scholarly journals The Development of a Gracilis and Quadriceps Tendons Calibration Device for Uniaxial Tensile Tests

Machines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 364
Author(s):  
Ivan Grgić ◽  
Mirko Karakašić ◽  
Željko Ivandić ◽  
Tanja Jurčević Jurčević Lulić
Keyword(s):  
Fused Deposition Modeling ◽  
Soft Tissues ◽  
Complex Geometry ◽  
Tensile Tests ◽  
Gauge Length ◽  
Uniaxial Tensile ◽  
Specimen Preparation ◽  
Tissue Properties ◽  
Fused Deposition ◽  
Calibration Device

To determine the biomechanical properties of the distal tendon of the gracilis muscle and the upper third of the quadriceps femoris muscle used for reconstruction of the medial patellofemoral ligament (MPFL), it is necessary to develop a calibration device for specimen preparation for uniaxial tensile tests. The need to develop this device also stems from the fact that there is currently no suitable regulatory or accurate protocol by which soft tissues such as tendons should be tested. In recent studies, various methods have been used to prepare test specimens, such as the use of different ratios of gauge lengths, different gripping techniques, etc., with the aim of obtaining measurable and comparable biomechanical tissue properties. Since tendons, as anisotropic materials, have viscoelastic properties, the guideline for manufacturing calibrator devices was the ISO 527-1:1993 standard, used for testing polymers, since they also have viscoelastic behaviour. The functionality of a calibrator device was investigated by preparing gracilis and quadriceps tendon samples. Fused deposition modeling (FDM) technology was used for the manufacturing of parts with complex geometry. The proposed calibrator could operate in two positions, horizontal and vertical. The maximum gauge length to be achieved was 60 mm, with the maximum tendon length of 120 mm. The average preparation time was 3 min per tendon. It was experimentally proven that it is possible to use a calibrator to prepare tendons for tensile tests. This research can help in the further development of soft tissue testing devices and also in the establishment of standards and exact protocols for their testing.

scholarly journals Optimization of Manufacturing Parameters and Tensile Specimen Geometry for Fused Deposition Modeling (FDM) 3D-Printed PETG

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2556
Author(s):  
Arda Özen ◽  
Dietmar Auhl ◽  
Christina Völlmecke ◽  
Josef Kiendl ◽  
Bilen Emek Abali
Keyword(s):  
Mechanical Properties ◽  
Fused Deposition Modeling ◽  
Tensile Tests ◽  
Tensile Specimen ◽  
Careful Examination ◽  
Uniaxial Tensile ◽  
Fused Deposition ◽  
Design Flexibility ◽  
Deposition Modeling ◽  
3D Printed

Additive manufacturing provides high design flexibility, but its use is restricted by limited mechanical properties compared to conventional production methods. As technology is still emerging, several approaches exist in the literature for quantifying and improving mechanical properties. In this study, we investigate characterizing materials’ response of additive manufactured structures, specifically by fused deposition modeling (FDM). A comparative analysis is achieved for four different tensile test specimens for polymers based on ASTM D3039 and ISO 527-2 standards. Comparison of specimen geometries is studied with the aid of computations based on the Finite Element Method (FEM). Uniaxial tensile tests are carried out, after a careful examination of different slicing approaches for 3D printing. We emphasize the effects of the chosen slicer parameters on the position of failures in the specimens and propose a simple formalism for measuring effective mechanical properties of 3D-printed structures.

Characterization of PLA/TPU composite filaments manufactured for 3D printing with FDM

2021 ◽  
pp. 089270572110625
Author(s):  
Ajay Jayswal ◽  
Sabit Adanur
Keyword(s):  
3D Printing ◽  
Fused Deposition Modeling ◽  
Thermoplastic Polyurethane ◽  
Tensile Tests ◽  
Optical Microscope ◽  
Mechanical Analysis ◽  
Uniaxial Tensile ◽  
Scanning Calorimetry ◽  
Fused Deposition ◽  
3D Printed

Polylactic acid (PLA) and thermoplastic polyurethane (TPU) were mixed in different proportions and extruded through twin-screw and single-screw extruders to obtain composite filaments to be used for 3D printing with fused deposition modeling (FDM) method. The properties of the filaments were characterized using uniaxial tensile tests, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), rheology, polarized optical microscope (POM), and scanning electron microscope (SEM). 3D printed samples from composite filaments were tested using dynamic mechanical analysis (DMA). It was found that the tensile strength and modulus of the filaments decrease while elongation at break increases with the increasing TPU content in the composite. The analysis also showed a partial miscibility of the polymer constituents in the solution of composite filaments. Finally, a flexible structure, plain weave fabric, was designed and 3D printed using the composite filaments developed which proved that the filaments are well suited for 3D printing.

