Resistance Curves Research Articles

Experimental study on mass transfer behavior and mechanism in nuclide-containing sandy soil under temperature gradient

The level of nuclear waste emergency disposal is an important factor restricting the rapid development of the nuclear energy industry under the trend of global energy revolution. To promote the effective application of artificial ground freezing (AGF) for the treatment of nuclear wastewater leakage, the mass transfer and migration mechanism of key nuclides (137Cs, 90Sr, and 129I) during unidirectional freezing of saturated silty sand were elucidated in this study. Temperature sensors and a nuclear magnetic resonance (NMR) were used to explore the internal temperature and moisture variation characteristics of nuclide-containing sandy soil during the freezing. Furthermore, using the designed device, a unidirectional freezing of different nuclide-containing sandy soils was performed to establish a relationship between the development characteristics of the freezing front and the mass transfer of nuclide. The results show that the T2 spectrum of nuclide-containing sandy soils has the most significant change from 0 °C to -1 °C, and the bound water content of I-containing sandy soil remains evident change when the temperature decreases below -1 °C. During unidirectional freezing, owing to the influence of the freezing front on nuclide migration, the resistivity curve exhibits a V-shaped jump, and the concentration peaks appear in turn along the freezing direction and show a stepwise increase. Nuclide mobility is closely related to the freezing rate of the corresponding location. With an increase in freezing thickness, the freezing rate decreases and the nuclide mobility increases. Owing to the combined influence of water-ice phase transition, concentration gradient and matrix suction in sandy soil, the concentration only increases within a small area at the face of the freezing front. The differences in migration behavior of nuclides in sandy soil driven by temperature gradient is mainly due to the different degrees of compression of nuclide ion on the diffusion double electric layer of soil particles, which results in different forms of unfrozen water within the sandy soils. The overall mobility of the three nuclides shows the following sequence: Cs>I>Sr. In the practical application of AGF, attention should be paid to the effects caused by the rapid migration of low-valence cationic nuclides and the retention of high valence cationic nuclides in the frozen wall.

Analysis of electrical resistance measurements as a potential determination method for coating thickness on powders

The electrical resistance of conductive and non-conductive coatings on non-conductive and conductive powders, respectively, is investigated under increasing external load. A specially designed equipment was used to deposit coatings on small and light as well as heavy powdery substances by DC magnetron sputtering. Several reference methods to predict or measure the absolute film thickness on powders are discussed.When measuring the electrical resistance of insulating powders coated with a metal, in this case hollow glass microspheres (HGMs) coated with copper, under increasing load, a typical resistance curve is found. This resistance curve is discussed in terms of percolation theory and the Heckel equation for powder compaction. The influence of coating thickness of the conductive coating is then evaluated and other factors like inhomogeneity of the coating are discussed. To reduce the influence of measurement parameters, selected experiments are interpreted under the concept of a force per grain, which is introduced and explained.To further substantiate the typical electrical resistance curve, stabilized and non-stabilized NMC811 powder is coated with aluminium and zirconium oxides of different thicknesses, corresponding to a conductive powder with an insulating coating. When comparing measurements for stabilized and non-stabilized powder, the perspective for electrical resistance measurements under increasing load becomes apparent, as it is possible to even detect surface modifications which are not known a priori.

