scholarly journals Effect of infill density and pattern on the specific load capacity of FDM 3D-printed PLA multi-layer sandwich

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
József Dobos ◽  
Muammel M. Hanon ◽  
István Oldal
Keyword(s):  
Load Capacity ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Bending Test ◽  
Material Structure ◽  
Specific Load ◽  
3D Printed ◽  
Plastic Parts ◽  
The Given ◽  
Manufacturing Time

Abstract Three-dimensional (3D) printing settings allow the existence of differently filled sections together within a piece. That means the use of inhomogeneous internal material structure. Knowing the load capacity that 3D printed plastic parts can withstand leads to the reduction of the filling degree, thus the amount of the used material in certain places. This approach has two advantages during production: (i) less material use and (ii) reduced manufacturing time, both being cost-reducing factors. The present research aims to find the optimal proportions for fabricating a bending test piece with varying filling degrees. To achieve this goal, experimental tests were performed for obtaining tensile strength and modulus of elasticity using different pairs of infill density and pattern. This provided a basis for creating a working mechanical model based on accurate and realistic material properties. Hence, a series of virtual bending test experiments were conducted on a sandwich structure specimen employing Ansys Workbench software. By doing so, the optimal thickness (of the sandwich’s inner layer) with the highest specific load capacity for the given filling patterns and densities were determined. To the best of our knowledge, the current procedure of experiments and method of settings optimization were not discussed elsewhere.

scholarly journals On the Post-Processing of 3D-Printed ABS Parts

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1559
Author(s):  
Mohammad Reza Khosravani ◽  
Jonas Schüürmann ◽  
Filippo Berto ◽  
Tamara Reinicke
Keyword(s):  
Surface Treatment ◽  
Fused Deposition Modeling ◽  
Three Dimensional ◽  
Acrylonitrile Butadiene Styrene ◽  
Experimental Tests ◽  
Fracture Load ◽  
Post Processing ◽  
Fused Deposition ◽  
Dog Bone ◽  
3D Printed

Application of Additive Manufacturing (AM) has significantly increased in the past few years. AM also known as three-dimensional (3D) printing has been currently used in fabrication of prototypes and end-use products. Considering the new applications of additively manufactured components, it is necessary to study structural details of these parts. In the current study, influence of a post-processing on the mechanical properties of 3D-printed parts has been investigated. To this aim, Acrylonitrile Butadiene Styrene (ABS) material was used to produce test coupons based on the Fused Deposition Modeling (FDM) process. More in deep, a device was designed and fabricated to fix imperfection and provide smooth surfaces on the 3D-printed ABS specimens. Later, original and treated specimens were subjected to a series of tensile loads, three-point bending tests, and water absorption tests. The experimental tests indicated fracture load in untreated dog-bone shaped specimen was 2026.1 N which was decreased to 1951.7 N after surface treatment. Moreover, the performed surface treatment was lead and decrease in tensile strength from 29.37 MPa to 26.25 MPa. Comparison of the results confirmed effects of the surface modification on the fracture toughness of the examined semi-circular bending components. Moreover, a 3D laser microscope was used for visual investigation of the specimens. The documented results are beneficial for next designs and optimization of finishing processes.

scholarly journals Numerical Analysis of the Perforated Steel Sheets Under Uni-Axial Tensile Force

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 632 ◽  
Author(s):  
Ahmed M. Sayed
Keyword(s):  
Load Capacity ◽  
Tensile Force ◽  
Three Dimensional ◽  
Tensile Load ◽  
Experimental Tests ◽  
Strain Engineering ◽  
Uniaxial Tensile ◽  
Fe Model ◽  
Stress Strain ◽  
Steel Sheets

