Static Curves Research Articles

Using the nonlinearity of a PEM water electrolyzer cell for its dynamic model characterization

The voltage response of a water electrolyzer at low frequencies is characterized by a combination of a static polarization curve and dynamic, capacitive effects. In this paper, a model combining these two phenomena is created, which incorporates the Butler–Volmer equation in parallel with a capacitance in order to produce differential equations for the activation overpotentials separately on both electrodes. A parameter fitting methodology is then developed for obtaining the seven model parameters from a set of low-frequency, high-amplitude dynamic waveform measurements. The method is further implemented in an electrolyzer modeling toolbox for MATLAB. The model built in this study is proven to predict well both static and dynamic voltage responses down to the 1Hz frequency. At higher frequencies and at small amplitudes the model reduces to the Randles equivalent circuit, and in a static case to the polarization curve of the cell. The proposed methodology can be used for probing individual electrode properties with full-cell measurements and providing a reliable tool for simulating water electrolyzer voltage responses with arbitrary waveforms and amplitudes.

Mechanical and thermal properties of glass fiber reinforced polymer-clay nanocomposites

Abstract The effect of Montmorillonite (MMT) nanoclay on static mechanical and thermal characteristcs of glass fiber-reinforced polymer (GFRP) composites is studied. The static tensile properties of epoxy/MMT nanoclay, which are important properties of GFRP composites, are investigated. The predicted stress-strain curves of epoxy with 0 and 1 wt.% of nanoclay follow experiments. The predicted elastic modulus and tensile strength of epoxy with 3 wt.% of nanoclay are 74 and 230% higher than neat epoxy. For GFRP composites with 0, 1, 3, and 5 wt.% of MMT nanoclays, the measured tensile strengths are 587, 600, 628, and 724 MPa, and flexural strengths are 626, 726, 906, and 542 MPa. For composites with former nanoclays, interlaminar shear strengths are 23, 25, 31, and 28 MPa, and Izod impact strengths are 83, 94, 207, and 145 kJ/m2. Thus, mechanical strengths of composites with 0–5 wt.% of nanoclays improve considerably than pristine sample. The predicted static tensile stress-strain curves of GFRP composites with above nanoclays follow experimental behavior. For GFRP composites with 0 and 1 wt.% of MMT nanoclays, glass transition temperatures are 91 and 101°C, and storage moduli at ambient temperature are 35 and 41 GPa. The thermal conductivities of GFRP composites with 0, 1, and 3 wt.% of MMT nanoclays at ambient temperature are 0.32, 0.36, and 0.42 W/(m·K). Thus, thermal properties of composites are affected significantly on addition of nanoclays.

Applicability of linear models in modeling dynamic behavior of alkaline water electrolyzer stack

Linear equivalent circuit models are commonly used to estimate the effect of current ripple on the performance of water electrolyzers, thus it is important that the validity of this approach is examined. The effect of the amplitude and frequency of the sinusoidal current ripple on the performance of the alkaline water electrolyzer stack is studied experimentally. The increased current ripple amplitude produces additional losses in the electrolyzer stack, while the effect of ripple frequency appears to be insignificant. Linear models based on an equivalent circuit and polarization curve tangent are compared with waveform measurements with differing ripple amplitudes and frequencies to study their dynamic modeling capabilities. Under dynamic operation the experimental results show that operating voltage differs considerably from the static polarization curve, especially at low operating currents, due to nonlinear behavior. It is also shown that the dynamic equivalent circuit model using only linear components is not enough to accurately model electrolyzer behavior under dynamic operation.

Characterization of compressive fatigue behavior and acoustic emission analysis of Ti6Al4V cellular lattice materials fabricated by laser powder bed fusion

AbstractThis study investigates the mechanical properties and fatigue performance of Ti6Al4V cellular lattice materials (CLMs) featuring five distinct unit cell types (BCC‐Z, BCC, Octet, Truncated cuboctahedron [TCO], and Trabecular) at a relative density of 25%. Compression tests were conducted to assess static properties, including Young's modulus and yield strength. Subsequently, compression–compression fatigue tests (R = 0.1) were performed to evaluate fatigue behavior. Acoustic emission analysis was employed during static and fatigue tests to explore the potential for failure prediction. Results reveal that BCC‐Z and TCO exhibit slightly higher Young's moduli, surpassing 20 GPa, while BCC, Octet, and Trabecular display moduli ranging from 6 to 12 GPa. Regarding normalized fatigue behavior, BCC‐Z demonstrates superior fatigue resistance, followed by TCO. Notably, the acoustic emission parameters significantly correlate with the unit cell type. Lastly, a strong relationship between the initiation of failure and changes in acoustic emission parameters is observed, establishing a meaningful link between the static and fatigue curves and acoustic emission results.