Experimental and CFD Resistance Validation of Naval Combatant DTMB 5415-51 Model

The hull model of the surface combatant DTMB 5415 has been selected as a recommended benchmark naval ship for computational fluid dynamics (CFD) validation for resistance analysis. CFD is used to present a method for predicting surface combatant ship resistance. The resistance calculations of a 3 m DTMB 5415 hull model was compared using experimental and CFD techniques. The bare hull shape experiments were set up and carried out at the towing tank facilities at the Military Technical College's Hydrodynamic Laboratory in Egypt. A benchmark test will ensure that the equipment, procedures, and estimates of uncertainty are adequate. For the purpose of model validation, CFD calculations for a DTMB 5415-51 model are performed using three different mesh sizes for Froude numbers ranging from 0.10 to 0.40. For the same Froude numbers and free model conditions, results from towing tank experiments on the model's resistance, sinkage, and trim are presented. The numerical simulations are quantitatively consistent. The numerical results are compared in terms of wave field and resistance coefficients to determine the accuracy of the solution parameters. As evidenced by the resistance curves, the experimental investigation appears to provide very good agreement, indicating that the CFD model is capable of simulating the steady flow around a ship hull with acceptable accuracy and can thus be used as a supplement to laboratory model tests for ship design and ship hydrodynamic research.

Computer vision techniques applied to automatic detection of sinusoids in borehole resistivity imaging – A comparison with the MSD method

In this research computer vision techniques are applied to borehole resistivity imaging in order to establish an alternative procedure to the mean square dip (MSD) processing. The MSD is regularly applied to detect sinusoids and dips automatically in borehole imaging and dipmeter logs. The present proposal is based on Gabor’s filters, morphological transformations, Hough’s transform, and clustering techniques. The MSD method and the computer vision proposal were tested in 1012 m of images, showing 7.986% of false positives for the MSD processing and 0.879% for the computer vision approach. This methodology tries to emulate the geologists behavior when they make image interpretation; instead of making correlations between resistivity curves like the MSD does. There are no special computer requirements, and it can be applied directly in the field for quick well-site dip results. This procedure can be easily integrated into log units and most commercial borehole-imaging processing software. The processing workflow was developed in python using standard libraries.

Analysis of the influence characteristics and correction effect of the mine direct current method in advance detection of roadway cavities

To ensure safety during coal mining, the DC electric method is frequently used for the advanced detection of concealed water-rich abnormal geological bodies located ahead of a drivage roadway. However, to some extent, the accuracy of the detection is influenced by the roadway cavity, resulting in a deviation from the actual location of the anomaly. To investigate this phenomenon, the principle of advanced detection based on a spheroidal physical model was analyzed via “comparative analyses” and “simulated” methods using COSMOL Multiphysics software. Following the principle of numerical simulations, the influence of the roadway cavity on the accuracy of the advanced DC detection method was introduced, and the ratio of apparent resistivity calculated from actual data to that calculated only with the roadway cavity was carried out to obtain the roadway correction coefficient. This coefficient was employed to correct the apparent resistivity data for advanced 3-D detection. Additionally, the response characteristics of the anomalies at different electrode layout locations in the roadway were discussed. The results show that the ratio method effectively corrects the influence of the roadway during advance detection using the DC electric method and simultaneously improves the resolution of geological anomalies and the accuracy of positioning. Additionally, the influence of the roadway was related to the relative positions of the electrodes along the roadway. When the electrodes are set at the junction of the floor and the sidewall, the obtained resistivity curve is less affected. Therefore, the resolutions of the anomalies are higher, and their positioning is more accurate. Furthermore, a practical application of the ratio method indicated that the corrected curves reflected the geological anomalies better.

Mechanical-electrical coupling behaviors of 3-D carbon fiber angle-interlock woven composites under quasi-static and cyclic tension

Mechanical-electrical coupling behaviors of carbon fiber composites is important to structure health monitoring (SHM). Here, we investigated the mechanical–electrical coupling behaviors of 3D carbon fiber angle-interlock woven composites (3DAWC) under tensile loading. Different loading modes including monotonic, cyclic, and fatigue tests were adopted to find the relationship between electrical resistance and tension damages. We also developed a mechanical–electrical constitutive model to reveal the relationship between internal damage modes and the electrical resistance. The tensile deformation and damage of the 3DAWC lead to the increase of the electrical resistance. The increased range is related to the degree of the deformation, damage, and damage accumulation. The transition point of the electrical resistance change represents the initial point of warp yarn longitudinal damages. The irreversible deformation of warp yarns leads to an increase in resistance after unloading. The stress–strain curve and the resistance vs. strain curve can be obtained simultaneously to reveal the internal structural deformation and inner damage mechanisms.

