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Article
Publication date: 20 October 2014

Jaroslaw Kotlinski

– This paper aims to relate to the study of mechanical properties of materials used in rapid prototyping (RP).

2583

Abstract

Purpose

This paper aims to relate to the study of mechanical properties of materials used in rapid prototyping (RP).

Design/methodology/approach

Comparison of mechanical properties of commercial RP materials. The study of the literature was the essential source of obtaining the results necessary to complete the evaluations and to determine the property ranges.

Findings

Specifications of mechanical properties collected in one paper about mechanical properties and anisotropy enable to define limitations for prototype properties.

Research limitations/implications

The study is limited to accessible data concerning materials from manufacturers’ offers.

Practical implications

The study is particularly useful in the RP methods application.

Originality/value

The obtained study of mechanical properties makes a quick analysis possible. This article also includes the guideline for design engineers, which determines RP method suitability to create functional prototypes of the machines. Mechanical properties of materials have been adopted as a criterion.

Details

Rapid Prototyping Journal, vol. 20 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 14 September 2011

Jacob Azoulay

The high Tc superconductors (HTS) are characterized by magneto electric anisotropy due to their pronounced material anisotropy. It is expected to observe also some…

Abstract

The high Tc superconductors (HTS) are characterized by magneto electric anisotropy due to their pronounced material anisotropy. It is expected to observe also some mechanical anisotropy. The mechanical properties of c-axis oriented and <110>-axis oriented films are reported. The two differently orientated films comprise an ideal case for comparative studies on mechanical anisotropy. Scanning electron microscope (SEM) and atomic force microscope (AFM) were used to study the films' surface. Nanoindentation and nanoscratch techniques were used to test the elastic behaviors and hardness of the films. Mechanical anisotropies was found, analyzed and discussed.

Details

World Journal of Engineering, vol. 8 no. 3
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 17 August 2021

Mingkang Zhang, Yongqiang Yang, Meizhen Xu, Jie Chen and Di Wang

The purpose of this study is focused on the mechanical properties of multi-materials porous structures manufactured by selective laser melting (SLM).

Abstract

Purpose

The purpose of this study is focused on the mechanical properties of multi-materials porous structures manufactured by selective laser melting (SLM).

Design/methodology/approach

The Diamond structure was designed by the triply periodic minimal surface function in MATLAB, and multi-materials porous structures were manufactured by SLM. Compression tests were applied to analyze the anisotropy of mechanical properties of multi-materials porous structures.

Findings

Compression results show that the multi-materials porous structure has a strong anisotropy behavior. When the compression force direction is parallel to the material arrangement, multi-materials porous structure was compressed in a layer-by-layer way, which is the traditional deformation of the gradient structure. However, when the compression force direction is perpendicular to the material arrangement, the compression curves show a near-periodic saw-tooth waveform characteristic, and this kind of structure was compressed consistently. It is demonstrated that the combination with high strength brittle material and low strength plastic material improves compression mode, and plastic material plays a role in buffering fracture.

Originality/value

This research provides a new method for the design and manufacturing of multi-materials porous structures and an approach to change the compression behavior of the porous structure.

Details

Rapid Prototyping Journal, vol. 27 no. 9
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 18 August 2021

Nadim S. Hmeidat, Bailey Brown, Xiu Jia, Natasha Vermaak and Brett Compton

Mechanical anisotropy associated with material extrusion additive manufacturing (AM) complicates the design of complex structures. This study aims to focus on…

Abstract

Purpose

Mechanical anisotropy associated with material extrusion additive manufacturing (AM) complicates the design of complex structures. This study aims to focus on investigating the effects of design choices offered by material extrusion AM – namely, the choice of infill pattern – on the structural performance and optimality of a given optimized topology. Elucidation of these effects provides evidence that using design tools that incorporate anisotropic behavior is necessary for designing truly optimal structures for manufacturing via AM.

