Tensile Test Method Research Articles

Modulus of Elasticity and Poisson’s Ratio of Various Metals from the on-off Tensile Testing Method

Modulus of Elasticity and Poisson’s Ratio of Various Metals from the on-off Tensile Testing Method

Measurement of True Stress–True Strain Curve up to Large Strain Extent at Elevated Temperatures in Ti–6Al–4V Alloy with Image Analysis Tensile Test Method

Measurement of True Stress–True Strain Curve up to Large Strain Extent at Elevated Temperatures in Ti–6Al–4V Alloy with Image Analysis Tensile Test Method

Usporedba metoda vlačnog ispitivanja čelika za armiranje

This paper presents a comparison of tensile testing methods of steel for the reinforcement according to HRN EN ISO 15630-1:2010 referring to the norm HRN EN ISO 6892-1:2016. The mechanical properties of the steel are dependent on the test speed. Therefore, according to norm HRN EN ISO 6892-1:2016, the recommended is method A, which uses strain control. The laboratory tensile testing of steel for the reinforcement B500B was tested using the methods A1, A2 and B of norm HRN EN ISO 6892-1:2016.

Mechanical and Electromagnetic Wave Absorption Performance of Carbonyl Iron Powder-Modified Nonwoven Materials

In order to develop carbonyl iron-enhanced electromagnetic wave-absorbing composites, this paper utilizes two different morphologies of carbonyl iron powder (CIP), spherical and flake-like, which are blended with aqueous polyurethane (PU) in three different ratios to prepare impregnating solutions. Polyester (PET) needle-punched nonwoven materials are impregnated with these solutions to produce electromagnetic wave-absorbing composites. First, electromagnetic parameters of the two CIP particle types, spherical carbonyl iron (SCIP) and flake-like carbonyl iron (FCIP), are tested with the coaxial method, followed by calculation of the results of their electromagnetic wave absorption performance. Next, the composites are subjected to microscopic morphology observation, tensile testing, and arched frame method electromagnetic wave absorption performance testing. The results indicate that the microwave absorption performance of FCIP is significantly better than that of SCIP. The minimum reflection loss value for F3, a kind of FCIP-modified nonwoven fabric, at the thickness of 1 mm, at 18 GHz is −17 dB. This value is even better than the calculated RL value of CIP at the thickness of 1 mm. The anisotropic shape of flake-like magnetic materials is further strengthened when adhering to the surface of PET fiber material. Additionally, the modified composites with carbonyl iron exhibit higher tensile strength compared with pure PET. The addition of fibrous skeletal materials is expected to enhance the impedance matching of flake-like magnetic particles, forming a wearable and microwave-absorbing composite.

A Comparative Study on the Mechanical Properties of Open-Hole Carbon Fiber-Reinforced Thermoplastic and Thermosetting Composite Materials.

In this paper, the damage initiation/propagation mechanisms and failure modes of open-hole carbon fiber-reinforced thermoplastic composites and thermosetting composites with tension, compression, and bearing loads are investigated, respectively, by experiments and finite element simulations. The experimental evaluations are performed on the specimens using the Combined Loading Compression (CLC) test method, the tensile test method, and the single-shear test method. The differences in macroscopic damage initiation, evolution mode, and damage characteristics between thermoplastic composite materials and thermosetting composite material open-hole structures are obtained and analyzed under compressive load. Based on scanning electron microscope SEM images, a comparative analysis is conducted on the micro-failure modes of fibers, matrices, and fiber/matrix interfaces in the open-hole structures of thermoplastic and thermosetting composites under compressive load. The differences between thermoplastic and thermosetting composites were analyzed from the micro-failure mechanism. Finally, based on continuum damage mechanics (CDM), a damage model is also developed for predicting the initiation and propagation of damage in thermoplastic composites. The model, which can capture fiber breakage and matrix crack, as well as the nonlinear response, is used to conduct virtual compression tests, tensile test, and single-shear test, respectively. Numerical simulation results are compared with the extracted experimental results. The displacement-load curve and failure modes match the experimental result, which indicates that the finite element model has good reliability.

