Nondestructive Evaluation of Materials Tensile Strength via Nonlinear Acoustics Data

2021 ◽  
Author(s):  
Julian Ehrler ◽  
Alexander Solodov ◽  
Yannick Bernhardt ◽  
Marc Kreutzbruck
Keyword(s):  
Tensile Strength ◽  
Mechanical Response ◽  
Tensile Tests ◽  
Iteration Scheme ◽  
Third Order ◽  
Stress Strain ◽  
The Third ◽  
Static Tensile ◽  
Nonlinear Acoustic ◽  
Quadratic And Cubic Nonlinearities

Abstract The nonlinear acoustic approach is assessed for applications as a nondestructive tool for reconstructing stress-strain curves and quantifying the ultimate tensile strength for variety of materials. The direct algorithm uses the polynomial stress-strain expansion up to the third power of strain and the literature data on the second-order nonlinearity parameters to calculate relevant segments of the stress-strain curves. Since the third-order nonlinearity parameters are unknown for majority of materials the calculations used an iteration scheme to obtain closer approximations to the experimental data available from static tensile tests. The solution to the inverse problem identifies the range of the nonlinearity parameters for a given tensile strength and enables to categorize the contribution of the quadratic and cubic nonlinearities in mechanical response for different materials.

High Strain Rate Tensile Behavior of Carbon Fiber Reinforced Aluminum Laminates

2005 ◽  
Author(s):  
Yuanxin Zhou ◽  
Pingwen Mao ◽  
Mohammad F. Uddin ◽  
Shaikh Jeelani
Keyword(s):  
Carbon Fiber ◽  
Strain Rate ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Strain Rate Range ◽  
Fiber Reinforced ◽  
Stress Strain ◽  
Static Tensile ◽  
Carbon Fiber Reinforced ◽  
Good Agreement

In this paper, loading and loading-unloading tests of carbon fiber reinforced aluminum laminates (CRALL) have been carried out in a tensile impact apparatus, and quasi-static tensile tests have been performed on a MTS-810 machine. Complete stress-strain curves of composite in the strain rate range from 0.001–1200 1/s have been obtained. Experimental results show that CRALL composite is a strain rate sensitivity material, the tensile strength and failure strain both increased with increasing strain rate. A linear strain hardening model has been combined with Weibull distribution function to establish a constitutive equation for CRALL. The simulated stress-strain curves from model are in good agreement with the test data. The analysis of the model shows that the Weibull scale parameter, σ0, increased with increasing strain rate, but Weibull shape parameter, β, can be regarded as a constant.

Effect of crystalline structure on the mechanical response of polypropylene under cyclic deformation

2013 ◽  
Vol 33 (2) ◽  
pp. 181-190
Author(s):  
Aleksey D. Drozdov ◽  
Rasmus Klitkou ◽  
Jesper de C.Christiansen
Keyword(s):  
Numerical Simulation ◽  
Crystalline Structure ◽  
Residual Strain ◽  
Mechanical Response ◽  
Tensile Tests ◽  
Semicrystalline Polymers ◽  
Uniaxial Tensile ◽  
Cyclic Tests ◽  
Stress Strain ◽  
Minimum Stress

Abstract To evaluate the influence of crystalline structure on the mechanical behavior of polypropylene (PP), uniaxial tensile cyclic tests with a mixed program (oscillations between fixed maximum strains and the zero minimum stress) were performed on isotactic PP (iPP) manufactured by the Ziegler-Natta catalysis method, metallocene catalyzed PP (mPP), and annealed mPP. Although the stress-strain diagrams of iPP and mPP under tension are quite similar, their responses under unloading differ markedly. The residual strain (measured as the strain under retraction down to the zero stress) of iPP strongly exceeds that of non-annealed mPP, and annealing of mPP increases this difference. To rationalize these findings, constitutive equations are developed in cyclic viscoelasticity and viscoplasticity of semicrystalline polymers, and adjustable parameters in the stress-strain relations are found by fitting the observations. The ability of the model to describe the observed phenomenon and to predict the mechanical response in multi-cycle tensile tests, with various deformation programs, is demonstrated by numerical simulation.

Mechanical Response of T300/BMP350 Composites under Tensile Loading at Room and Elevated Temperatures

2014 ◽  
Vol 1035 ◽  
pp. 138-143
Author(s):  
Ping Zhou ◽  
Pu Rong Jia ◽  
Wen Ge Pan
Keyword(s):  
High Temperature ◽  
Failure Modes ◽  
Elevated Temperatures ◽  
Mechanical Response ◽  
Effect Of Temperature ◽  
Matrix Composites ◽  
Stress Strain ◽  
Damage And Failure ◽  
Different Temperatures ◽  
Static Tensile

In this paper, the effect of elevated temperature on the behavior of carbon fiber-reinforced T300/BMP350 unidirectional laminates was studied by loading static tensile on 0°, 90°and ±45° lay-up. The stress-strain relationships of the laminates under different temperatures were obtained. The effect of temperature on the mechanical properties of materials was systematically studied. The damage and failure mechanisms of the material were studied by analyzing the material stress-strain curves and the failure modes. Results show that the T300/BMP350 polyimide matrix composites have a strong resistance to high temperature. For 0° and 90° lay-up, the retentions of tensile strength and modulus are more than 80% and 50%, respectively. High temperature has little effect on the material failure modes. Finally, based on the test results, an empirical formula which relates strength and temperature of the material was fitted.