Characteristics of Chaotic Weak Reflection in Carbonate Fracture-Cavity Reservoirs: A Case Study of Ordovician Reservoirs in Block 10 of the Tahe Oilfield, Tarim Basin, China.

The identification of carbonate reservoirs is a critical task in oil and gas exploration. Chaotic weak reflection is an important type of reflection characteristic in carbonate reservoirs. Widespread distribution of chaotic weak reflection has been observed in the Ordovician Yijianfang Formation in the Tahe area. However, there is still a lack of systematic research on the distribution, characteristics, reservoir space, and reservoir types of chaotic weak reflection in the Tahe area. To address this issue, this study conducted a comprehensive analysis of multiscale data and found that chaotic weak reflections are distributed within 100 ms below the top interface of the Middle Ordovician. Seismic profiles exhibit a "string of pearls" with a "tail" or "pearl-like" widening feature. On well logs, all three porosity curves exhibit localized peaks, with increases in acoustic (AC) and compensated neutron (CNL) and decreases in density (DEN), while the deep and shallow lateral resistivity (RD, RS) curves show positive amplitude differences. In the FMI, they are represented by dark sinusoidal curves and dark small patches. Based on these response characteristics, two types of reservoir spaces are identified for chaotic weak reflections: high-angle vertical fractures and caves with heights less than 7 m, which can form independent reservoirs or fracture-cavity complexes. Three types of reservoirs are distinguished: fracture, cavity, and cavity-fracture types.

Developing a Single-Specimen Technique for Low-Temperature R-Curve Determination of Asphalt Concrete Using a Modified Unloading Compliance Method

Fracture resistance curves (R-curves) have served as a robust tool in characterizing the entire fracture process of engineering materials. However, obtaining such curves for asphalt concrete (AC) mixtures is cumbersome due to the non-linear inelastic behavior of the mixtures. In this research, a single-specimen technique is developed based on the unloading compliance method which is used for metals. AC mixtures with limestone aggregate and PG58-22 binder were prepared. Beam specimens were fabricated and single-edge notched beam (SE(B)) fracture testing was conducted at low temperatures. A loading-partial unloading regime was used in the experiments and crack growth increments were captured by digital images throughout the tests. Using a multi-variable regression analysis, modified compliance equations were obtained for AC and R-curves of the mixtures could be constructed. It was revealed that the R-curve developed by ASTM E1820 compliance method could potentially overestimate the resistance of the mixtures against low-temperature fracture. The constructed R-curve exhibits a lower semi-vertical region addressing lower resistance of the mixture in the crack blunting phase. Also, the post-peak phase of the fracture shows a significantly lower slope in the constructed R-curve which denotes lower resistance of the mixture against unstable crack propagation.

IDENTIFICATION OF SEPARATION CURVES OF STRONGLY CONTRASTING ENVIRONMENTS USING COMPLEX ANALYSIS METHODS

When modeling mass transfer processes (for example, filtration) in porous media, there may be cases of the existence of highly permeable layers, which are separated from the corresponding studied parts by some curves that must be found (identified) in the process of solving the problem. When constructing a mathematical model of the corresponding physical process, we will consider a highly permeable medium as "ideally (theoretically infinitely) permeable." In this case, the desired curve can be considered an equipotential line. This work considers the stationary process of fluid movement in a homogeneous horizontal layer of infinitely large dimensions - a soil massif, which is limited by infinite sections of curves, in particular by the desired curve of theoretical water resistance and the horizontal axis, on which the local speed of movement is known. On the basis of the methods of conformal reflections and total images, an approach to the identification of the curve of the separation of media is proposed. The constructed algorithm is modified for solving nonlinear inverse boundary value problems on quasi-conformal mappings of curvilinear polygonal regions bounded by uncertain streamlines and equipotential lines. The feature of the method proposed is that the summary representation formulae allow to explicitly write the solution to the localized linear (main) part of the obtained system of equations. The unknown coefficients are determined here by solving a non-linear system generated solely by the boundary conditions and numerical analogues of the Cauchy–Riemann equations.