scholarly journals 3D Printed Clamps for In Vitro Tensile Tests of Human Gracilis and the Superficial Third of Quadriceps Tendons

2021 ◽  
Vol 11 (6) ◽  
pp. 2563
Author(s):  
Ivan Grgić ◽  
Vjekoslav Wertheimer ◽  
Mirko Karakašić ◽  
Željko Ivandić
Keyword(s):  
3D Printing ◽  
Fused Deposition Modeling ◽  
Tensile Tests ◽  
Biomechanical Properties ◽  
Testing Procedure ◽  
Laboratory Equipment ◽  
Fused Deposition ◽  
Custom Made ◽  
3D Printed

Recent soft tissue studies have reported issues that occur during experimentation, such as the tissue slipping and rupturing during tensile loads, the lack of standard testing procedure and equipment, the necessity for existing laboratory equipment adaptation, etc. To overcome such issues and fulfil the need for the determination of the biomechanical properties of the human gracilis and the superficial third of the quadriceps tendons, 3D printed clamps with metric thread profile-based geometry were developed. The clamps’ geometry consists of a truncated pyramid pattern, which prevents the tendons from slipping and rupturing. The use of the thread application in the design of the clamp could be used in standard clamping development procedures, unlike in previously custom-made clamps. Fused deposition modeling (FDM) was used as a 3D printing technique, together with polylactic acid (PLA), which was used as a material for clamp printing. The design was confirmed and the experiments were conducted by using porcine and human tendons. The findings justify the usage of 3D printing technology for parts manufacturing in the case of tissue testing and establish independence from the existing machine clamp system, since it was possible to print clamps for each prepared specimen and thus reduce the time for experiment setup.

Systematic Experimental Investigation of Dielectric Electroactive Polymers Using a Custom-Built Uniaxial Tensile Test Rig

2015 ◽  
Author(s):  
Micah Hodgins ◽  
Alexander York ◽  
Stefan Seelecke
Keyword(s):  
Pure Shear ◽  
Tensile Force ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Specimen Preparation ◽  
Testing Device ◽  
Test Results ◽  
Test Rig ◽  
Geometry Test

This work presents the design, fabrication and testing of a comprehensive DEAP test station. The tester is designed to perform tensile tests of planar DEAPs while measuring quantities such as tensile force, stretch, film thickness and voltage/current. The work details the specimen preparation and how the specimen is placed in the clamps. While the assembly process is performed by hand features were built-in to the design of the specimen frame and clamps to enable reliable placement and specimen geometry. Test results of the pure-shear specimen demonstrated good performance of the testing device. Although the electrode surface was rough the thickness stretch was evident during the stretching/actuation of the DEAP actuator.

Inverse Mechanical Characterization of Tissue Engineered Heart Valves

2008 ◽  
Author(s):  
Martijn A. J. Cox ◽  
Jeroen Kortsmit ◽  
Niels J. B. Driessen ◽  
Carlijn V. C. Bouten ◽  
Frank P. T. Baaijens
Keyword(s):  
Heart Valves ◽  
Soft Tissues ◽  
Mechanical Characterization ◽  
Tensile Tests ◽  
Material Behavior ◽  
Uniaxial Tensile ◽  
Mechanical Conditioning ◽  
Indentation Tests ◽  
Tissue Engineered Heart Valves

Over the last few years, research interest in tissue engineering as an alternative for current treatment and replacement strategies for cardiovascular and heart valve diseases has significantly increased. In vitro mechanical conditioning is an essential tool for engineering strong implantable tissues [1]. Detailed knowledge of the mechanical properties of the native tissue as well as the properties of the developing engineered constructs is vital for a better understanding and control of the mechanical conditioning process. The nonlinear and anisotropic behavior of soft tissues puts high demands on their mechanical characterization. Current standards in mechanical testing of soft tissues include (multiaxial) tensile testing and indentation tests. Uniaxial tensile tests do not provide sufficient information for characterizing the full anisotropic material behavior, while biaxial tensile tests are difficult to perform, and boundary effects limit the test region to a small central portion of the tissue. In addition, characterization of the local tissue properties from a tensile test is non-trivial. Indentation tests may be used to overcome some of these limitations. Indentation tests are easy to perform and when indenter size is small relative to the tissue dimensions, local characterization is possible. We have demonstrated that by recording deformation gradients and indentation force during a spherical indentation test the anisotropic mechanical behavior of engineered cardiovascular constructs can be characterized [2]. In the current study this combined numerical-experimental approach is used on Tissue Engineered Heart Valves (TEHV).