Effect of Curing Age on Tensile Properties of Fly Ash Based Engineered Geopolymer Composites (FA-EGC) by Uniaxial Tensile Test and Ultrasonic Pulse Velocity Method

Effect of Curing Age on Tensile Properties of Fly Ash Based Engineered Geopolymer Composites (FA-EGC) by Uniaxial Tensile Test and Ultrasonic Pulse Velocity Method

On the development of a high strain-rate tensile testing method for thin low-impedance materials

This work deals with the high strain-rate characterization of paper under uniaxial tension using a Split Hopkinson test bench. An aluminum bar system featuring a highly sensitive hollow transmission bar was used. Paper tests were performed in a strain-rate range between approximately 60 s−1 and 210 s−1. The experimental tests showed that the breaking strength appears to decrease with increasing strain-rate. To verify these results, a digital twin of both the paper specimen and the entire test rig was created in an explicit Finite Element method environment. The numerical model was then used to perform a parameter study with different types of transmission bars. It was shown that the system is quite sensitive to additional masses caused by the specimen fixtures, as well as to drastic reductions in the cross section of the transmission bar. As a result, the transmitted measuring signal can be distorted and may need to be corrected using the digital twin.

Unstable stress-triaxiality development and contrasting weakening in two types of high-strength transformation-induced plasticity(TRIP) steels: Insights from a new compact tensile testing method

The impact of high stress triaxiality on work hardening in transformation-induced plasticity (TRIP) steel has been widely acknowledged, particularly through measurements of the austenite fraction. Understanding this TRIP behavior is crucial for predicting material fracture in press-forming processes. However, the actual flow stresses under high-stress-triaxiality conditions remain largely undetermined. To address this gap, we developed a new tensile testing method using tiny notched round bars to investigate stress-triaxiality-induced work hardening in TRIP steels. The specimens were analyzed using two-dimensional micrometry to allow finite element analyses to identify the flow stress. Additionally, we conducted in situ tensile tests in which their crystal lattice stresses were monitored using synchrotron X-ray diffraction (XRD) to realize mechanism analyses of the unexpected work-hardening behavior identified by the developed tensile testing method. Our combined approach revealed a mutual, unstable increase in the flow stress and stress triaxiality in the TRIP-aided bainitic ferrite steel, which reduced the hardening exponent coefficients and thus induced a higher stress triaxiality. In contrast, the TRIP-aided martensitic steel exhibited a weakening behavior, characterized by a significant decrease in the hardening exponent coefficients in the case of the sharpest notch. XRD analyses showed that microstructural heterogeneity led to an extraordinarily high hydrostatic stress in the austenite phase, accounting for these contrasting behaviors. This finding challenges the established consensus on TRIP steels and suggests the need for a revised framework for their application in press-forming, taking into account stress-triaxiality conditions.

Mechanical Analysis and Constitutive Modeling of Nonlinear Behavior of Silver-based Conductive Ink

Stretchable electronic devices are progressively deployed in many applications of mechanical, electrical, and bio-medical engineering. These circuits are made of stretchable and flexible substrate, as well as conductive ink, and various electronic components. The choice of components and layouts for the substrate and conductive ink can regulate the stretchability of stretchable circuits. On top of that, the substance utilized to create the conductive ink must have high electrical conductivity and strong adherence to the substrate in order to produce a high-quality stretchable printed circuit. Thus, this study focused on the development of stretchable conductive ink using silver powder as a conductive filler and PDMS-OH as a binder. The mechanical properties of the synthesized ink were investigated via simple uniaxial tensile testing method and nanoindentation technique, respectively. Accordingly, the modulus of elasticity, tensile stress and yield stress of the ink were obtained as 5.72 MPa, 1.195 MPa, and 0.86 MPa, congruently at 137% strain before undergoing failure. The experimental stress-strain data was then employed on the elastic-plastic constitutive model to investigate the elastomeric properties of the ink as it is an alternative method of lengthy and expensive procedures of validating different polymers. Moreover, the hardness and reduced modulus of the ink were evaluated by nanoindentation method using 5 mN maximum load with 0.5 mN/s loading/unloading rate and 2 secs holding time. Consequently, the hardness and reduced modulus values were obtained as 1.45 MPa and 34.53 MPa, respectively. These values were further validated by Oliver-Pharr method, and were in a good agreement.

