Nondestructive Evaluation Of Mechanical Properties Research Articles

End-to-end prediction of uniaxial compression profiles of apples during in vitro digestion using time-series micro-computed tomography and deep learning

Machine learning is a promising technique to develop models, which extract relevant information from image data. This study applies convolutional neural networks trained end-to-end to predict the mechanical properties of apples (var. Granny Smith) from micro-CT image data collected during in vitro gastric digestion. Models were trained to directly output compression curves, allowing for representation of complex curve shapes, which changed throughout the digestion process. Models evaluated using 3-fold cross-validation demonstrated high predictive performance, with RMSE of 4.36 N and R2 of 0.939 compared to measured data. This performance was decreased to an RMSE of 14.3 N and R2 of 0.296 when applied to an out-of-distribution dataset. Saliency mapping used to interpret model output demonstrated a mechanistic link between typical biophysical tissue changes and model attention. Overall, the end-to-end deep learning approach represents a promising method for rapid, nondestructive evaluation of mechanical properties during food processing and digestion.

Nondestructive Evaluation of Mechanical Properties of Femur Bone

In a human body, the femur is one of the strongest and longest bones and commonly fractured bone shown in the last decades, especially in elderly humans. Common femur fractures are caused due to violent trauma and severe accidents. The complex structure and response of the bone under dynamic loading conditions will provide extensive information about the mechanical properties of the bone. In this work, we use a non-contact measurement technique using a Position sensing detector (PSD) to measure the natural frequencies and their corresponding mode shapes. The bone sample excited by the impact hammer, and its response is measured using PSD. Sequential measurements are taken on the sample and base; we take the transfer function of the sample with respect to base to measure the natural frequency of bone. Mechanical property such as elastic modulus of the bone is evaluated using measured natural frequencies, and compared with numerical results. The Modulus of elasticity of the bone is found to be 14.8 GPa. Modal analysis was carried to evaluate the natural frequencies and corresponding mode shapes. Numerical results are found to be within 9% of the experimentally measured results. Random vibration analysis was done to emulate the real-time testing for the bone sample. The measured spectrum follows the numerical data. This experimental technique will aid in the nondestructive evaluation of the mechanical properties of the bone sample. Further,this nondestructive technique can be extended for various biological specimens for calculating the mechanical response.

Nondestructive evaluation of mechanical properties of nanostructured Al−Cu alloy at room and elevated temperatures

Abstract The influence of processing variables on the mechanical properties of a nanostructured Al−10wt.%Cu alloy was investigated. Stress−strain microprobe® system (SSM) and its automated ball indentation® (ABI®) test were used for evaluating the mechanical properties of this alloy. The tests were conducted at 21 °C on the bulk samples that were mechanically alloyed for 6 h at two ball-to-powder mass ratios (BPR) of 30:1 and 90:1. Furthermore, the tests were conducted at 200 and 400 °C on the samples that were processed at BPR of 90:1. Increasing BPR resulted in raising the final indentation load from (316±26) to (631±9) N and reducing the final indentation depth from 111 to 103 μm. Regarding the samples that were processed at BPR of 90:1, increasing the test temperature from 21 to 400 °C resulted in decreasing the final load from (631±9) to (125±1) N and increasing the final depth from 103 to (116±1) μm. The sample processed at BPR of 90:1 and tested at 21 °C revealed the highest strength and the least deformability while the sample processed at BPR of 90:1 and tested at 400 °C exhibited the lowest strength and the greatest deformability, as compared to all samples under study.

Exact formula for the horizontal-to-vertical displacement ratio of Rayleigh waves in layered orthotropic half-spaces.

