scholarly journals Comparative behavior of local hyperelastic lowgrade rubbers for low-cost base isolation

2019 ◽  
Vol 276 ◽  
pp. 01001
Author(s):  
Tavio ◽  
Usman Wijaya
Keyword(s):  
Base Isolation ◽  
Low Cost ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Low Grade ◽  
Test Results ◽  
Laboratory Test Results ◽  
Planar Shear ◽  
Yeoh Model ◽  
Hyperelastic Model

As the second largest rubber producer in the world, Indonesia has a very potential opportunity to support the development of rubber base isolation. Various grades of rubber are produced by the local rubber manufacturers starting from the low to high grade rubbers. In the study, the local rubbers were also compared to the rubbers from another developing country, e.g. India. The laboratory test results used to develop the suitable constitutive model for hyperelastic material and then compared to the hyperelastic model of Shahzad et al. Several tests on the local low-grade rubbers have been conducted, namely the uniaxial tensile, planar shear, and equibiaxial tensile tests. From the tests, it can be concluded the behavior of the local low-grade rubber can be fitted with the Ogden model different from the characteristic of rubber tested by Shahzad et al. which was fitted with the Yeoh model.

Vaccine Passport - A blockchain based architecture for secure, tamper-resistant, privacy-enhanced credentialing mechanism of vaccination and verification of test results (Preprint)

2021 ◽  
Author(s):  
Hsiu An Lee ◽  
Hsin-Hua Kung ◽  
Wei-Chen Wu ◽  
Jai Ganesh Udayasankaran ◽  
Yu-Chih Wei ◽  
...  
Keyword(s):  
Data Protection ◽  
Low Cost ◽  
Vaccination Rate ◽  
Data Accuracy ◽  
Test Results ◽  
Public And Private ◽  
Global Pandemic ◽  
Laboratory Test Results ◽  
Encryption And Decryption ◽  
International Data

BACKGROUND The coronavirus disease 2019 (COVID-19) is an ongoing global pandemic caused by severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2). The prevention and treatment methods for COVID-19 are not yet clear. At present, there are at least 287 preventive vaccines against COVID-19 in the world, of which 5 vaccines are available for emergency use as of June 2021, but none has completed clinical trial. Nevertheless, with the development of vaccines, disease conditions in various countries are gradually controlled. OBJECTIVE The vaccination rate has increased in time, and activities in various countries have gradually recovered. Therefore, the focus of the next stage is confirming and proving that everyone is vaccinated to ensure that those without vaccines will not become a breach in the next wave of diseases. The vaccination or RT-PCR test results are all certified and verified by paper documents issued by hospitals or testing institutions. Meanwhile, falsified documents are a major risk factor in confirming the vaccination status and laboratory test results. Although the Vaccine Passport (VP) may become an important key to future global activities based on the current strategy, the problems of document verification and data use among countries have not yet been resolved. METHODS The blockchain architecture proposed in this research can be applied together by public and private entities and be rapidly expanded. Furthermore, the open ledger of blockchain achieves transparency and data accuracy. On the other hand, smart contracts (SCs) achieve authorization and authentication, while the encryption and decryption mechanisms achieve data protection. In order to make it globally available, the international data standard “Fast Healthcare Interoperability Resource (FHIR)” is adopted into this research. In general, this blockchain architecture can achieve global vaccine passport verification accurately and at a low cost. RESULTS The open nature of the blockchain contributes to establishing transparency and data accuracy. Total three entities are included in this blockchain architecture. All of the authorization are public in the open ledger. The smart certificate enables authorization and authentication, while the encryption and decryption mechanism ensure data protection. This proof of concept demonstrates the design of blockchain architecture which, when adopted, can achieve global vaccine passport verification accurately and at a cost country can afford. An actual vaccine passport case was established and demonstrated in this study. Open blockchain, individually authorized authentication mechanisms, and international standard vaccine passports were adopted. CONCLUSIONS Blockchain architecture is used to build the authentication process of an executable international vaccine passport, with advantages of low cost, high interoperability, effectiveness, security and verifiability.

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.