Design/methodology/approach

A benchmark topology optimization (TO) problem was solved for compliance minimization of a thick beam in three-point bending and the resulting geometry was printed using fused filament fabrication. The optimized geometry was printed using a variety of infill patterns and the strength, stiffness and failure behavior were analyzed and compared. The bending tests were accompanied by corresponding elastic finite element analyzes (FEA) in ABAQUS. The FEA used the material properties obtained during tensile and shear testing to define orthotropic composite plies and simulate individual printed layers in the physical specimens.

Findings

Experiments showed that stiffness varied by as much as 22% and failure load varied by as much as 426% between structures printed with different infill patterns. The observed failure modes were also highly dependent on infill patterns with failure propagating along with printed interfaces for all infill patterns that were consistent between layers. Elastic FEA using orthotropic composite plies was found to accurately predict the stiffness of printed structures, but a simple maximum stress failure criterion was not sufficient to predict strength. Despite this, FE stress contours proved beneficial in identifying the locations of failure in printed structures.

Originality/value

This study quantifies the effects of infill patterns in printed structures using a classic TO geometry. The results presented to establish a benchmark that can be used to guide the development of emerging manufacturing-oriented TO protocols that incorporate directionally-dependent, process-specific material properties.

Details

Rapid Prototyping Journal, vol. 27 no. 8
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 1 March 2000

J.S. Ullett, J.W. Schultz and R.P. Chartoff

The build characteristics of two liquid crystal (LC) reactive monomers were studied using a table‐top stereolithography apparatus (TTSLA). LC materials contain stiff…

1201

Abstract

The build characteristics of two liquid crystal (LC) reactive monomers were studied using a table‐top stereolithography apparatus (TTSLA). LC materials contain stiff, rod‐like mesogenic segments in their molecules, which can be aligned causing an anisotropy in properties. When cured in the aligned state the anisotropic structure is “locked in” resulting in materials with anisotropic physical and mechanical properties. By varying the alignment of layers, properties such as thermal expansion coefficient can be optimized. High heat distortion (or glass transition) temperatures are possible depending on the monomer chemical structure. Working curves for the LC resins were developed under various conditions. A permanent magnet placed outside the TTSLA vat was used to uniformly align the monomer in the nematic state. Photo‐initiator type and content; alignment of the nematic phase; and operating conditions affected the working curve parameters. Glass transition temperatures of post‐cured parts ranged from 75 to 1488C depending on the resin and processing conditions. Mechanical analysis data revealed a factor of two difference between glassy moduli measured in the molecular alignment versus the transverse alignment directions. Based on these initial studies, more advanced resins with higher glass transitions are being developed at the University of Dayton.

Details

Rapid Prototyping Journal, vol. 6 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 5 October 2020

Mozhgan Sayanjali, Amir Masood Rezadoust and Foroud Abbassi Sourki

This paper aims to focus on the development of the three-dimensional (3D) printing filaments based on acrylonitrile butadiene styrene (ABS) copolymer and…

Abstract

Purpose

This paper aims to focus on the development of the three-dimensional (3D) printing filaments based on acrylonitrile butadiene styrene (ABS) copolymer and styrene-ethylene/butylene-styrene (SEBS) block copolymer, with tailored viscoelastic properties and controlled flow during the 3D printing process.

Design/methodology/approach

In this investigation, ABS was blended with various amounts of SEBS via a melt mixing process. Then the ABS/SEBS filaments were prepared by a single-screw extruder and printed by the FDM method. The rheological properties were determined using an MCR 501 from Anton-Paar. The melt flow behavior of ABS/SEBS filaments was determined. The morphology of the filaments was studied by scanning electron microscope and the mechanical (tensile and impact) properties, surface roughness and void content of printed samples were investigated.