This paper is concerned with the propagation of Rayleigh waves in a compressible orthotropic half-space coated by a compressible orthotropic layer. The main purpose of the paper is to establish an explicit exact formula for the H/V ratio (the horizontal-to-vertical displacement ratio) of the Rayleigh wave. This formula is derived by using the transfer matrix for an orthotropic elastic layer and by the effective boundary condition technique. The formula recovers the H/V formula by Malischewsky and Scherbaum [(2004). Wave Motion 40, 57-67] for the compressible isotropic case and the H/V formula by Love [(1911). Some Problems of Geodynamics (Cambridge University Press, Cambridge)] for the incompressible isotropic case. The effect of anisotropy on the H/V ratio's properties is examined and it is numerically shown that the anisotropy strongly affects the peak and zero frequency of the H/V ratio and its prograde domain as well. As the H/V ratio is a dimensionless quantity and it is easily experimentally measured, the obtained formula will be a useful tool for the nondestructive evaluation of mechanical properties of thin films deposited onto half-spaces. Two numerical examples are performed to show how the obtained formula can be used to extract the material properties of deposited layers from measured values of the H/V ratio.

Magnetic Hysteresis Loop as a Tool for the Evaluation of Microstructure and Mechanical Properties of DP Steels

DP steel of 1.3-mm thickness full hard sheet was heat treated at different temperatures in the range of 700-850 °C with 25 °C step for 15 min soaking followed by water quenching. The variation of the soaking temperatures leads to variation of volume fraction of martensite which was measured by image analysis software in optical microscopy. Mechanical properties of the samples were evaluated using micro Vicker’s hardness test and tensile test machine. Magnetic properties of the samples were measured by MagStar to correlate with the microstructure and mechanical properties of the samples. It was observed that the coercivity of the samples increased linearly with the increase in volume fraction of martensite and mechanical properties. Hence monitoring coercivity would help non-destructive evaluation of mechanical properties of the DP steels. Additionally, it would also helpful for the non-destructive evaluation of variation in heat treatment conditions since coercivity also found to increase linearly with the increase in soaking temperature.

Research on Measurements of Acoustic Characteristics of Nickel-coating Plate and Inversion Method of Elastic Constants

Theoretical model and experimental research is carried out on material elastic constants inversion method of coating plates by acoustic non-destructive test. Taking advantage of the broadband line focus transducer and the precise ultrasonic nondestructive detection system established on our own, obtained the acoustic characterization of thin coating structure. A great amount of data(601 groups) of pulse-echo signals are acquired in an accurate defocusing interval(20 μm). V(f, z) analytical method is applied on the extraction of measured dispersion curves for coating sheets. Associated with the theoretical analysis of wave propagation of coating materials, a computation model of theoretical dispersion curves is established. Comparing the experimental data with the theoretical curves, the acoustic wave velocities are obtained by curve-fitting method, and finally the inversion of elastic constants, e.g. Young's modulus and Poisson's ratio, are achieved. The experimental results agree well with the theoretical ones, while it shows that the inversion method is feasible and reliable. This research laid the foundation of non-destructive evaluation of mechanical properties of coating materials.

Ultrasonic estimate of the modulus of rupture and quantification of the frequency dependent dynamic modulus in Norway Spruce

Ultrasonic measurements allow non-destructive evaluation of mechanical properties of wood. However, it is unclear how these ultrasonically determined properties relate to comparable values obtained by traditional mechanical experiments, e.g., three point bending performed at different probing frequencies. In addition, although a link between the modulus of rupture (MOR) and the modulus of elasticity (MOE) obtained with static methods is established, little research exists on the correlation between the ultrasonically determined dynamic elastic modulus and MOR. Therefore, we set out to link the modulus values obtained by three-point bending to those obtained by ultrasonic measurements at different frequencies. We compared the modalities using a fractional derivative model that theoretically predicts a frequency dependency of the dynamic elastic modulus. We determined MOE and MOR in 102 Norway Spruce samples (340 to 510 kg/m3 density) by three-point bending followed by ultrasonic through-transmission measurements that quantified the dynamic modulus at 500 kHz, 4 MHz, and 8 MHz. This is the first report on such a frequency series for Norway Spruce. Our results provide a conversion factor that permits comparing ultrasonically and statically measured MOE values. Depending on the ultrasonic frequency, correlations ranging from 0.3 to 0.53 between the ultrasonic dynamic modulus and MOR were found.