Use of a modified critical fracture strain model for fracture toughness estimation of high strength rail steels

This paper explores the feasibility of estimating fracture toughness (KIC,pred) for nine high-strength rail steels using data from smooth tensile and instrumented ball indentation test methods via a modified critical fracture strain model. The modification focuses on determining the equivalent plastic fracture strain and equivalent plastic strain from tensile and indentation tests, respectively, as well as the characteristic distance needed for estimation of fracture initiation. It shows that stress triaxiality plays a vital role by decreasing the ductility required to initiate fracture, based on the kinetic damage evolution law for a multiaxial stress state. A void growth index model was established from average grain sizes, and then used as the characteristic distance for fracture initiation. At the end, the KIC,pred defined based on equivalent plastic strain from tensile tests showed a strong correlation with KIC determined from ASTM standard method. KIC,pred from indentation also offers the opportunity for ascertaining the possibility of estimating the fracture toughness of high strength rail steels, non-destructively by focusing on the equivalent plastic strain and pressure at the tip of the indenter.

Hybrid Composite Materials Made of Recycled PET and Standard Polymer Blends Used in Civil Engineering.

This paper presents an investigation of the tensile properties of two composites made from recycled polyethylene tetraphthalate, cement-concrete mix and standard polymer-based adhesive mixes, used in the construction industry. To describe tensile behavior, experimental measurements of each component of the resulting composite materials were processed in detail. It presents the possibilities of modifying materials suitable for building structures and at the same time provides an opportunity to get rid of polyethylene tetraphthalate (PET), which has already been recycled several times. Because the resulting composite contains a majority of the composite composition on a fragile basis, its use in practice depends on its simple thrust properties. In this paper, a study of the most important mechanical properties of a previously unused composite is presented. These properties were obtained experimentally using an innovative tensile test method.

Influence of experimental methods on the mechanical properties of silk fibers: A systematic literature review and future road map.

Spider silk fibers are of scientific and industrial interest because of their extraordinary mechanical properties. These properties are normally determined by tensile tests, but the values obtained are dependent on the morphology of the fibers, the test conditions, and the methods by which stress and strain are calculated. Because of this, results from many studies are not directly comparable, which has led to widespread misconceptions in the field. Here, we critically review most of the reports from the past 50 years on spider silk mechanical performance and use artificial spider silk and native silks as models to highlight the effect that different experimental setups have on the fibers' mechanical properties. The results clearly illustrate the importance of carefully evaluating the tensile test methods when comparing the results from different studies. Finally, we suggest a protocol for how to perform tensile tests on silk and biobased fibers.

Mechanical characterization and durability of earth blocks

With the growing awareness of environmental issues, raw earth construction in its various forms is experiencing a renewed interest. In fact, earth is a natural material that limits energy consumption and plays an important role in terms of humidity and temperature regulation. The demand for bio-based building materials and the addition of plant aggregates on earth building bricks is also increasing. This study focuses on the characterization of three unfired commercialized earth adobe bricks with different percentage of plant aggregates. The characterization of the constituents of the different adobe bricks has been first realized by conducting wet sieving tests, sedimentation, Atterberg limit and density tests. The performances of adobe bricks were then investigated and compared in terms of mechanical properties and durability considering freezing-thawing cycles and dry abrasion. The compressive strength is an important property but presents significant variations due to several influencing factors like source, proportion of constituent materials, curing condition, workmanship, in addition to testing procedure. Several specimens have been tested to quantify the compressive strength variability. In addition, as no consensus on the test design and limited data exists on the influence of specimen’s geometry and correlation between testing procedures and mechanical properties, a campaign of unconfined compressive tests has been conducted where several parameters have been varied such as specimen orientation and use of mortar or not. The tensile strength has been also measured with the indirect tensile test method. The effect of freezing thawing cycles was evaluated by subjecting the bricks to unconfined compressive tests after 3, 6, 9 and 12 freezing-thawing cycles. The results show a significant effect of the testing procedure on the compressive strength values. In addition, a decrease in the mechanical properties has been observed for adobe bricks exposed to freezing-thawing cycles.

Study of The Potential of Palm Oil Empty Core Fiber As Composite Materials for Ship Hull

Palm oil is the largest commodity in Indonesia. Pprocessing of oil palm, leaving 20% to 23% empty palm fruit bunches (EFB). Oil palm empty fruit bunches (EFB) is a collection of fiber left behind after separating the fruit from fresh fruit bunches that have been sterilized. Some researchers use natural fibers as an alternative for making composites. This study aims 1. To determine the tensile strength of the alternative material of palm empty fruit bunch fiber. 2. To determine the buckling or bending strength of the alternative fiber material for empty palm oil bunches. The method used is the tensile and bending test method in the process of mixing the fiber material of empty palm oil bunches in the manufacture of composites. The test results obtained were compared with the BKI composite standard. The volume fraction used in this study was 30% polyester resin and 70% EFB fiber, 40% polyester resin and 60% EFB fiber and 50% polyester resin and 50% EFB fiber with NaOH alkaline treatment for 2 hours. The average tensile stress values obtained for each fraction were 27.372 MPa, 24.168 MPa and 25.875 MPa respectively. The values for the bending stress of each fraction are 144.836 Mpa, 149.059 Mpa and 164.682 Mpa respectively.