Findings

The rheological results can accurately interpret what drives the morphology and mechanical properties’ changes in the blends. The impact strength, toughness, elongation-at-break and anisotropy in mechanical properties of ABS samples were improved concurrently by adding 40 Wt.% of SEBS. The optimal tensile properties of blend containing 40 Wt.% SEBS samples were obtained at −45°/+45° raster angle, 0.05 mm layer thickness and XYZ build orientation. Optimized samples showed an 890% increase in elongation compared to neat ABS. Also, the impact strength of ABS samples showed a 60% improvement by adding 40 Wt.% SEBS.

Originality/value

The paper simultaneously evaluates the effects of material composition and 3D printing parameters (layer thickness, raster angle and build orientation) on the rheology, morphology, mechanical properties and surface roughness. Also, a mechanical properties comparison between printed samples and their compression-molded counterpart was conducted.

Details

Rapid Prototyping Journal, vol. 26 no. 10
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 20 June 2017

Jason T. Cantrell, Sean Rohde, David Damiani, Rishi Gurnani, Luke DiSandro, Josh Anton, Andie Young, Alex Jerez, Douglas Steinbach, Calvin Kroese and Peter G. Ifju

This paper aims to present the methodology and results of the experimental characterization of three-dimensional (3D) printed acrylonitrile butadiene styrene (ABS) and…

2953

Abstract

Purpose

This paper aims to present the methodology and results of the experimental characterization of three-dimensional (3D) printed acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) parts utilizing digital image correlation (DIC).

Design/methodology/approach

Tensile and shear characterizations of ABS and PC 3D-printed parts were performed to determine the extent of anisotropy present in 3D-printed materials. Specimens were printed with varying raster ([+45/−45], [+30/−60], [+15/−75] and [0/90]) and build orientations (flat, on-edge and up-right) to determine the directional properties of the materials. Tensile and Iosipescu shear specimens were printed and loaded in a universal testing machine utilizing two-dimensional (2D) DIC to measure strain. The Poisson’s ratio, Young’s modulus, offset yield strength, tensile strength at yield, elongation at break, tensile stress at break and strain energy density were gathered for each tensile orientation combination. Shear modulus, offset yield strength and shear strength at yield values were collected for each shear combination.

Findings

Results indicated that raster and build orientations had negligible effects on the Young’s modulus or Poisson’s ratio in ABS tensile specimens. Shear modulus and shear offset yield strength varied by up to 33 per cent in ABS specimens, signifying that tensile properties are not indicative of shear properties. Raster orientation in the flat build samples reveals anisotropic behavior in PC specimens as the moduli and strengths varied by up to 20 per cent. Similar variations were observed in shear for PC. Changing the build orientation of PC specimens appeared to reveal a similar magnitude of variation in material properties.

Originality/value

This article tests tensile and shear specimens utilizing DIC, which has not been employed previously with 3D-printed specimens. The extensive shear testing conducted in this paper has not been previously attempted, and the results indicate the need for shear testing to understand the 3D-printed material behavior fully.

Details

Rapid Prototyping Journal, vol. 23 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 16 March 2015

David Roberson, Corey M Shemelya, Eric MacDonald and Ryan Wicker

The purpose of this paper is to demonstrate the strategy for increasing the applicability of material extrusion additive manufacturing (AM) technologies, based on fused…

2018

Abstract

Purpose

The purpose of this paper is to demonstrate the strategy for increasing the applicability of material extrusion additive manufacturing (AM) technologies, based on fused deposition modeling (FDM), through the development of materials with targeted physical properties. Here, the authors demonstrate materials specifically developed for the manufacture of electromechanical and electromagnetic applications, the use of FDM-type processes in austere environments and the application of material extrusion AM.

Design/methodology/approach

Using a twin screw polymeric extrusion process, novel polymer matrix composites and blends were created where the base material was a material commonly used in FDM-type processes, namely, acrylonitrile butadiene styrene (ABS) or polycarbonate (PC).

