for resisting an impact load also needs to be established. Thirteen notched Izod specimens were printed on a Form2 SLA printer using the manufacturer’s clear V4, photocurable resin. Once all the specimens were printed, washed in isopropyl alcohol, and cured with ultraviolet light, the impact resistance was quantified using a pendulum impact tester in a notched Izod configuration. Then, the hardness of the specimens was quantified using a HBW 10/250 scale. The impact resistance of the clear, SLA polymer was 0.59 ± 0.14 ft-lb/in. With an upper standard limit of 0.53 ft-lb/in, the process capability index was 0.133. Impact resistance and Brinell hardness were not correlated with a Spearman coefficient of r = −0.108, p = 0.73. Since the process capability index was less than one, 3D printing with SLA polymers is not a viable manufacturing process for creating parts of consistent impact resistance. The current technology would lead to too many rejected parts. Also, Brinell hardness and impact strength were not related. Therefore, there is no non-destructive method to spot-check these components before use.

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Manufacturing Capability of 3D Printed Stereolithography Parts for Impact Applications

Journal of Engineering and Science in Medical Diagnostics and Therapy ◽

10.1115/1.4051892 ◽

2021 ◽

Author(s):

Anne Schmitz

Keyword(s):

High Resolution ◽

3D Printing ◽

Impact Load ◽

Dynamic Properties ◽

Weight Bearing ◽

Impact Resistance ◽

Three Dimensional ◽

Process Capability ◽

Impact Testing ◽

The Impact

Abstract Three-dimensional (3D) printing with high-resolution stereolithography (SLA) has grown in popularity for creating personalized medical devices. 3D printing is now starting to expand to weight-bearing components, e.g. prosthetic feet, as data on the dynamic properties impact and fatigue is published in the literature. The next step towards using 3D printing in impact applications is to assess the capability of the high-resolution SLA process to manufacture components of uniform impact resistance. Because impact testing is destructive, a surrogate measure to check a part's viability for resisting an impact load also needs to be established. Thirteen notched Izod specimens were printed on a Form2 SLA printer using the manufacturer's photocurable resins: clear, flexible, durable, and draft. Once all the specimens were printed, washed in isopropyl alcohol, and cured with ultraviolet light, the impact resistance was quantified using a pendulum impact tester in a notched Izod configuration. Then, the hardness of the specimens was quantified using a Shore durometer. The process capability indices of the impact resistance for the various polymers were 0.11 (clear), 0.43 (flexible), 0.65 (durable), and 1.07 (draft). Impact resistance and Shore durometer were only correlated for the flexible resin with a Spearman coefficient of r = 0.738, p < 0.005. Since the process capability index was so variable across materials, 3D printing with SLA polymers is not a viable manufacturing process for creating parts of consistent impact resistance. The current technology would lead to too many rejected parts.

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Tailoring Cellular Auxetics for Wearable Applications With Multimaterial 3D Printing

Volume 9: Mechanics of Solids, Structures and Fluids; NDE, Diagnosis, and Prognosis ◽

10.1115/imece2016-67556 ◽

2016 ◽

Cited By ~ 1

Author(s):

Krishna Kumar Saxena ◽

Emilio P. Calius ◽

Raj Das

Keyword(s):

3D Printing ◽

Impact Resistance ◽

Interesting Property ◽

Cellular Materials ◽

Strain Sensitivity ◽

Gradient Distribution ◽

Mechanical Metamaterials ◽

Potential Applications ◽

Protection Devices ◽

Impact Protection

The properties of cellular materials depend as much on their architecture as on their composition. Auxetic materials are a novel class of mechanical metamaterials which exhibit an interesting property of negative Poisson’s ratio by virtue of their architecture rather than composition. One of their most interesting aspects is their improved indentation resistance, impact resistance and fracture toughness. Thus, they have potential applications in wearable impact protection. The classical re-entrant structure has been a focus of research for many years because of its well established auxetic behaviour. However, the stiff re-entrant corners, buckling of struts, less strain sensitivity and limited cellular stiffness limit its applications in wearable impact protection devices. In this work, multi-material cellular designs are proposed which have the capability to fulfill the requirements for wearable impact protection devices. With the advancements in 3D printing, multi-material cellular designs can be realized in practice. Using Finite Elements approach, two-material and multi-material cellular designs are investigated. It was observed that introduction of material gradient/distribution in the cell provides a means to tailor auxetic behaviour, cellular stiffness and strain-sensitivity as per the specific requirement. The results will lead to a better understanding of tailoring auxeticity in cellular materials and will aid in the design of auxetic wearable impact protection devices which rely on auxeticity gradients and variable auxeticity as well.

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Experimental and Numerical Analysis of 3D Printed Polymer Tetra-Petal Auxetic Structures under Compression

Applied Sciences ◽

10.3390/app112110362 ◽

2021 ◽

Vol 11 (21) ◽

pp. 10362

Author(s):

Demetris Photiou ◽

Stelios Avraam ◽

Francesco Sillani ◽

Fabrizio Verga ◽

Olivier Jay ◽

...

Keyword(s):

Finite Element ◽

3D Printing ◽

Mechanical Response ◽

Mechanical Performance ◽

Poisson Ratio ◽

Impact Resistance ◽

Experimental Tests ◽

Polymer Materials ◽

Compression Tests ◽

Auxetic Structures

Auxetic structures possess a negative Poisson ratio (ν < 0) as a result of their geometrical configuration, which exhibits enhanced indentation resistance, fracture toughness, and impact resistance, as well as exceptional mechanical response advantages for applications in defense, biomedical, automotive, aerospace, sports, consumer goods, and personal protective equipment sectors. With the advent of additive manufacturing, it has become possible to produce complex shapes with auxetic properties, which could not have been possible with traditional manufacturing. Three-dimensional printing enables easy and precise control of the geometry and material composition of the creation of desirable shapes, providing the opportunity to explore different geometric aspects of auxetic structures with a variety of different materials. This study investigated the geometrical and material combinations that can be jointly tailored to optimize the auxetic effects of 2D and 3D complex structures by integrating design, modelling approaches, 3D printing, and mechanical testing. The simulation-driven design methodology allowed for the identification and creation of optimum auxetic prototype samples manufactured by 3D printing with different polymer materials. Compression tests were performed to characterize the auxetic behavior of the different system configurations. The experimental investigation demonstrated a Poisson’s ration reaching a value of ν = −0.6 for certain shape and material combinations, thus providing support for preliminary finite element studies on unit cells. Finally, based on the experimental tests, 3D finite element models with elastic material formulations were generated to replicate the mechanical performance of the auxetic structures by means of simulations. The findings showed a coherent deformation behavior with experimental measurements and image analysis.

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