Tensile properties of the FFF-processed thermoplastic polyurethane (TPU) elastomer

2021 ◽  
Author(s):  
Budi Arifvianto ◽  
Teguh Nur Iman ◽  
Benidiktus Tulung Prayoga ◽  
Rini Dharmastiti ◽  
Urip Agus Salim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Low Cost ◽  
Thermoplastic Polyurethane ◽  
High Strength ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Fused Filament Fabrication ◽  
Raster Angle ◽  
Manufacturing Techniques

Abstract Fused filament fabrication (FFF) has become one of the most popular, practical, and low-cost additive manufacturing techniques for fabricating geometrically-complex thermoplastic polyurethane (TPU) elastomer. However, there are still some uncertainties concerning the relationship between several operating parameters applied in this technique and the mechanical properties of the processed material. In this research, the influences of extruder temperature and raster orientation on the mechanical properties of the FFF-processed TPU elastomer were studied. A series of uniaxial tensile tests was carried out to determine tensile strength, strain, and elastic modulus of TPU elastomer that had been printed with various extruder temperatures, i.e., 190–230 °C, and raster angles, i.e., 0–90°. Thermal and chemical characterizations were also conducted to support the analysis in this research. The results obviously showed the ductile and elastic characteristics of the FFF-processed TPU, with specific tensile strength and strain that could reach up to 39 MPa and 600%, respectively. The failure mechanisms operating on the FFF-processed TPU and the result of stress analysis by using the developed Mohr’s circle are also discussed in this paper. In conclusion, the extrusion temperature of 200 °C and raster angle of 0° could be preferred to be applied in the FFF process to achieve high strength and ductile TPU elastomer.

Development and application of hyperelastic model for diaphragm considering the influence of temperature

2019 ◽  
Vol 08 (03) ◽  
pp. 1950010
Author(s):  
Lidong Wang ◽  
Xiongqi Peng ◽  
Mingrui Liu
Keyword(s):  
Constitutive Model ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Model Parameters ◽  
Influence Of Temperature ◽  
Nonlinear Fitting ◽  
Element Simulation ◽  
Hyperelastic Model ◽  
User Material Subroutine ◽  
Solid Foundation

The basic mechanical properties of a diaphragm under various temperatures in hot diaphragm preforming of composites are obtained by uniaxial tensile tests. A constitutive model considering the influence of temperature is accordingly developed to characterize its large deformation behavior. Model parameters are obtained by nonlinear fitting experiment data. The constitutive model is implemented in ABAQUS through the user material subroutine UHYPER. The developed constitutive model is verified by simulating the covering deformation of the diaphragm over a C-type mold. Finally, as an application of the developed hyperelastic model, an optimal design of a support bar in the hot diaphragm preforming process is implemented. The constitutive model lays a solid foundation for the finite element simulation and process optimization of the hot diaphragm forming (HDF) of carbon composites.

scholarly journals The influence of sample geometry and size on porcine aortic material properties from uniaxial tensile tests using custom-designed tissue cutters, clamps and molds

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0244390
Author(s):  
Ming Pei ◽  
Donghua Zou ◽  
Yong Gao ◽  
Jianhua Zhang ◽  
Ping Huang ◽  
...  
Keyword(s):  
Material Properties ◽  
Tensile Testing ◽  
Tensile Tests ◽  
Optimal Choice ◽  
The Other ◽  
Uniaxial Tensile ◽  
Test Results ◽  
Uniaxial Tensile Testing ◽  
Dog Bone ◽  
Weibull Theory

The aim of this study was to identify the influence of specimen geometry and size on the results of aortic uniaxial tensile tests using custom-designed tissue cutters, clamps and molds. Six descending thoracic aortas from pigs were used for rectangular sample tests, in which the circumferential and axial specimens had widths of 6 mm, 8 mm and 10 mm. The other six aortas were used for the dog-bone-shaped sample tests and were punched into circumferential, axial and oblique specimens with widths of 2 mm, 4 mm and 6 mm. We performed uniaxial tensile tests on the specimens and compared the test results. The results showed that mid-sample failure occurred in 85.2% of the dog-bone-shaped specimens and in 11.1% of the rectangular samples, which could be caused by Saint-Venant’s principle. Therefore, rectangular specimens were not suitable for aortic uniaxial tensile testing performed until rupture. The results also showed that the size effect of the aorta conformed to Weibull theory, and dog-bone-shaped specimens with a width of 4 mm were the optimal choice for aortic uniaxial tensile testing performed until rupture.