EFFECTS OF PRESS PRESSURES ON GLUE LINE THICKNESS AND PROPERTIES OF LAMINATED VENEER LUMBER GLUED WITH PHENOL FORMALDEHYDE ADHESIVE

The effects of press pressure on glue line thickness (GLT) and properties of laminated veneer lumbers (LVLs) manufactured from half-round sliced I-214 hybrid poplar clone veneers with phenol formaldehyde adhesives were determined. The results showed that press pressures significantly influenced GLT and properties of LVLs. Results of higher specific gravity, thickness swelling ratio, and mechanical properties, but lower GLT and water absorption ratio were attributed to higher press pressure uses. Optimum properties were obtained by using a press pressure of 10 kg cm-2 in relation to GLT and properties of LVLs. Significant relationships were found between GLT and mechanical properties. GLT may provide reliable information to determine wood bonding quality and may be used for non-destructive evaluation of mechanical properties of wood composites in the future.

Microstructural changes in alloy 625 due to creep and characterization using NDE techniques

Alloy 625 exposed to 60,000 hours of service was re- solution annealed at 1433 K and thermally aged at various temperatures in the range of 923–1123 K to produce different microstructures. The microstructures were characterised using scanning electron microscope. Tensile properties and hardness were determined using nondestructive ball indentation technique. Precise ultrasonic velocity measurements were carried out to evaluate the microstructures. A direct correlation has been observed between ultrasonic velocity and mechanical properties. This study demonstrates the feasibility of applying ultrasonic velocity measurements on-line for nondestructive evaluation of mechanical properties of alloy 625.

Non-destructive evaluation of mechanical properties of poly (vinyl) alcohol-hydroxyapatite nanocomposites

Hydroxyapatite-poly (vinyl) alcohol nanocomposite powder was synthesized using varying poly (vinyl) alcohol concentrations. The dried powder was compacted into micro-porous disks at a load of 4 tons. The disks were sintered at 1200 degrees C to evolve porous nanocomposites. Size and shape of the pores observed in the scanning electron micrographs were quantified by using image processing software. Ultrasound velocity measurements were done to evaluate mechanical properties non-destructively.

A magnetic yoke probe for in situ magnetic measurements

AbstractA probe with a magnetic yoke for nondestructive evaluation of mechanical properties was developed. This probe can evaluate the magnetic properties of ferromagnetic materials without machining them to a ring core or frame core shape, that is, it can perform in situ measurements. In this paper, the magnetic properties measured by the magnetic yoke probe are compared with the mechanical properties and a good correlation is found, suggesting a potential use of the probe for nondestructive evaluation of mechanical properties in ferromagnetic materials. The effect of an air gap between the probe and the specimen was also investigated in order to address possible contact problems in industrial applications. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 165(3): 1– 7, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20588

A New Method for Nondestructive Evaluation of Mechanical Properties Using Instrumented Indentation Technique

The development of the instrumented indentation test (IIT), which gives accurate measurements of the continuous variation in indentation load as a function of depth, has paved the way to assessing tensile properties and residual stress in addition to hardness by analyzing the indentation load-depth curve. In this study, analytic models and procedures are presented for evaluating tensile flow properties and residual stress states using IIT. Tensile properties were obtained by defining representative stress and strain beneath the spherical indenter. The evaluation of residual stress is based on the concepts that the deviatoric stress part of the residual stress affects the indentation load-depth curve, and that analyzing the difference between the residual stressinduced indentation curve and the residual stress-free curve permits evaluation of the quantitative residual stress in a target region.

Magnetic Yoke Probe for In-situ Magnetic Measurements

A probe with a magnetic yoke for nondestructive evaluation of mechanical properties was developed. This probe can evaluate magnetic properties of ferromagnetic materials without machining them to a shape of ring core or frame core, that is, in-situ measurements. In this paper, magnetic properties measured by the magnetic yoke probe were compared with mechanical property. The magnetic properties measured by the probe have a good correlation with those mechanical properties. This shows a potential to apply the probe to NDE of mechanical properties in ferromagnetic materials. The effect of air gap between the probe and the specimen was also investigated, to consider the problem of contact in practical use.