Investigation on crack extension resistance curve of aligned steel fiber‐reinforced cement‐based composites

AbstractIn this study, an analytical method was proposed to predict the crack extension resistance curve (KR curve) of aligned steel fiber‐reinforced cement‐based composites (ASFRC). The three‐point bending tests were carried out on notched ASFRC specimens. Based on the predicted results, the influence of size effect and fiber dosage on KR curves of ASFRC specimens was discussed. Finally, the relationship between KR curves of ASFRC and steel fiber‐reinforced cement‐based composite (SFRC) specimens was investigated. The results show that the analytical results agree well with the experimental ones. The KR curve of ASFRC specimen has size effect and increases with fiber dosage. The ASFRC specimen shows a 30% improvement in the crack extension resistance at peak load over the SFRC specimen when the fiber volume dosage is 0.8%, and the improvement becomes more pronounced with increasing fiber dosage. When the KR curves of ASFRC and SFRC specimens are the same, the fiber consumption can be reduced by at least 40%.

Experimental study of the fracture of CT specimens printed in PLA as a function of the raster width

The FDM (Fused Deposition Modelling) additive manufacturing process is characterised by a large number of process variables that determine the mechanical properties and quality of the manufactured parts. When printing layer by layer, the filaments constituting the layer are welded on the one hand between them in the same layer and on the other hand between the superimposed layers, this welding develops on the contact surfaces (raster width) along the deposited filaments. The quality of this welding determines the resistance to crack propagation between filaments and between layers. This article aims to study the effect of the width of the raster on the resistance to crack propagation in a structure obtained by FDM.We have developed an experimental approach from CT specimens to determine the tensile strength of polylactic acid (PLA) polymers, considering the J-Integral method. And given the complexity of the problem, three cases of raster width (l=0.42 mm, l=0.56 mm and l=0.68 mm) have been treated.According to the results obtained (J, ∆a), the resistance to crack propagation in the parts printed by FDM seems to be better when the width of the filament is small. Indeed, the energy necessary to break the specimen is relatively greater than in the case of a larger width. This finding was confirmed by comparing the values of J for a given advancement of the crack for the three cases studied.In order to present an exhaustive study, we focused on the effect of raster widths (including 0.42 mm, 0.56 mm to 0.68 mm) on the crack propagation of printed PLA. This study is in progress for other printing parameters. To highlight the cracking mechanisms, microscopic observations will be developed in greater depth at the SEM.Our analysis can be used as decision support in the design of FDM parts. In effect, we can choose the raster width that would provide the resistance to crack propagation desired for a functional part.In this article, we analysed the damage mechanism of CT specimens printed by FDM. This subject represents a new direction for many lines of research. For our study, we used the J-Integral theoretical approach to study the fracture behaviour of these parts by determining the resistance curves (J-∆a).

Study on Migration Monitoring Technology of Chromium-Contaminated Site Based on Dual-Frequency Induced Polarization Method