The perforated steel sheets have many uses, so they should be studied under the influence of the uniaxial tensile load. The presence of these holes in the steel sheets certainly affects the mechanical properties. This paper aims at studying the behavior of the stress-strain engineering relationships of the perforated steel sheets. To achieve this, the three-dimensional finite element (FE) model is mainly designed to investigate the effect of this condition. Experimental tests were carried out on solid specimens to be used in the test of model accuracy of the FE simulation. Simulation testing shows that the FE modeling revealed the ability to calculate the stress-strain engineering relationships of perforated steel sheets. It can be concluded that the effect of a perforated rhombus shape is greater than the others, and perforated square shape has no effect on the stress-strain engineering relationships. The efficiency of the perforated staggered or linearly distribution shapes with the actual net area on the applied loads has the opposite effect, as it reduces the load capacity for all types of perforated shapes. Despite the decrease in load capacity, it improves the properties of the steel sheets.

Experimental and Numerical Investigation of Fretting Wear at High Temperature for Aeronautical Alloys

2010 ◽  
Author(s):  
D. Botto ◽  
A. Campagna ◽  
M. Lavella ◽  
M. M. Gola
Keyword(s):  
Three Dimensional ◽  
Experimental Tests ◽  
Fretting Wear ◽  
Numerical Code ◽  
Dissipated Energy ◽  
Hysteresis Cycle ◽  
Set Up ◽  
Wear Law ◽  
Low Amplitude ◽  
The Given

Fretting wear is a complex phenomenon that occurs at component interfaces that undergo low amplitude oscillation under high contact pressure. The aim of this paper is to investigate the fretting behavior of contact interfaces both with experiments and numerical code. The hysteresis cycles have been measured through the experiment and, at the end of the test, the worn volume has been determined. A numerical code has been developed to predict worn volume. The three-dimensional elastic contact problem has been solved by using a semi-analytical half space model. The numerical code uses a wear law for which the worn volume is proportional to the dissipated energy during the hysteresis cycle. The wear coefficient has been iteratively determined by comparing the theoretical results with the experimental tests. The main results of this work is the set up of a wear model for the given geometry and materials.

Fast production of customized three-dimensional-printed hand splints

2020 ◽  
Vol 26 (1) ◽  
pp. 134-144 ◽  
Author(s):  
Diana Popescu ◽  
Aurelian Zapciu ◽  
Cristian Tarba ◽  
Dan Laptoiu
Keyword(s):  
3D Printing ◽  
Three Dimensional ◽  
Online Application ◽  
Content Type ◽  
3D Cad ◽  
Aesthetic Appearance ◽  
3D Printed ◽  
Manufacturing Time ◽  
Practical Implications

Purpose This paper aims to propose a new solution for producing customized three-dimensional (3D)-printed flat-shaped splints, which are then thermoformed to fit the patient’s hand. The splint design process is automated and is available to clinicians through an online application. Design/methodology/approach Patient anthropometric data measured by clinicians are associated with variables of parametric 3D splint models. Once these variables are input by clinicians in the online app, customized stereo lithography (STL) files for both splint and half mold, in the case of the bi-material splint, are automatically generated and become available for download. Bi-materials splints are produced by a hybrid manufacturing process involving 3D printing and overmolding. Findings This approach eliminates the need for 3D CAD-proficient clinicians, allows fast generation of customized splints, generates two-dimensional (2D) drawings of splints for verifying shape and dimensions before 3D printing and generates the STL files. Automation reduces splint design time and cost, while manufacturing time is diminished by 3D printing the splint in a flat position. Practical implications The app could be used in clinical practice. It meets the demands of mass customization using 3D printing in a field where individualization is mandatory. The solution is scalable – it can be extended to other splint designs or to other limbs. 3D-printed tailored splints can offer improved wearing comfort and aesthetic appearance, while maintaining hand immobilization, allowing visually controlled follow-up for edema and rapidly observing the need for revision if necessary. Originality/value An online application was developed for uploading patient measurements and downloading 2D drawings and STL files of customized splints. Different models of splints can be designed and included in the database as alternative variants. A method for producing bi-materials flat splints combining soft and rigid polymers represents another novelty of the research.