MODAL ANALYSIS OF LIVING SPRUCE USING A COMBINED PRONY AND DFT MULTICHANNEL METHOD FOR DETECTION OF INTERNAL DECAY

Modal analysis is a widely accepted tool for non-destructive evaluation of mechanical properties of materials and structures. In this paper, a partial modal analysis is used to examine whether internal decay in living trees can be detected by studying the resonance frequencies of the trees. We examine the resonance frequencies of living spruce of species Picea abies (Norway spruce) by means of the pulse response due to the impact of a hammer onto the surface of the trunk. The response is measured by 12 accelerometers positioned around a cross-section of the tree, and modelled by sums of damped sinusoids. The temporal parameters are determined using Prony's method, and the spatial parameters associated to the circumferential mode shapes are determined using the discrete Fourier transform on the set of weights yielded by Prony's method. A total of 94 living trees have been examined. It is found that the mode shapes are almost clean sinusoids, and that reproducible results are obtained although the impact excitations are applied by hand force. The results show that a certain mode shape is found in recordings from all trees but one, and that it possesses the lowest temporal frequency in each tree. Furthermore, it is found that the temporal frequency of this mode shape often is lower for decayed trees than for sound trees, and that the difference in frequency seems to be related to the extent of decay. There is, however, a large scatter of the sound trees, which leads to a partial overlap of the two groups of sound and decayed trees. It is concluded that more parameters are required to further separate the groups from each other.

Non-Destructive Evaluation of Mechanical Properties of Magnetic Materials

ABSTRACTA magnetic-based non-destructive evaluation (NDE) method, which employs Barkhausen effect and measurement of the hysteresis loops, is used to correlate the magnetic and mechanical properties of ultra low carbon (ULC) steel. In particular, the NDE method was used to detect small deviations from linearity that occur in the stress-strain curve well below the 0.2% offset strain, and which generally defines the yield point in materials. Results show that three parameters: jumpsum and jumpsum rate (derived from the Barkhausen spectrum), and the relative permeability (derived from the B-H loops) varies sensitively with small permanent strains, and can be related to the plastic deformation in ULC steels. Investigation of micromagnetic structure revealed that plastic deformation leaves a residual stress state in the samples; the associated magneto-elastic energy makes the favorable easy axis of magnetization in a given grain to be the one that lies closest to the tensile axis. The consequence of this realignment of domains is that wall motion becomes intergranular in nature (as opposed to intragranular in unstrained samples). As a result, the more complex grain boundaries instead of dislocations, become the dominant pinning sites for domain walls. These observations provide a microscopic interpretation of the observed changes in the measured magnetic properties.

CORRELATION BETWEEN MECHANICAL PROPERTIES AND ACOUSTICAL ANISOTROPY IN PRESTRAINED PLATE

Abstract Nondestructive evaluation of mechanical properties in plastically deformed states using ultrasonic shear waves is discussed. Round bar tension tests, Charpy V impact tests and ultrasonic wave velocity measurements are reported on mild steel plate (SS41), high strength steel plate (HT80) and aluminum alloy plate (A5083), prestrained in tension under various conditions. Correlations between the results of the material tests and acoustical anisotropy are examined. The material dependence of the relation between material property and ultrasonic measurements is also investigated.In the plate prestrained up to the plastic region. strength increases and ductility decreases withincreasing prestrain. Though the acoustical anisotropy increases with increasing prestrain in 5541 and HT80, the opposite result is obtained in A5083. Relationships between mechanical properties and the acoustical anisotropy, in all the plates prestrained up to the plastic region, are represented approxirnately by straight lines o...

Nondestructive Evaluation of Mechanical Properties in Prestrained Steel by Ultrasonic Techniques

Nondestructive Evaluation of Mechanical Properties in Prestrained Steel by Ultrasonic Techniques