In order to reveal the migration process of chromium-contaminated sites, COMSOL5.6 software was used to build the initial model of the chromium pollution source and analyze the migration change characteristics over time based on the rule of groundwater movement and Convection–Dispersion equation. COMSOL provides fully coupled multiphysics modeling for most engineering fields. The results show that: the permeable layer with a high permeability coefficient during the migration of chromium pollutants has a strong adsorption effect on the heavily polluted part, and it will enhance the lateral diffusion of the polluted area within a short period. Based on the migration model, the intermediate gradient and the symmetrical quadrupole sounding model are built. The variation law of apparent amplitude frequency and apparent resistivity under flat and undulating terrain is analyzed based on the dual frequency IP (Induced Polarization) method. The results show that: The intermediate gradient detection is better than the symmetrical quadrupole sounding in the correspondence between the peak value of apparent amplitude frequency and the valley value of apparent resistivity. The arrangement of the bathymetric measurement point in the center of the projected edge of the pollution field can be a better way to monitor the pollution. Monitoring with the intermediate gradient detection device and the symmetrical quadrupole sounding device creates “multiple peaks” in the curve as it passes through the valley. Arranging the power supply electrodes on the mountain frontiers on both sides of the raised peaks and synthesizes the apparent amplitude frequency and apparent resistivity curves of the pollution field, which can effectively determine the specific orientation of the heavily polluted area of the pollution field. This research makes theoretical additions to the migration characteristics of the Cr pollution field. It provides technical guidance for the real-time monitoring of the pollution field, which is of positive significance for promoting ecological and environmental protection.

Electron Beam‐Irradiated Au/h‐BN/Au Cross‐Point Memristors

Applying 2D materials to build memristors is a promising strategy that has attracted great interest in the semiconductor field in recent years. Although the study of memristors based on chemical vapor deposition (CVD) with lattice defects has been well established, the applications and detailed knowledge of the ones using mechanical exfoliation with good lattice structures are still scarce. Herein, the resistive switching behavior of an array of 3 μm × 3 μm cross‐point Au/25.7 nm mechanically exfoliated h‐BN/Au memristors is investigated after a controllable electron beam doping process. An electron beam irradiation strategy is first proposed to treat h‐BN memristors with intact lattice structure. Devices with moderate electron beam irradiation, which is about 1500 or 2000 mC cm−2, show good resistive switching curves. The memristor device has a repeatable resistive switching behavior, an on/off ratio of 108, a set voltage as low as 5 V, and a retention higher than 1000 s. This strategy provides an alternative method to improve the performance of memristor. Mechanical exfoliated h‐BN preserves the lattice structure, which is an immediate advantage to fabricate memristor using it compared to that fabricated by CVD.

Growth and characterization of the sputtered type-II topological semimetal PdTe2 thin films and PdTe2/Co60Fe20B20 heterostructures

The topological phases such as Dirac/Weyl semimetals are recently observed in Layered transition metal dichalcogenides (TMDs). The family of materials XTe2 (with X = Pd, Pt and Ni) possesses a type-II topological semimetal (TSM) phase. Here, we report the synthesis of the layered XTe2 thin films using the industry-friendly sputtering technique. The structural and morphological qualities of the sputtered-grown XTe2 thin films are analysed using X-ray diffraction and Raman measurements. The crystallites are highly oriented along the c-axis of the sapphire substrate, which suggests that growth is driven by van der Waals epitaxy. The magneto-transport measurements namely temperature-dependent resistivity and magnetoresistance measurement in out-of-plane field configuration are performed on PdTe2 thin films. The semi-metallic trend and superconducting transition are observed in the temperature-dependent resistivity curve. The weak antilocalization behavior observed in the magnetoconductance curves at a low magnetic field signifies the possibility of a non-zero Berry phase, possibly arising from the Dirac fermionic nature of electronic states. The spin dynamics measurements are performed on the PdTe2/Co60Fe20B20 bilayers. The effective spin mixing conductance and spin current density are found to be ∼2×1020m-2and 2.5MAm-2, respectively in PdTe2/Co60Fe20B20 bilayer which are quite larger than those observed in heavy metal-ferromagnets bilayers, and comparable to MBE-grown topological insulator-ferromagnets heterostructures. This work paves the way to synthesize Te-based layered TMDs using the industrially viable sputtering technique, and demonstrates the prospects for exploring the topological superconductive phase in PdTe2 films and large spin-charge conversion efficiency in PdTe2/Co60Fe20B20 heterostructures.