Findings

The work presented here demonstrates that, through targeted materials development, the applicability of AM platforms based on FDM technology can be increased. Here, the authors demonstrate that that the physical properties of ABS and PC can be manipulated to be used in several applications such as electromagnetic and X-ray shielding. Other instances of the development of new materials for FDM led to mitigation of problems associated with the process such as surface finish and mechanical property anisotropy based on build orientation.

Originality/value

This paper is an overview of a research effort dedicated to increasing the amount of material systems available to material extrusion AM. Here materials development is shown to not only increase the number of suitable applications for FDM-type processes, but to be a pathway toward solving inherent problems associated with FDM such as surface finish and build orientation-caused mechanical property anisotropy.

Details

Rapid Prototyping Journal, vol. 21 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 1 December 2004

Jaroslav Mackerle

Sheet metal forming is a process of shaping thin sheets of metal by applying pressure through male or female dies or both. In most of used sheet‐formating processes the…

4454

Abstract

Sheet metal forming is a process of shaping thin sheets of metal by applying pressure through male or female dies or both. In most of used sheet‐formating processes the metal is subjected to primarily tensile or compressive stresses or both. During the last three decades considerable advances have been made in the applications of numerical techniques, especially the finite element methods, to analyze physical phenomena in the field of structural, solid and fluid mechanics as well as to simulate various processes in engineering. These methods are useful because one can use them to find out facts or study the processes in a way that no other tool can accomplish. Finite element methods applied to sheet metal forming are the subjects of this paper. The reason for writing this bibliography is to save time for readers looking for information dealing with sheet metal forming, not having an access to large databases or willingness to spend own time with uncertain information retrieval. This paper is organized into two parts. In the first one, each topic is handled and current trends in the application of finite element techniques are briefly mentioned. The second part, an Appendix, lists papers published in the open literature. More than 900 references to papers, conference proceedings and theses/dissertations dealing with subjects that were published in 1995‐2003 are listed.

Details

Engineering Computations, vol. 21 no. 8
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 10 June 2014

Javier Munguia and Kenny Dalgarno

The purpose of this paper was twofold: first, to determine if rotating bending could be used as an effective way of determining the fatigue behaviour of laser-sintered…

Abstract

Purpose

The purpose of this paper was twofold: first, to determine if rotating bending could be used as an effective way of determining the fatigue behaviour of laser-sintered nylon, and second, to examine whether the fatigue behaviour of laser-sintered PA12 showed any significant anisotropy.

Design/methodology/approach

Specimens were measured to obtain dimensional accuracy, density and surface roughness levels. Then, uniaxial tensile and rotating-bending fatigue tests were performed. A purpose-built test-jig has been used to subject hourglass-shaped specimens to reversed bending at two frequencies: 50 and 30 Hz. Additionally, thermal and microstructural analyses were performed to understand the underlying mechanisms of failure.

Findings

The experiments suggest PA12 specimens will fail in fatigue following the conventional fatigue mechanisms observed in previous research with ductile polymers. Although high-frequency loading caused a heat build-up in the specimen, temperatures stabilised between 20 and 30°C, suggesting that rotating-bending fatigue at frequencies of up to 50 Hz is a valid way of determining the fatigue behaviour of laser-sintered PA12 specimens. Stresses below 20 MPa led to fatigue lives above 1 million cycles. Some anisotropic behaviour was observed in the fatigue test results, with specimens made orientated with the Z axis showing the lowest fatigue lives on average, but an endurance limit of approximately 15 MPa seems to be common for all specimens regardless of their build orientation.

Practical implications

The observed endurance limit of 15 MPa did not depend significantly on the orientation at which a part was built – meaning that it may be possible to guarantee a service life for a part which does not depend on part orientation within a build. Clearly, good-quality control will also be required to ensure performance, but this has important implications for the design of laser-sintered PA12 parts for realistic service conditions.

Originality/value

To our knowledge, this is the first paper to present rotating-bending fatigue data for laser-sintered PA12 parts, and the first to identify an endurance limit which is independent of part orientation.

Details

Rapid Prototyping Journal, vol. 20 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

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