A novel approach for quantifying dynamic impacts on steel frames induced by instantaneous interior column loss

This research presents an innovative approach to accurately quantify dynamic impacts on the steel frame structure resulting from the instantaneous loss of an interior column. This methodology effectively calculates the dynamic amplification factor (DAF) when the steel frame reaches its collapse limit state and predicts the structure's deformation under such a scenario. Central to this approach is the conversion of the static load-deformation curve, pertinent to a scenario of interior column loss, into a dynamic force load-deformation curve using the concept of energy balance. A comprehensive parametric analysis was conducted to study how different structural parameters, such as beam depth, span, slab thickness, rebar diameter, and slab aspect ratio, affect the enhancement factor (i.e., the ratio of collapse resistance to yield resistance). A pragmatic formula for determining enhancement factor was subsequently suggested. Moreover, this study delved into how these structural parameters influence the dynamic amplification factor at the collapse state, revealing a notable dependency of dynamic amplification factor on the slab aspect ratio that an increasing aspect ratio correlates with a rising dynamic amplification factor trend. The manuscript also presented a detailed methodology for computing the dynamic deformation of frame structures in the event of an instantaneous interior column loss. The results of the case study show that the proposed method closely matches the accuracy of numerical analyses, with differences falling within a 15% range.

Characteristics and analysis of static strain response on typical asphalt pavement using fiber Bragg grating sensing technology

To study the real internal strain response of asphalt pavement and provide crucial data for optimizing pavement design. By burying the fiber grating sensors on site, the strain tests of four asphalt pavement structures under different working conditions were carried out, and the results showed that the static strain time curve is viscoelastic and conforms well to the Bugers model, and the fitting coefficient of determination is 0.98. The strain response of the asphalt surface courses of the four pavement structures under static load shows a double hump variation with the transverse position, with peaks occurring directly beneath the wheel load center. The transverse strain fluctuated between tension and compression, mirroring changes in the lateral position. While longitudinal strains, always tensile, were symmetrically aligned with the centerline of the longitudinal sensors, this pattern differed notably from that of the transverse sensors. In the base layers, the strain profile typically presented a single peak, located at the wheel gap, underscoring a critical area of stress concentration. Numerically, the peak strain of asphalt surface course is larger than that of base course. The most unfavorable loading position of the base course occurs at the wheel gap of the lower base course. The most adverse loading position of the surface course appears at the wheel load at the bottom of the upper or middle course. The research results can provide data support for improving the design method of asphalt pavement.

Determination of dynamic collapse limit states using the energy-based method for multi-story RC frames subjected to column removal scenarios

The Alternative Load Path method is widely adopted to perform progressive collapse analyses for reinforced concrete (RC) frame structures subjected to column removal scenarios. Considering that the progressive collapses are usually dynamic phenomena, nonlinear dynamic analyses can yield the most accurate results. However, the associated computational cost is high. Alternatively, the energy-based method (EBM) can be employed to efficiently calculate the maximum dynamic responses. Unfortunately, collapse or dynamic limit states (DLS) cannot be directly determined when the EBM is adopted for the progressive collapse analyses, because it is essentially a quasi-static approach. To tackle this issue, in this paper an EBM-Intersection Point-based (EBM-IP-based) method is proposed to effectively determine the DLS. The method is considering that the dynamic instability will occur once the dynamic capacity curve exceeds the corresponding static capacity curve. Hence, it is possible to determine the DLS by making a correction on the intersection point of the aforementioned two curves without performing nonlinear dynamic time-history analyses. Compared with the other energy components, the kinetic energy at the moment of the peak displacement response is relatively small and the effectiveness of the EBM is verified. Through both static pushdown analyses and incremental dynamic analyses for 48 column removal scenarios of six different multi-story RC frames, the effectiveness of the proposed EBM-IP-based method is verified and the associated coefficients are calibrated. Statistical information and (joint) probabilistic density functions (PDF) of the coefficients are identified. Further, stochastic analyses are carried out in order to quantify the model uncertainties when adopting the EBM-IP-based method. On the basis of all the calculation results, a Gumbel distribution is adopted to capture the PDF of the model uncertainty in relation to displacements, while a lognormal distribution is adopted to fit the PDF of the model uncertainty in terms of resistances. Moreover, a multi-variate Gaussian distribution model with two components is employed to fit the joint PDF.