Design of a real-time monitoring system and frequency agility electric field device to prevent CaCO3 scaling on heat exchange surfaces

In this paper, experiments are used to investigate the CaCO3 scale inhibition performance on the heat transfer surface in various frequency ranges of the frequency agility electric field device. The device can produce a high-speed, erratic variant of the type frequency agility pulse signal in the range of 0–400 kHz, and obtain a peak voltage that is adjustable by a power amplifier circuit between 10 and 150 V per peak. Scale formation on the heat transfer surface is slowed down or avoided as a result of the collision of Ca2+ and CO32− in water caused by the electric field. The scale inhibition experiment monitoring and regulation system is designed to monitor and adjust temperature and flow parameters in real time, observe fouling resistance curve, and store all data instantly. According to the experimental findings, various frequency ranges of electric field treatment reduce scale's fouling resistance, with 79 % serving as the highest scale inhibition rate. The device has well scale inhibition performance, as evidenced by the findings of the comparison of surface scale and scanning electron microscopy.

Determination of the fracture toughness of a 9Cr ODS steel fuel cladding using the pin loading Tension test

A Pin Loading Tension (PLT) test was developed to evaluate the fracture behavior of thin-walled tubes. The fracture resistance curve (J-R curve) was determined from the load-CMOD curve using the single specimen technique based on the elastic unloading method following the procedure described in the ASTM E1820-22e1 standard [1]. However, the standard does not provide the necessary functions, geometric function f(a/W) and plastic factor ηpl, to apply the methodology to the PLT test. In this work, the geometric functions needed to evaluate the crack length from the unloading compliance, which allows to highlight effects not seen in the past and the elastic and plastic parts of the J-integral were determined using finite element analysis. Special care was taken to consider the effects of contact and friction between the test specimen and the loading device. The methodology was then applied to experimentally study the crack growth resistance of a 9Cr ODS (Oxide Dispersion Strengthened) steel tube, which is a candidate material for fuel claddings of future fast-neutron reactors.

Crack extension resistance for a general three-point bending concrete beam

Expressions of the crack extension resistance for a general three-point bending (TPB) concrete specimen were developed. Based on the proposed general expressions, the effects of span/height ratios on the fracture processes of TPB concrete beams were studied using two types of specimens, i.e. the beams with the same section but different spans and the beams with the same span but various heights. Results indicate that (1) the crack extension resistance curves (KR-curves) increased with the crack propagation. (2) The KR-curves and fracture process zone curves were not affected by the span/height ratios, i.e. the KR-curve can be considered as a criterion to describe the crack propagation in a structure. (3) The calculated crack tip opening displacement was not affected by the specimen span but increased with increasing the specimen height. (4) The stability analysis of crack propagation was also described based on the KR-curve.

Response of the Verwey transition in magnetite to controlled point-like disorder induced by 2.5 MeV electron irradiation

Controlled point-like disorder induced by low temperature 2.5 MeV electron irradiation was used to probe the nature of the Verwey transition in magnetite, Fe3O4. Two large single crystals, one with optimal transition temperature, TV≈121 K, and another with TV≈109 K, as well as magnetite magnetosome nanocrystals harvested from the lysed cells of the marine magnetotactic vibrio Magnetovibrio blakemorei strain MV-1, TV≈110 K, were examined. Temperature-dependent resistivity is consistent with the semiconductor-to-semiconductor (insulator) sharp, step-like Verwey transition from a state with a small bandgap of around 60 meV to a state with a large bandgap of about 300 meV. The irradiation causes an up-shift of the resistivity curves above the transition without transition smearing or broadening. It also causes an apparent down-shift of the resistivity maximum at high temperatures. In the lower TV crystal, the electron irradiation drives the transition temperature into a “forbidden” interval of TV , believed to separate the first order from the second order phase transition. Contrary to this belief, the transition itself remains sharp and hysteretic without a significant change in the hysteresis width indicating the strong 1st order character of the Verwey transition for all TV values. The separate 2nd order - looking transition is likely due to sample inhomogeneities. We conclude that the sudden change of the bandgap accompanied (or driven) by the monoclinic distortion and the change of magnetic anisotropy is the reason for the Verwey transition in magnetite and the effect of additional disorder is mostly in the smearing of the sharp gap edges near the Fermi level.