Stress and strain measurements in static tensile tests

2012 ◽  
Vol 19 (3) ◽  
pp. 531-540 ◽  
Author(s):  
Stanisław Adamczak ◽  
Jerzy Bochnia ◽  
Czesław Kundera
Keyword(s):  
Tensile Strength ◽  
Measurement Errors ◽  
Room Temperature ◽  
Tensile Tests ◽  
Stress And Strain ◽  
Accuracy Of Measurements ◽  
Strength Tests ◽  
Static Tensile ◽  
Limiting Errors

Abstract The paper deals with the accuracy of measurements of strains (elongation and necking) and stresses (tensile strength) in static room-temperature tensile strength tests. We present methods for calculating measurement errors and uncertainties, and discuss the determination of the limiting errors of the quantities measured for circular and rectangular specimens, which is illustrated with examples.

scholarly journals The effect of edge interlaminar stresses on the strength of carbon/epoxy laminates of different stacking geometry

2006 ◽  
Vol 71 (4) ◽  
pp. 421-431 ◽  
Author(s):  
Momcilo Stevanovic ◽  
Milan Gordic ◽  
Daniela Sekulic ◽  
Isidor Djordjevic
Keyword(s):  
Tensile Strength ◽  
Normal Stress ◽  
Edge Effect ◽  
Edge Effects ◽  
Free Edge ◽  
Tensile Tests ◽  
Boundary Region ◽  
Stacking Sequence ◽  
Interlaminar Stresses ◽  
Static Tensile

The effect of edge interlaminar stresses on strength of carbon/epoxy laminates of different stacking geometry: cross-ply, quasi-isotropic and angle-ply laminates with additional 0? and 90? ply was studied. Coupons with two widths of laminates with an inverse stacking sequence were tested in static tensile tests. The effect of edge interlaminar stresses on strength was studied, by comparing the values of the tensile strength of laminate coupons of the same width with an inverse stacking sequence, as well as, by comparing the values of the tensile strength of the same lay-up laminate coupons but of different widths. The edge effects were analyzed by observing failure, identifying the interlayer where axial cracks at the free edge were initiated or inhibited and by computing interlaminar stresses and strains in the interlayer near the free edge of the coupon. The established edge effect was first correlated to the sign of the normal edge interlaminar stress. The extent of the edge effect was then successfully correlated to the edge interlaminar normal stress normalized to the size of the edge boundary region in which the stress appeared.

scholarly journals Stiffness and Strength Anisotropy in the Tensile Response of Weft Knitted Fabric-Reinforced Peek- and Pet-Composites

1996 ◽  
Vol 5 (3) ◽  
pp. 096369359600500 ◽  
Author(s):  
J. Karger-Kocsis ◽  
T. Czigány ◽  
J. Gaál ◽  
M. Ostgathe
Keyword(s):  
Mechanical Response ◽  
Tensile Tests ◽  
Thermoplastic Composites ◽  
Knitted Fabric ◽  
Strength Anisotropy ◽  
Strong Anisotropy ◽  
Tensile Response ◽  
Weft Knitted Fabric ◽  
Static Tensile ◽  
Good Agreement

The mechanical response of weft knitted carbon (CF) and glass fibre (GF) fabric-reinforced thermoplastic composites with polyetheretherketone (PEEK) and polyethyleneterephthalate (PET) was studied by dynamic-mechanical thermal analysis (DMTA) and static tensile tests. A strong anisotropy was observed in both stiffness and strength when the specimens were loaded in wale (stronger) and course direction (weaker) of the knit, respectively. The anisotropy factor was estimated by considering the relation of the loop numbers in course and wale direction, that resulted in good agreement with the experimental data.

scholarly journals Modified Osgood Equation for Acacia Mangium

2019 ◽  
pp. 33-35
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Acacia Mangium ◽  
Tensile Tests ◽  
Test Results ◽  
Direction Parallel ◽  
Static Testing ◽  
Significant Difference ◽  
Static Tensile ◽  
Wood Grain