Mathematical Physics Analysis of Nozzle Shaping at the Gas Outlet from the Aperture to the Differentially Pumped Chamber in Environmental Scanning Electron Microscopy (ESEM).

A combination of experimental measurement preparations using pressure and temperature sensors in conjunction with the theory of one-dimensional isentropic flow and mathematical physics analyses is presented as a tool for analysis in this paper. Furthermore, the subsequent development of a nozzle for use in environmental electron microscopy between the specimen chamber and the differentially pumped chamber is described. Based on experimental measurements, an analysis of the impact of the nozzle shaping located behind the aperture on the character of the supersonic flow and the resulting dispersion of the electron beam passing through the differential pumped chamber is carried out on the determined pressure ratio using a combination of theory and mathematical physics analyses. The results show that nozzle shapes causing under-expanded gas outflow from the aperture to the nozzle have a worse impact on the dispersion of the primary electron beam. This is due to the flow velocity control. The controlled reduction in the static pressure curve on the primary electron beam path thus causes a significantly higher course of electron dispersion values than variants with shapes causing over-expanded gas outflow.

Preparation and Adsorption Performance of Boron Adsorbents Derived from Modified Waste Feathers.

This research focuses on modifying discarded feathers by grafting glycidyl methacrylate (GMA) onto their surface through thiolation, followed by an epoxy ring-opening reaction with N-methyl-D-glucamine (NMDG) to synthesize feather-based boron adsorbents. Optimization of the adsorbent preparation conditions was achieved through single-factor experiments, varying temperature, time, GMA concentration, and initiator dosage. The synthesized adsorbent (F-g-GMA-NMDG) underwent characterization using Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The adsorption behavior of the adsorbent was studied, and its boron adsorption capacity at different temperatures was determined through static adsorption kinetic curves. Analysis of adsorption isotherms, kinetics, and thermodynamics was conducted. Results indicate that the boron adsorption process by F-g-GMA-NMDG follows a pseudo-second-order model. The adsorption process is endothermic, with higher temperatures promoting adsorption efficiency. Gibbs free energy (ΔG) confirms the spontaneity of the adsorption process. Enhanced adsorption efficacy was observed under neutral and acidic pH conditions. After four cycles, the adsorbent maintained its adsorption efficiency, demonstrating its stability and potential for reuse. This study provides novel insights into both the treatment of discarded feathers and the development of boron adsorbents.

Synthesis, scale and corrosion inhibition evaluation and mechanism of 2-aminobenzimidazole modified polyaspartic acid

With the growing public concern for environmental preservation, this work employs environmentally friendly polyaspartic acid (PASP) as the main chain, to develop a green and efficient dual-function inhibitor with scale and corrosion inhibition. The new inhibitor PASP-2-A was synthesized by grafting 2-amino-benzimidazole (2-A) containing nitrogen heterocyclic into polysuccinimide under alkaline conditions. The corrosion inhibition of carbon steel and brass was determined by static test, polarization curve and electrochemical impedance spectroscopy (EIS). It can be found that PASP-2-A had better scale inhibition performance than PASP under different conditions. The addition of 5 mg·L−1 PASP-2-A can almost 100% prevent the formation of CaCO3 scale. Molecular dynamics simulation results showed that PASP-2-A significantly destroys the crystal structure of CaCO3 scale due to the coordination between PASP-2-A and Ca2+ groups. The modified PASP scale inhibitor can prevent the growth of calcite (110) and (104) crystal faces, regulate the transformation of CaCO3 from stable calcite to more soluble spherical vaterite, making it less deposit. The electrochemical test results showed that the corrosion inhibition of PASP-2-A is greatly improved compared with PASP, and the corrosion inhibition of Q235 carbon steel increased about 40% at the dosage of 200 ppm. The corrosion inhibition efficiency of H62 brass in 3.5 wt% NaCl was 97.97% with 300 ppm PASP-2-A. Notably, due to its degradable nature, low toxicity, and affordability, PASP-2-A serves as an excellent inhibitor, exhibiting remarkable performance in both scale inhibition and corrosion inhibition. Consequently, it presents a promising avenue for further advancements in modified PASP.