Three-Dimensional Modeling and Computational Analysis of the Human Cornea Considering Distributed Collagen Fibril Orientations

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
Anna Pandolfi ◽  
Gerhard A. Holzapfel
Keyword(s):  
Collagen Fibril ◽  
Mechanical Response ◽  
Corneal Thickness ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Von Mises Stress ◽  
Fibrillar Structure ◽  
Material Structure ◽  
Human Cornea ◽  
Refractive Power

Experimental tests on human corneas reveal distinguished reinforcing collagen lamellar structures that may be well described by a structural constitutive model considering distributed collagen fibril orientations along the superior-inferior and the nasal-temporal meridians. A proper interplay between the material structure and the geometry guarantees the refractive function and defines the refractive properties of the cornea. We propose a three-dimensional computational model for the human cornea that is able to provide the refractive power by analyzing the structural mechanical response with the nonlinear regime and the effect the intraocular pressure has. For an assigned unloaded geometry we show how the distribution of the von Mises stress at the top surface of the cornea and through the corneal thickness and the refractive power depend on the material properties and the fibril dispersion. We conclude that a model for the human cornea must not disregard the peculiar collagen fibrillar structure, which equips the cornea with the unique biophysical, mechanical, and optical properties.

scholarly journals Finite element model of bamboo culm (Phyllostachys sp.) and its comparison to two experimental tests

2010 ◽  
Vol 58 (1) ◽  
pp. 153-160
Author(s):  
Václav Sebera ◽  
Jan Tippner ◽  
Petr Horáček ◽  
Aleš Dejmal ◽  
Martin Beníček
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Material Model ◽  
Element Model ◽  
Parametric Models ◽  
Bending Test ◽  
Bamboo Culm ◽  
Culm Wall

The main goal of the work was to build up a general parametric finite-element model of a bamboo culm in ANSYS computational system. Subsequently the model was compared to a experimental measurements of chosen mechanical properties – three point bending test and brasil test. A pa­ra­me­ter being compared was a force, which is necessary to exert to deform a sample on given strain. In this work two parametric models were created. First one is including dividing barrier – diaphragm. A mesh of the culm wall is mapped and is divided into three layers with different orthotropic material models in cylindrical coordinate system with respect to the culm axis. By contrast the barrier – diaphragm – is represented by free mesh with isotropic material model. Both FE models are fully parametric and three-dimensional. Hence they are very well utilizable for both further research of the bamboo itself and constructions from it.

Passive Contra-Magnetized Parallel-Airgap Serial Flux Magnetic Bearings

2010 ◽  
Vol 224 (11) ◽  
pp. 2515-2524
Author(s):  
K Kalita ◽  
W K S Khoo ◽  
S D Garvey ◽  
R J Hill-Cottingham ◽  
D Rodger ◽  
...  
Keyword(s):  
Load Capacity ◽  
Three Dimensional ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Two Dimensional ◽  
Specific Load ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Automatic Mesh

Conventional magnetic bearings accomplish a specific load capacity, defined as the ratio of maximum sustainable weight to the total self-weight, of up to 35:1. In this paper, the authors introduce a class of passive magnetic bearings that comprise a large number of parallel airgaps and discs and can deliver specific load capacities substantially higher than 35:1. Two-dimensional planar, two-dimensional axi-symmetric, and three-dimensional finite-element analysis (FEA) have been undertaken to predict the force capability of the bearings. An unoptimized prototype passive magnetic bearing is constructed to demonstrate the concept and its force-carrying capacity. The experimental results are then compared with those obtained from the FEA. Further optimization of the bearings is done across the whole design space comprising tens of thousands of models using an automatic mesh generator in conjunction with solving the FE models in nested loops.