Hyperelastic characterization of synthetic mesh for abdominal wall hernia repair

MRS Advances ◽  
2019 ◽  
Vol 4 (57-58) ◽  
pp. 3181-3185
Author(s):  
Javier Ortiz Ortiz ◽  
Georgina Carbajal de la Torre ◽  
Miguel Villagómez Galindo ◽  
Marco Antonio Espinosa Medina ◽  
Hilda Aguilar Rodriguez
Keyword(s):  
Hernia Repair ◽  
Abdominal Wall ◽  
Abdominal Wall Hernia ◽  
Tensile Tests ◽  
Synthetic Mesh ◽  
Uniaxial Tensile ◽  
Marquardt Algorithm ◽  
Hyperelastic Model ◽  
Abdominal Wall Hernia Repair

ABSTRACTHernia is defined as the protrusion of one or several internal organs through an opening in the cavity that contains them due to a tissue defect, abdominal wall surgery by means of synthetic meshes is the most common method used for hernia repair, however, postsurgical effects can range from some discomfort, to chronic pain and even the reappearance of the hernia due to a poor mechanical adaptability between the synthetic tissue and the host tissue. The knowledge of the mechanical properties of the materials involved in hernia repair is fundamental in the understanding and subsequent solution of this type of problems. In this work, experimental data were obtained by means of uniaxial tensile tests in two perpendicular directions of commercial meshes used in hernia repair. The tests were carried out on the UniVert® machine of the CellScale® brand. Anisotropic mechanical behavior is observed due to the structure of the mesh and the interaction between each of the yarns that make it up. The data found vary with respect to the direction of traction and also has non-linear hyperelastic behavior, so the adjustment of curves was made through a hyperelastic model in the COMSOL Multiphysics® software through the Levenberg-Marquardt Algorithm for the characterization of these materials.

Analysis of temperature and strain rate dependencies of softening regime for tempered martensitic steel

2017 ◽  
Vol 52 (4) ◽  
pp. 226-238 ◽  
Author(s):  
Johanna Eisenträger ◽  
Konstantin Naumenko ◽  
Holm Altenbach ◽  
Elisabetta Gariboldi
Keyword(s):  
Strain Rate ◽  
Mechanical Behaviour ◽  
Elevated Temperatures ◽  
Martensitic Steel ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Test Results ◽  
Strain Localisation ◽  
Surface Measurements ◽  
Softening Stage

This article aims to analyse the influence of temperature and strain rate on the mechanical behaviour of the high-chromium martensitic steel X20CrMoV12-1. The analysis is based on two series of high-temperature uniaxial tensile tests. In a first series, the tensile tests are conducted until rupture, and temperature as well as strain rate are varied systematically. The corresponding stress–strain curves show an extended softening stage. In order to examine softening, it is crucial to distinguish between microstructural changes and strain localisation due to necking. For this reason, a tensile test at low strain rate is performed several times, while the test is terminated at different strain levels in order to examine the onset of necking. Based on the test results and surface measurements of the deformed specimens, the strain level at which necking starts is determined, and possible interactions between softening and necking are discussed. The tensile tests have been conducted in order to calibrate a mechanical model which supplies reliable predictions on the material behaviour under different loading scenarios at elevated temperatures. For this reason, a framework based on microstructural processes is presented in the second part of the article. The model applies a binary mixture approach in conjunction with an iso-strain concept. Furthermore, backstress and softening variables are introduced to consider hardening and softening effects. This procedure results in a system of three differential equations describing the mechanical behaviour.