19 Evaluation of precision feeding standardized ileal digestible lysine to meet the requirements of lactating sows

Abstract Two experiments evaluated the effects of precision feeding lactating sows. In both experiments, sows were blocked by parity and allotted to treatment on d 2 of lactation. The first experiment included a total of 95 mixed parity sows and litters. Treatments included a control, NRC (2012), or INRA (2009) treatment curve. Sows on the NRC or INRA treatment curves received a blend of a low (0.25% SID Lys) and high (1.10% SID Lys) Lys diet using the Gestal Quattro Opti Feeder (Jyga Technologies, St-Lambert-de-Lauzon, Quebec, Canada) to target specific SID Lys intake/d based on parity and litter size according to NRC and INRA models. Control sows received only the high Lys diet. Blend of the high and low Lys diets were adjusted every 2 d based on actual Lys intake to more closely meet target Lys intake (NRC and INRA curves). Control sows had greater (P < 0.05) average Lys intake (76.7 g/d) compared with sows fed either NRC (53.1 g/d) or INRA (42.8 g/d) curves (Table). Pigs from sows fed the high Lys diet had greater (P < 0.05) body weight at weaning and average daily gain (ADG) compared with pigs from sows fed INRA treatment, with NRC curve fed sows intermediate. Nitrogen excretion, estimated from NRC equations, was greatest (P < 0.05) in sows fed the high Lys diet, followed by sows fed the NRC curve, and INRA curve sows the least. In Exp. 2, 56 mixed parity sows and litters were used. Treatments included a control where sows were provided a high Lys (1.10% SID Lys) diet and two treatments where sows were fed either a static or dynamic blend of a low (0.40 % SID Lys) and high Lys diet to target a specific SID Lys intake/d based on parity and litter size. The dynamic curve blend was adjusted based on actual Lys intake every 2 d to reach target Lys intake while the static curve was not adjusted. Lysine intake curves were based on the NRC (2012), but targets were increased by 20% to reach an average Lys intake of 60 g/d across parities. Control sows had greater Lys intake (P < 0.05; 77.7 g/d) compared with sows fed the blend curves, with no differences between the two blend curves (P > 0.05; 60.1 vs. 59.7 g/d). There were no differences (P > 0.05) observed in litter size, piglet or litter weight at weaning, or ADG. Estimated nitrogen excretion was greater (P < 0.05) for sows on the control diet compared with both blend curves. These data would suggest that 60 g/d of SID Lys is sufficient to maximize litter weight gain for litter sizes of 13.5 weaned piglets. Overall, feed blending can be used to decrease N excretion while achieving similar performance compared with feeding a standard high Lys diet.

Slope stability analysis based on rate-dependent soil-water characteristic curve

Rainfall-induced landslides are a common geological hazard. Analyzing this problem necessitates the use of the unsaturated soil theory, with the soil-water characteristic curve (SWCC) being a crucial component. Most existing unsaturated soil seepage models are established based on the static soil-water characteristic curve model. However, the dynamic capillary pressure has been observed in experiments conducted in previous studies. In this study, experiments were performed to explore the dynamic impact of the SWCC. The influence of different infiltration rates was studied, and a rate-dependent SWCC model under dynamic conditions was established. The model was validated through experiments. The behavior of an unsaturated soil slope under different rainfall intensities was analyzed based on the equivalent model. The equation for the slope safety factor was then derived using the Bishop method. The slope safety factors based on both the rate-independent and rate-dependent SWCC models were compared. The results indicated that the safety factor continuously decreased with increasing rainfall intensity. The dynamic effect reduced the safety factor, making the slope more susceptible to instability.

Frequency- and Temperature-Dependent Uncertainties in Hysteresis Measurements of a 3D-Printed FeSi wt6.5% Material.