Fatigue Threshold R-Curves for Dental Lithium Disilicate Glass–Ceramics

Chemical and mechanical fatigue degradation in ceramic materials is generally inconspicuous yet ubiquitous, to the effect that clinical fractures still consist of the main cause of failure in all-ceramic restorations. Implications of this span wide, from a reduced survival prognosis for the affected teeth, including more frequent and increasingly invasive procedural interventions, to the financial burden borne by individuals and health care systems. To suffice as an effective corrective, restoration lifetimes need only to be extended so to outlive the patient. That opens a box of problems from a materials science standpoint, entailing inherent deficiencies of brittle materials to resist mechanical and environmental challenges. Efforts in developing more damage-tolerant and fatigue-resistant restoratives go thus hand in hand with understanding intrinsic mechanisms of crack growth behavior under conditions that simulate the oral environment. Here we developed experiments using size-relevant sharp precracked specimens with controlled size and geometry (truncated semielliptical crack in the surface-crack-in-biaxial-flexure method) to establish a relationship between crack size and strength. The tangent method was used to construct envelopes for the quasi-static resistance curves (R-curves), which served as template for deriving residual cyclic R-curve analogs. By means of experimentally obtained stress–cycle curves, lifetime and fatigue parameters were employed within a mechanistic framework to reveal constitutive toughening mechanisms during subcritical growth under cyclic loading in a wet environment. Using 3 modern dental lithium disilicate glass–ceramics, we demonstrate the extent of R-curve degradation up to a threshold of 10 million cycles (~30 y in service) and draw parallels between the scope of fatigue degradation and the size of the microstructural units responsible for toughening mechanisms in glass–ceramic materials. Our results indicate that larger microstructural elements endow glass–ceramics with a higher reaching quasi-static R-curve at the onset but degrading more rapidly to comparable levels of lithium disilicates having submicrometric and nanometric crystal phases.

Seismic site response analysis of liquefiable soil deposits focusing on the ground surface response spectrum

A numerical algorithm is developed for conducting one-dimensional non-linear ground response analysis of layered sites, capable of reproducing liquefaction phenomena and accounting for the simultaneous dissipation of excess pore water pressure through soil grains. Τhe shear wave propagation algorithm is based on the plasticity constitutive model for sand Ta-Ger, expressed in a one dimensional p-q space form. This model demonstrates remarkable versatility in representing complex patterns of the cyclic behavior of sand, such as stiffness decay and strength reduction due to pore-water pressure buildup. The calibration of the model is based on shear modulus reduction and damping curves for drained loading conditions, as well as liquefaction resistance curves for undrained conditions. A detailed presentation of the numerical model formulation is provided, outlining the numerical approach for solving the wave propagation and consolidation differential equations. To validate model predictions, the recorded seismic ground response of the Port Island array during the 1995 Kobe earthquake is utilized. Furthermore, the model is applied to estimate the elastic response spectra at the surface of soil profiles with liquefiable layers (ground type S2) as per EC8:2004. The investigation involves the ground response analysis of various soil p3rofiles, all including a liquefiable zone, excited by a suite of earthquake motions at their base. The acceleration time histories are extracted from the PEER Ground Motion Database, having characteristics compatible with the NGA-estimated response spectrum at the bedrock as well as key seismological parameters such as the earthquake magnitude Mw and the horizontal distance from the fault RJB. Two different methods are employed for selecting the base excitations: amplitude-scaled records to match a target response spectrum and spectral-matched records. From the results, an idealized response spectrum is derived in terms of the design spectrum parameters S, η, ΤΒ and TC. The findings demonstrate that the idealized ground surface response spectrum is minimally sensitive to the method used for base excitation selection.