scholarly journals Enhancing the Joining Properties of Biodegradable PLA from Fused Deposition Modeling by Infrared Laser Irradiation

2020 ◽  
Author(s):  
J.M. Vazquez-Martinez ◽  
D. Piñero ◽  
J. Salguero ◽  
M. Batista
Keyword(s):  
Additive Manufacturing ◽  
Laser Beam ◽  
Fused Deposition Modeling ◽  
Tensile Tests ◽  
Infrared Laser ◽  
Single Step ◽  
Step Method ◽  
Modeling Technology ◽  
Fused Deposition ◽  
Welding Processes

The development of high complexity geometry parts is one of the main goals of the additive manufacturing technology. However, the failure of printed structures and the joining of different parts to create complex assemblies represents a real challenge in the research of efficient and sustainability techniques for the permanent assembly of polymers. Laser welding processes have been used as a single step method to join metals until years ago. Nowadays, the growing trend in the use of thermoplastics for additive manufacturing has led to the need to adapt this technique to materials with a very specific nature and more sensitive to thermal effects. Also, the possibility of transmitting the laser beam through transparent polymer layers allows to focus the energy supply on internal sections of the assembled components. In this research, an infrared laser marking system was used to join two different samples of polylactic acid manufactured by fused deposited modeling technology. In order to increase the effectiveness of the bonding process, a transparent and a dark sample have been used as assembly material, focusing the laser beam on the interface area of the two parts. By means of tensile tests, dimensional measurement and the use of optical microscopy techniques, a basis was established that links the supplied energy by laser to the joining performance.

scholarly journals Measurement and Analysis of Heterogeneous Strain Fields in Uniaxial Tensile Tests for Boron Steel Under Hot Stamping Conditions

2020 ◽  
Vol 60 (9) ◽  
pp. 1289-1300
Author(s):  
R. Zhang ◽  
Z. Shao ◽  
J. Lin ◽  
T. A. Dean
Keyword(s):  
Temperature Gradient ◽  
Hot Stamping ◽  
Tensile Tests ◽  
Gauge Length ◽  
Image Correlation ◽  
Effect Of Temperature ◽  
Uniaxial Tensile ◽  
Boron Steel ◽  
Strain Fields ◽  
Dog Bone

Abstract Background A significant amount of uniaxial tensile tests has been carried out using Gleeble systems to investigate the viscoplastic deformation of boron steel (22MnB5) under hot stamping conditions. However, due to heat loss through the end clamps, a temperature gradient in the reduced parallel section of dog-bone shaped specimens is inevitable. Objective In the work reported in this paper, the effect of temperature gradient on measured outcomes is examined. Methods Uniaxial tensile tests on 1.5 mm thick boron steel specimens are carried out, under hot stamping conditions and strain fields are quantified using the digital image correlation (DIC) technique. The effect of gauge length on the properties of boron steel, as calculated from observed test results, is determined. Results Compared with the test at room temperature, a bell-shaped strain distribution occurs within the gauge length even before the appearance of the maximum load. Also, average strain within the gauge length, especially in the later stages, changes with gauge length within the investigated range, and thus, different engineering stress-strain curves and fracture strains are determined. In addition, normalized strain rate is significantly dependent on gauge length, which results in over 16% difference among the computed flow stresses by using a unified constitutive model. Conclusions The characterized properties of the material are dependent on gauge length and thus, a testing standard for measuring thermal-mechanical data of materials by using a Gleeble need to be defined.

scholarly journals Evaluation of the Joining Response of Biodegradable Polylactic Acid (PLA) from Fused Deposition Modeling by Infrared Laser Irradiation