Additive manufacturing of soft magnetic materials is a promising technology for creating topologically optimized electrical machines. High-performance electrical machines can be made from high-silicon-content FeSi alloys. Fe-6.5wt%Si material has exceptional magnetic properties; however, manufacturing this steel with the classical cold rolling methodology is not possible due to the brittleness of this material. Laser powder bed fusion technology (L-PBF) offers a solution to this problem. Finding the optimal printing parameters is a challenging task. Nevertheless, it is crucial to resolve the brittleness of the created materials so they can be used in commercial applications. The temperature dependence of magnetic hysteresis properties of Fe-6.5wt%Si materials is presented in this paper. The magnetic hysteresis properties were examined from 20 °C to 120 °C. The hysteresis measurements were made by a precision current generator-based hysteresis measurement tool, which uses fast Fourier transformation-based filtering techniques to increase the accuracy of the measurements. The details of the applied scalar hysteresis sensor and the measurement uncertainties were discussed first in the paper; then, three characteristic points of the static hysteresis curve of the ten L-PBF-manufactured identical toroidal cores were investigated and compared at different temperatures. These measurements show that, despite the volumetric ratio of the porosities being below 0.5%, the mean crack length in the samples is not significant for the examined samples. These small defects can cause a significant 5% decrement in some characteristic values of the examined hysteresis curve.

Electronic structure with spin-orbit coupling effect of HfH molecule for laser cooling investigations

The electronic structure, including the spin–orbit coupling effect of the HfH molecule, has been studied to determine if it can be cooled through Doppler and Sysphus laser cooling techniques. The multi-reference configuration interaction plus Davidson correction (MRCI + Q) method has been used to calculate its potential energy curves (P.E.C.s) in the Ω(±) and 2s+1Ʌ(+/-) representation. The spectroscopic constants Te, Re, ωe, Be, αe, the dipole moment µe, and the dissociation energies De agree very well with previously published work. In addition, we present in this work twenty new doublet and quartet states in the Ω(±) representation. The electronic transition dipole moment curves (TDMCs) between the lowest-lying electronic states have been investigated for the Δ - Π, Π - ∑+ and Δ - Φ transitions among specific Ω(±) states. The Franck-Condon factors (FCFs), the Einstein coefficient of spontaneous emission Aν′ν, and the radiative lifetime τ have been computed for the investigated transitions. In addition, properties of the molecules' electronic and vibrational states, such as the static dipole moment curves (D.M.C.s), the ionic character fionic, and the rovibrational constants are calculated. We deduce from our results that the HfH molecule is indeed a laser-cooling candidate that can reach a temperature as low as the nK regime. We present a complementary scheme with suitable experimental parameters. These results can be of great interest to experimental spectroscopists interested in ultracold diatomic molecules and their applications.

Study of operating modes of electromagnetic hammer with adjustable impact energy and blow frequency

The current work was designed to study the operating modes of electromagnetic impact mechanism (electromagnetic hammer) comprising idle and working stroke windings that are enclosed in magnetic conductor, and reciprocating ferromagnetic striker. Investigation was conducted by modelling in MATLAB environment and performing verification tests with different hammers. Simulation model of the hammer was derived using experimentally obtained static characteristic curves of flux linkage and thrust force for each of the windings. Results revealed that at maximum working stroke winding voltage-varying idle stroke winding voltage, the impact energy did not change, but the impact frequency varied between 0-187 bpm. At maximum idle stroke winding voltage and working stroke winding voltage ranging between 0 to maximum value, the impact energy varied between 84-360 J, the impact frequency varied between 96-187 bpm. Maximum losses over the working cycle were associated with electric losses in the hammer windings and can be reduced by reducing winding currents through increasing the striker speed. The mathematical model of the current study allowed quantifying energy parameters of the electromagnetic hammer. The impact machine cycle includes three operating modes, each determines the main energy parameters: efficiency, impact energy, and cycle time.

Conspicuous leisure, time allocation, and obesity Kuznets curves

Abstract Our growth model explores the complex relationship between income, obesity, and changes in exercise-related behavior. Combining Becker’s theory of time allocation (The Economic Journal 75(299), 493–517, 1965) with Veblen’s theory of conspicuous leisure (The Theory of the Leisure Class, 1st ed. New York: Macmillan, 1899), we determine conditions for dynamic and static obesity Kuznets curves. Considering food consumption and exercise choices, we show that dynamic and static Kuznets curves result from the rising opportunity cost of exercise and peer influence, both increasing with income. Focusing on calorie expenditure, we investigate the rise and slowdown in obesity prevalence in the USA and the correlation between obesity and income per worker. Our numerical simulations indicate that, as the economy grows, exercise choices slow down the rise in obesity prevalence but do not generate a dynamic Kuznets curve in the USA. By contrast, they generate a static Kuznets curve for a population cross section. We discuss policy implications of our findings.