A Customer-to-Manufacturer Design Model for Custom Compression Casts

2019 ◽  
Author(s):  
Yunbo Zhang ◽  
Tsz-Ho Kwok
Keyword(s):  
Optimization Problem ◽  
Three Dimensional ◽  
Human Model ◽  
Solid Model ◽  
3D Printer ◽  
Computational Framework ◽  
Mesh Surface ◽  
Interactive Tools ◽  
3D Printed ◽  
The Given

Abstract This paper presents a computational framework for designing and optimizing custom compression casts/braces. Different from the conventional cast/brace design, our framework generates custom casts/braces with fitness, lightweight, and good ventilation. The computational pipeline is an end-to-end solution, directly from customer to the manufacturer, which starts from a 3D scanned human model represented by mesh and ends with the 3D printed cast/brace. Our interactive tools allows users to define and edit the 3D curves on the mesh surface, and trim the mesh surface to form the cast/brace shape using the curves. These tools are efficient and simple to use, and also they enable designing the custom casts/braces fitting to the given human body. In order to reduce the weight and improve the ventilation, we adopt the topology optimization (TO) method to optimize the cast/brace design. We extend the existing three-dimensional (3D) TO method to the mesh surface by simplifying the optimization problem to a 2D problem. Therefore, the efficiency of the TO computation is improved significantly. After the optimized cast/brace design is obtained on the mesh surface, a solid model is generated by our design interface and then sent to a 3D printer for fabrication. Simulation results show that our method can better re-disturb the stresses compared with the conventional 3D TO.

scholarly journals Fracture Resistance Analysis of 3D-Printed Polymers

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 302 ◽  
Author(s):  
Ali Zolfagharian ◽  
Mohammad Reza Khosravani ◽  
Akif Kaynak
Keyword(s):  
Fused Deposition Modeling ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Equivalent Material ◽  
J Integral ◽  
Unstable Crack ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
3D Printed ◽  
Vital Component

Three-dimensional (3D)-printed parts are an essential subcategory of additive manufacturing with the recent proliferation of research in this area. However, 3D-printed parts fabricated by different techniques differ in terms of microstructure and material properties. Catastrophic failures often occur due to unstable crack propagations and therefore a study of fracture behavior of 3D-printed components is a vital component of engineering design. In this paper, experimental tests and numerical studies of fracture modes are presented. A series of experiments were performed on 3D-printed nylon samples made by fused deposition modeling (FDM) and multi-jet fusion (MJF) to determine the load-carrying capacity of U-notched plates fabricated by two different 3D printing techniques. The equivalent material concept (EMC) was used in conjunction with the J-integral failure criterion to investigate the failure of the notched samples. Numerical simulations indicated that when EMC was combined with the J-integral criterion the experimental results could be predicted successfully for the 3D-printed polymer samples.

Use of Three-dimensional Printing in the Development of Optimal Cardiac CT Scanning Protocols

2020 ◽  
Vol 16 (8) ◽  
pp. 967-977
Author(s):  
Zhonghua Sun
Keyword(s):  
Cardiovascular Disease ◽  
Cardiac Computed Tomography ◽  
Three Dimensional ◽  
Ct Scanning ◽  
Aortic Diseases ◽  
Clinical Value ◽  
Three Dimensional Printing ◽  
Doctor Patient Communication ◽  
Medical Education And Training ◽  
3D Printed

Three-dimensional (3D) printing is increasingly used in medical applications with most of the studies focusing on its applications in medical education and training, pre-surgical planning and simulation, and doctor-patient communication. An emerging area of utilising 3D printed models lies in the development of cardiac computed tomography (CT) protocols for visualisation and detection of cardiovascular disease. Specifically, 3D printed heart and cardiovascular models have shown potential value in the evaluation of coronary plaques and coronary stents, aortic diseases and detection of pulmonary embolism. This review article provides an overview of the clinical value of 3D printed models in these areas with regard to the development of optimal CT scanning protocols for both diagnostic evaluation of cardiovascular disease and reduction of radiation dose. The expected outcomes are to encourage further research towards this direction.

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