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2479
Author(s):  
J. M. Vazquez-Martinez ◽  
D. Piñero ◽  
J. Salguero ◽  
M. Batista
Keyword(s):  
Additive Manufacturing ◽  
Laser Beam ◽  
Polylactic Acid ◽  
Fused Deposition Modeling ◽  
Tensile Tests ◽  
Infrared Laser ◽  
Single Step ◽  
Step Method ◽  
Fused Deposition ◽  
Welding Processes

The development of high-complexity geometry parts is one of the main goals of additive manufacturing technology. However, the failure of printed structures and the joining of different parts to create complex assemblies represents a real challenge in the research of efficient and sustainability techniques for the permanent assembly of polymers. Laser welding processes have been used as a single-step method to join metals for years. Nowadays, the growing trend in the use of thermoplastics for additive manufacturing has led to the need to adapt this technique to materials with a very specific nature and which are more sensitive to thermal effects. In addition, the possibility of transmitting the laser beam through transparent polymer layers allows to us focus the energy supply on internal sections of the assembled components. In this research, an infrared laser marking system was used to join two different samples of polylactic acid manufactured by fused deposited modeling technology. In order to increase the effectiveness of the bonding process, a transparent and a dark sample have been used as assembly material, focusing the laser beam on the interface area of the two parts. By means of tensile tests, dimensional measurement and the use of optical microscopy techniques, a basis was established that links the supplied energy by laser to the joining performance.

Systematic approach for the characterization of additive manufactured and injection molded short carbon fiber-reinforced polymers under tensile loading

2020 ◽  
Vol 62 (6) ◽  
pp. 561-567
Author(s):  
Patrick Striemann ◽  
Daniel Huelsbusch ◽  
Selim Mrzljak ◽  
Michael Niedermeier ◽  
Frank Walther
Keyword(s):  
Fused Deposition Modeling ◽  
Tensile Loading ◽  
Tensile Tests ◽  
Design Guidelines ◽  
Fiber Reinforced Polymers ◽  
Void Content ◽  
Micro Computed Tomography ◽  
Fused Filament Fabrication ◽  
Fused Deposition ◽  
Induced Defects

Abstract Material extrusion-based additive manufacturing techniques such as fused deposition modeling or fused filament fabrication are developing from prototyping applications to serial components. The aim of this study is to properly characterize an additively manufactured polymer with the corresponding process-induced defects. To this effect, varied manufacturing orientations of fused filament fabrication were tested with a single-batch material manufactured by injection molding serving as a reference. Scans were carried out via micro-computed tomography to assess the void content and distribution with respect to quality. Local material performance was investigated via quasi-static and cyclic tests under tensile loading. The quasi-static tensile tests indicated a significant reduction of Young’s modulus, tensile strength, and strain at fracture for the additively manufactured polymer. The mechanical investigations with cyclic loading intensified this trend of clear reduced mechanical properties due to process-induced defects. The quality assessment revealed void volume contents of the additively manufactured polymer of up to 6.5 % and a void distribution dependent on manufacturing orientation. The results of this study are valuable as design guidelines for highly stressed components and serve as a basis for further characterizations of process-induced defects.

Replica Fabrication of a Greek Paleontological Find Utilising Laser Scanning and Fused Deposition Modeling

2014 ◽  
Vol 657 ◽  
pp. 795-799 ◽  
Author(s):  
Anastasios Chatzikonstantinou ◽  
Dimitrios Tzetzis ◽  
Panagiotis Kyratsis ◽  
Nikolaos Bilalis
Keyword(s):  
Point Cloud ◽  
Laser Scanning ◽  
Fused Deposition Modeling ◽  
Complex Geometry ◽  
Low Cost ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Analytical Methodology ◽  
Fused Deposition ◽  
Deposition Modeling

The current work demonstrates a feasibility study on the generation of a copy, having a highly complex geometry, of a Greek paleontological find utilising reverse engineering and low-cost rapid prototyping techniques. A part of the jaw bone of a cave bear (Ursus spelaeus) that lived during the Pleistocene and became extinct about 10,000 years ago was digitized using a three-dimensional laser scanner. The resulting point-cloud of the scans was treated with a series of advanced software for the creation of surfaces and ultimately for a digital model. The generated model was three-dimensionally built by the aid of a Fused Deposition Modeling (FDM) apparatus. An analytical methodology is presented revealing the step by step approach from the scanning to the prototyping. It is believed that a variety of interested parties could benefit from such an analytical approach, including, production engineers, three-dimensional CAD users and designers, paleontologists and museum curators.

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