Static term structure of interest rate construction with tension interpolation splines

<abstract><p>Traditional theories of term structure of interest rate consist of four major classical theories, including Pure Expectation Theory, Liquidity Preference Theory, Preferred Habitat Theory and Market Segmentation Theory. However, they cannot be well interpreted by the traditional static term structure of interest rate methods such as polynomial spline and exponential spline. To address problems on low precision and weak stability of traditional methods in constructing static interest rate term structure curve, in this paper, we introduce the tension interpolation spline based on a fourth-order differential equation with local tension parameters calculated by Generalized Reduced Gradient (GRG) algorithm. Our primary focus is to illustrate its better prediction effect and stability with an empirical study conducted using datum of treasury bonds. Then, we divided the datum into intra-sample datum for estimating tension parameters and out-of-sample datum for evaluating their robustness of predicting stochastics collected from Shanghai Stock Exchange on $ {2^{{\rm{nd}}}} $ February, 2019. According to the principle of total least squares and total least absolute deviations, the result shows that the tension interpolation spline model has better precision and stronger stability in prediction of out-of-sample treasury bonds prices compared with the model established by polynomial spline and exponential spline. In addition, it can better explain the Liquidity Preference Theory, which confirms that it is suitable for constructing the static term structure of interest rates in the securities exchange market.</p></abstract>

Acid Fracturing Technology and Effect Evaluation of Carbonate Horizontal Well in Fuman Oilfield

Since the deep and ultra-deep carbonate rocks in the Fuman oilfield have made continuous breakthroughs, the acidification and fracturing of the reservoir on the south bank of Tarim River have been faced with problems such as faster acidification and shorter effective acidification fracture length with the increased burial depth and formation temperature, which seriously restrict the effect of acidification and fracturing. At present, the Fuman oilfield has achieved remarkable results after acid fracturing construction. In this paper, the acid fracturing construction effects of multiple reservoir reconstruction Wells in Tahe Yueman, Fuyuan, Guole, and Manshen blocks are evaluated and classified by analyzing acid fracturing construction curves, using fracture static pressure fitting and fracture conductivity curve analysis. The characteristics and distribution law of carbonate reservoirs corresponding to different construction curves are studied, and various situations of artificial fractures communicating with natural fracture-cavity systems are analyzed. The research results can accurately guide the design optimization and development of acid pressure.

Electronic Structure Studies with Spin-Orbit Coupling Effect of the Molecule TlI

To study the low–lying electronic states of the TlI molecule, the electronic structure of this molecule has been investigated via an ab initio Complete Active Space Self Consistent Field and the Multireference Configuration Interaction with Davidson correction calculation (CASSCF/MRCI+Q). In the representations of 2s+1Λ(+/−) and (±), the adiabatic potential energy curves (PECs) along with static and transition dipole moment (DM) curves for 19 low-lying electronic states for TlI molecule have been investigated. For the low-lying electronic states of this molecule, the spectroscopic constants Re, Te, ωe, and Be, are provided. Based on the data obtained, this molecule is not a candidate for a Doppler laser cooling study.

Cyclic true stress true strain relation in the large strain region of common steel for welded structures

Cyclic true stress - true strain curves were obtained using general-purpose shipbuilding steel in the large strain region. Test methods are incremental step test and static tensile test after cyclic loading. The stress–strain curves for static and cyclic loading were compared to investigate the cause of the difference between each other. A simple method for estimating the cyclic stress-strain curves was proposed. The diameter and curvature of the smallest cross-section of the specimen were measured using telecentric measurement device, and the true stress - true strain curve was obtained using the Bridgman correction method. Using the measurement method, cyclic stress-strain diagrams were obtained in the region where the true strain exceeded 1% by performing cyclic tensile tests using the incremental step method and static tensile tests after cyclic loading. The influence of the test method and maximum displacement conditions on the cyclic stress-strain curve was small within the scope of this study. There was little difference in the elongation between the static tensile test and the static tensile test after cyclic loading. The difference in yield stress between static and cyclic loading was discussed in terms of macro-yield mechanisms at intergranular and transgranular. A simple method for estimating cyclic stress-strain curves from a static stress-strain curve was proposed. The specimens used in this study are general-purpose shipbuilding steels, and the results should be applicable to similar steels for welding and structures.