P35: Characterization and Comparison of Thermoplastic Material Performance Using Pressure-Volume Relationships

Purpose: Characterizing mechanical performance of finished materials can be challenging due to geometric constraints and the effects of downstream processing on raw material behavior. The following describes a more sensitive test method to accurately characterize the performance of a thin polymeric sheet material. Methods: Two different polymers, Thermoplastic Polyurethane, TPU, and Thermoplastic Elastomer, TPE, were selected for characterization. Each was molded and assembled into a manifold. Both polymers were under a constant pressure load over time, as a control and measurement technique. Fluid was injected incrementally into the assembly and the resulting injectate volume was measured by mass difference up to a limit volume to understand material behavior post processing. Results: The plotted pressure-volume relationships were distinct between TPU and TPE at two time intervals, as shown in Figure 1. A reduced pressure response to the same volume at test repetition demonstrated that both materials showed permanent set over time. Volume offset between sample runs illustrated reduced mechanical performance over time due to material creep. Conclusion: The pressure-volume testing method successfully characterized performance of the materials over time to discriminate the material set properties between two thin polymeric sheet material, which could not be detected for a finished component using traditional tensile test methods. This repeated method can be used during material selection in various applications for materials with a manufactured finished component, especially for the medical device industry where polymers are carefully chosen and designed for a specific function.

Study on Temperature-Dependent Uniaxial Tensile Tests and Constitutive Relationship of Modified Polyurethane Concrete.

Modified polyurethane concrete (MPUC) is a new material for steel deck pavements. In service, the pavement is often cracked due to excessive tensile stress caused by temperature changes. In order to study the tensile properties of MPUC in the diurnal temperature range of steel decks, uniaxial tensile tests of MPUC were carried out at five temperatures. Three kinds of specimens and a novel fixture were designed and fabricated to compare the results of four different tensile test methods. The deformation of the specimen was collected synchronously by two methods: pasting strain gauge and digital image correlation (DIC) technique. Based on the experiment, the tensile mechanical properties, failure modes, and constitutive relations of MPUC were studied under the effect of temperature. The research results show that the novel fixture can avoid stress concentration. By observing the fracture surface of the specimens, the bonding performance is great between the binder and the aggregate at different temperatures. The tensile strength and elastic modulus of MPUC decrease with increasing temperatures, while the fracture strain, and fracture energy increase with increasing temperatures. The formulas of temperature-dependent tensile strength, fracture strain, and elastic modulus of MPUC were established, and the constitutive relationship of MPUC is further constructed in the rising stage under uniaxial tension. The calculation results show good agreement with experimental ones.

Analisis Kegagalan Rantai Timing Sepeda Motor Bebek Akibat Beban Tarik dengan Metode Tensile Test

The timing chain is one of the components that play a major role in determining how the engine works by receiving rotation from the crankshaft. This rotation is useful for moving the camshaft which is located in the cylinder head. when the timing chain is loose it often gives an unexpected sound response that can cause the timing chain to quickly stretch. the timing chain will quickly stretch on a motorcycle that rarely gets new and fresh engine oil intake. lack of maintenance on engine oil will have an impact on many things. In addition to the timing chain which is easily loosened due to the lack of a lubricant formula in the engine oil, the research begins with finding and studying various supporting theories related to the strength and elongation of the timing chain. the method used in this research is the tensile test method using the UTM machine. universal testing machine. Material testing machine with a length of 26.5 mm. The research results have 5 specimens for the first specimen on the timing chain having a tensile stress with a value of 2,00 Mpa, a tensile strain with a value of 1,07 and a modulus of elasticity with a value of 1,86 Mpa. the second specimen on the timing chain has a tensile stress with a value of 1.4 Mpa, a tensile strain with a value of 1.07 and a modulus of elasticity with a value of 1.33 Mpa. The third specimen in the timing chain has a tensile stress with a value of 1.79 Mpa, a tensile strain with a value of 1.07 and a modulus of elasticity with a value of 1.67 Mpa. the fourth specimen in the timing chain has a tensile stress with a value of 1.96 Mpa, a tensile strain with a value of 1.15 and a modulus of elasticity with a value of 1.70 Mpa. the fifth specimen in the timing chain has a tensile stress with a value of 5.79 Mpa, a tensile strain with a value of 1. and a modulus of elasticity with a value of 5.79 Mpa.