Characterization of Doped SAC Solder Materials and Determination of Anand Parameters

2015 ◽  
Author(s):  
Sudan Ahmed ◽  
Munshi Basit ◽  
Jeffrey C. Suhling ◽  
Pradeep Lall
Keyword(s):  
High Reliability ◽  
Low Cost ◽  
Tensile Tests ◽  
Material Behavior ◽  
Lead Free ◽  
Uniaxial Tensile ◽  
Strain Rates ◽  
Stress Strain ◽  
Free Solder ◽  
Viscoelastic Constitutive Model

In the electronic packaging industry, it is important to be able to make accurate predictions of board level solder joint reliability during thermal cycling exposures. The Anand viscoelastic constitutive model is often used to represent the material behavior of the solder in finite element simulations. This model is defined using nine material parameters, and the reliability prediction results are often highly sensitive to the Anand parameters. In present work, three new doped lead free solder materials recommended for high reliability applications have been chemically analyzed and then mechanically tested in order to determine the nine Anand parameters. The alloys are referred to as Ecolloy (SAC_R), CYCLOMAX (SAC_Q), and Innolot by their vendors. The first two doped alloys (SAC_R and SAC_Q) were found to be composed of Sn, Ag, Cu, and a single X-element dopant. Such solders are commonly referred to as SAC-X in the literature. For the third material (Innolot), three different dopants are present along with Sn, Ag and Cu. The EDX method was used to determine the approximate chemical composition of the materials, and Bismuth (Bi) was found to be the X-additive for both SAC_R and SAC_Q. In addition, the SAC_R material was found to have no silver (Ag), which is the reason it is marketed as a low cost (economy) material. The nine Anand parameters were determined for each unique solder alloy from a set of uniaxial tensile tests performed at several strain rates and temperatures. Testing conditions included strain rates of 0.001, 0.0001, and 0.00001 (sec−1), and temperatures of 25, 50, 75, 100, and 125 C. The Anand parameters were calculated from each set of stress-strain data using an established procedure that is described in detail in the paper. The mechanical properties and the values of Anand parameters for these new doped alloys were compared with those for standard SAC105 and SAC405 lead free alloys. Although the SAC_R material does not have any silver, it was shown to have better mechanical behavior than SAC105 due to the presence of Bismuth (Bi) along with a little higher percentage of Copper (Cu). The SAC_Q and Innolot materials were shown to have significantly higher strength than SAC405. After deriving the Anand parameters for each alloy, the stress-strain curves have been calculated for various conditions, and excellent agreement was found between the predicted results and experimental stress-strain curves.

scholarly journals Investigation on Granular Medium Forming Formability of TA1 Titanium Alloy Cylinder-Shaped Parts

2021 ◽  
Author(s):  
Biao Hu ◽  
Gaoshen Cai ◽  
Jubo Fu ◽  
Yanxi Xin ◽  
Kangning Liu ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Deep Drawing ◽  
Granular Medium ◽  
Simulation Analysis ◽  
Tensile Tests ◽  
Alloy Sheet ◽  
True Stress ◽  
Uniaxial Tensile ◽  
Test Results ◽  
Forming Quality

Abstract In order to investigate the formability of the granular medium forming (GMF), based on the Mohr-Coulomb constitutive model with the tri-axial compression test of granular medium and the true stress-strain curves of TA1 titanium alloy from uniaxial tensile tests, the numerical simulation of TA1 titanium alloy sheet deep drawing with finite element method was performed, and the deep drawing tests were also carried out. Simulation analysis and test results show that the GMF process is suitable for titanium alloy sheets, and can effectively improve the uniformity of the wall thickness of the formed parts, reduce the tendency of wrinkles and improve the forming quality.

Small Punch Testing of Sanicro 25 Steel and its Correlation with Uniaxial Tests

2017 ◽  
Vol 734 ◽  
pp. 70-76 ◽  
Author(s):  
Petr Dymáček ◽  
Ferdinand Dobeš ◽  
Luboš Kloc
Keyword(s):  
Uniaxial Stress ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Test Results ◽  
Small Punch ◽  
Punch Test ◽  
Uniaxial Creep ◽  
Force Relaxation ◽  
Deflection Rate ◽  
Good Agreement

Small punch testing under constant deflection rate, constant force and constant deflection (i.e. force relaxation) were performed on the new austenitic steel Sanicro 25. Constant deflection rate experiments were correlated to uniaxial tensile tests at room temperature and 700°C with the help of several empirical relationships. Small punch creep testing was performed in as received state. Correlation of the small punch results with uniaxial creep test results was done and the force/stress ratio Ψ and kSP parameter were determined. The constant deflection small punch test was correlated with the uniaxial stress relaxation test and good agreement was reached.

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