The purpose of this study is to identify the Osgood’s coefficient of species and the Modified Osgood Equation for Acacia mangium. Acacia mangium trees were cut to produce oven-dried Small Clear Specimens that were then tested until fracture. Results were gathered from static tensile tests in the direction parallel (0° angle), perpendicular (90° angle) and at 30° angle to the wood grain. All test results confirmed that the Acacia mangium wood is brittle as there was no obvious necking observed on the test specimens. From the static testing, the Osgood’s coefficient of species for Acacia mangium, (a), is identified algebraically to be 0.49. Acacia mangium, by nature, has a significant difference in the strengths parallel and perpendicular to the grain line. The finalized results of the Ultimate Tensile Strength for 15-year old Acacia mangium demonstrated that the Ultimate Tensile Strength in parallel and perpendicular to the grain directions are 143.87 MPa and 6.32 MPa respectively, while the Ultimate Tensile Strength at 30° grain angle is 32.985 MPa. An extreme reduction of 95.6% of the Ultimate Tensile Strength was identified between 0° and 90° grain angles with a decreased value from 143.87 MPa to 6.32 MPa.

scholarly journals Tensile strength of a vegetated and partially saturated soil

2020 ◽  
Vol 195 ◽  
pp. 03001
Author(s):  
Alessandro Fraccica ◽  
Enrique Romero ◽  
Thierry Fourcaud ◽  
Mercedes Sondon ◽  
Luis Gandarillas
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Mechanical Response ◽  
Triaxial Compression ◽  
Strength Criterion ◽  
Tensile Tests ◽  
Bare Soil ◽  
New Device ◽  
Direct Shear Tests ◽  
Partially Saturated

Vegetated soil’s shear strength has been usually assessed through direct shear tests and under triaxial compression stress paths while less is known about its behaviour under tensile stress. Tensile strength and shrinkage-induced cracking play a crucial role in the hydro-mechanical response of earth structures exposed to drying/wetting cycles. For this purpose, a new device for direct tensile tests has been designed and used to let plants grow in compacted soil samples. The equipment consists of two cylindrical moulds connected to each other by a soil bridge in which failure upon pulling is induced due to geometrical constraints. Different soil’s mechanical responses were observed depending on whether suction was low or high. Indeed, it was detected an increase of soil tensile strength and a more brittle behaviour as suction was increasing. However, at the same suction, vegetated soil’s response was more ductile than that of the corresponding bare soil. Results were analysed within a shear strength criterion for partially saturated soils. The analysis evidenced an increase in shear strength in the vegetated soil. A correlation was found between this increase and the roots’ mechanical and morphological features.

Effect of Preheating and Post-Curing Time on the Mechanical Properties of Epoxy Resin

2013 ◽  
Vol 22 (5) ◽  
pp. 096369351302200
Author(s):  
Mostefa Bourchak ◽  
Adnan Khan ◽  
Khalid A. Juhany
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Epoxy Resin ◽  
Tensile Strain ◽  
Tensile Tests ◽  
Test Machine ◽  
Curing Time ◽  
Cure Cycle ◽  
Static Tensile

The purpose of this study is to compare the mechanical properties in the form of ultimate tensile strength, ultimate tensile strain and Young's modulus of an epoxy resin at different curing cycles. The work carried out consisted of investigating the effect of preheating time and then the effect of post-curing time at the same temperature. Five repeats of static tensile tests were then carried out using universal test machine. Results indicated that compared to a shorter epoxy resin preheat duration of 15 min at 80°C, a longer duration of 30 min at 80°C of preheating degrades the material ultimate tensile strength and ultimate tensile strain leading to a suffer material. However, compared to no further post-curing of the epoxy resin, a two-hour post-cure duration at 80°C slightly increased the ultimate tensile strength and significantly decreased the ultimate tensile strain making the material even suffer than in the case of preheating. The implication is that in-house cure cycle tests should be carried out to characterize the resin instead of exclusively relying on resin manufacturer proposed cure cycles.

scholarly journals Low- and High-Cycle Fatigue Behavior of FRCM Composites

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5412
Author(s):  
Angelo Savio Calabrese ◽  
Tommaso D’Antino ◽  
Pierluigi Colombi ◽  
Carlo Poggi
Keyword(s):  
Cyclic Loading ◽  
High Cycle Fatigue ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Strain Curve ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Stress Strain ◽  
Static Tensile

This paper describes methods, procedures, and results of cyclic loading tensile tests of a PBO FRCM composite. The main objective of the research is the evaluation of the effect of low- and high-cycle fatigue on the composite tensile properties, namely the tensile strength, ultimate tensile strain, and slope of the stress–strain curve. To this end, low- and high-cycle fatigue tests and post-fatigue tests were performed to study the composite behavior when subjected to cyclic loading and after being subjected to a different number of cycles. The results showed that the mean stress and amplitude of fatigue cycles affect the specimen behavior and mode of failure. In high-cycle fatigue tests, failure occurred due to progressive fiber filaments rupture. In low-cycle fatigue, the stress–strain response and failure mode were similar to those observed in quasi-static tensile tests. The results obtained provide important information on the fatigue behavior of PBO FRCM coupons, showing the need for further studies to better understand the behavior of existing concrete and masonry members strengthened with FRCM composites and subjected to cyclic loading.

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