Crazing Initiation and Growth in Polymethyl Methacrylate under Effects of Alcohol and Stress

Polymer crazing is typically a precursor to damage and considerably reduces the mechanical performance of polymer materials. The concentrated stress caused by machines and the solvent atmosphere created during machining exacerbates the formation of crazing. In this study, the tensile test method was employed to examine the initiation and progression of crazing. The research focused on polymethyl methacrylate (PMMA), both regular and oriented, and the impact of machining and alcohol solvents on the formation of crazing. The results showed that the alcohol solvent influenced PMMA through physical diffusion, whereas machining primarily affected crazing growth via residual stress. Treatment reduced the crazing stress threshold of PMMA from 20% to 35% and produced a threefold increase in its sensitivity to stress. The findings revealed that oriented PMMA exhibited 20 MPa higher resistance to crazing stress compared with regular PMMA. The results also indicated that the extension of the crazing tip and thickening were in conflict, with the crazing tip of regular PMMA severely bending under tensile stress. This study provides valuable insight into the initiation of crazing and the methods of its prevention.

Analysis of Low-Temperature Rheological and Mechanical Properties of Steel Slag Asphalt Mixture Based on Direct Tensile Test

Due to the high resource requirements for specimen preparation and testing equipment, the direct tensile test method is seldom used to study the cracking behavior of asphalt mixture at low temperatures. In this study, three asphalt mixtures were prepared in which all of the basalt or part of the basalt and basalt aggregate was replaced by steel slag. Through the direct tensile creep test and direct tensile relaxation tests including the measurement of creep rate, cumulative strain change rate, and relaxation time, the variation law of rheological properties of low-temperature steel slag asphalt mixture was analyzed and the variation law of viscoelastic properties was explored. Meanwhile, based on the traditional viscoelastic constitutive model, the creep compliance and relaxation modulus were fitted. The mechanical response of the transformation from creep compliance to relaxation modulus of steel slag asphalt mixture was analyzed by a numerical method. The results show that, with the decrease of temperature, the creep rate εs and cumulative strain change rate of the three asphalt mixtures gradually decline, and the relaxation time gradually increases. In particular, when the temperature was reduced from −20°C to −30°C, the cumulative strain change rate of all three asphalt mixtures reached the minimum, which was less than 10%. Moreover, none of them relax to 75% σ0 within 3,600 s at −30°C. The mixture specimens with steel slag replacing all basalt exhibited the best low-temperature deformation adaptation performance under different temperature conditions. Mixture specimens with basalt as aggregate have the worst low-temperature deformation adaptation performance. The relaxation modulus obtained by the measurement of creep compliance is similar to that obtained by testing, and the relaxation modulus calculated through the direct tensile test is more accurate.

Oxidation and Scale Adhesion of a Type 430 Stainless Steel in Ar–CO2 Gas Mixtures at 800 °C

Biogas is an alternative source of fuel potentially used to run solid oxide fuel cells (SOFCs). It mainly consists of CH4 and CO2 which can degrade the SOFC interconnect, which is typically made of stainless steel. To investigate the effect of each gas constituent, we focussed here on the effect of CO2 on high-temperature oxidation behavior of and scale adhesion on the stainless steel interconnect, Type 430 stainless steel. The samples studied were oxidised in CO2 at contents of 5–100% at 800 °C. The oxidation kinetics were found to be parabolic with the rate constant increasing when the CO2 content increased. The scale adhesion was assessed using a tensile-test method. The scale formed in the atmosphere containing higher CO2 content exhibited poorer scale adhesion, as indicated by a lower strain initiating the first spallation and a larger spallation percentage after the first spallation took place. The worsened scale adhesion relates to pores formed at the scale/steel interface. The adhesion energies were further quantified giving the values of about 40–100 J m–2. Oxidation mechanisms were suggested based on the dependence of the parabolic rate constant on the oxygen partial pressure and the inward diffusion of carbon-bearing species.