High Yield Point Research Articles

Mechanical behavior of powdered iron aluminide Fe – 28Al manufactured by direct powder forging

This study examines the impact of direct powder forging of powders on the composition, structure, and mechanical properties of iron aluminide Fe–28 at. % Al. During the synthesis and forging of Fe3Al powders, a homogeneous A2 phase is formed at a temperature of 1100 °C. Porosity after forging is 2–2.5 %. Residual pores are predominantly planar in shape and are located at the boundaries of the powder particles. Annealing at 1300 °C improves the quality of interparticle boundaries and all samples exhibit transcrystalline fracture mechanism. Samples forged at 1100 °C and annealed at 1300 °C show maximum strength σbend = 1050 MPa and fracture toughness K1c = 32.3 MPa·m1/2. The yield strength demonstrates anomalous temperature sensitivity with a maximum of 400 °C and at 500 °C. Samples tested at 600 °C show a decrease in yield strength, but a high enough yield point σy ∼400 MPa and a high strengthening rate are very important for high-temperature creep resistance. In creep experiments at a load of 120 MPa at 600 °C, the strain rate varies in the range of 10−7–10−6 s−1, the value of the rate sensitivity n ≈ 4. The main mechanism of creep is dislocation glide.

Study on the tensile behaviour and nano deformation mechanism of Nickel-based single crystal superalloys with γ/γ' structure at atomic scale

To study the deformation mechanism of nickel-based single crystal superalloys (NBSC) during tensile process, tensile experiments on NBSC are carried out by molecular dynamics to systematically analyze stress-strain, shear strain, atomic migration and defect evolution. The effects of the structure of the two phases and the strengthening elements on the tensile behavior are analyzed by comparing the pure Ni phase, the pure Ni3Al phase and the Ni phase containing the strengthening elements Cr and Co from a microscopic view. The results show that the interaction between the two-phase structural dislocations during tensile process balances the stress concentration and reduces the degree of plastic deformation that occurs within the matrix. The γ/γ' interface separates the strain morphology and inhibits the slip of the shear band between the two phases, resulting in enhanced deformation resistance of the matrix. By comparing the three single-phase structures, the γ/γ' structure has the highest yield point. From the shear strain distribution pattern, the portion of the two-phase structure with a larger degree of shear strain mainly occurs at the interface as well as at the edge of the matrix.

Fermented Rapeseed Meal as a Dietary Intervention to Improve Mineral Utilization and Bone Health in Weaned Piglets.

This study examined the effects of incorporating fermented rapeseed meal (FRSM) into the diet of newly weaned piglets on mineral digestibility and bone health. Experimental diets containing varying levels of FRSM (8%, 12%, 15%, and 25%) were introduced to the piglets at 18 days of age, prior to weaning at 28 days. These diets were continued until the piglets were euthanized at 42 days of age. Mineral absorption was assessed using the apparent total tract digestibility (ATTD) method and blood plasma element analysis, while bone mineral content and mechanical properties were evaluated through densitometry and three-point bending tests. The results showed that intermediate levels of FRSM (12-15%) significantly enhanced the digestibility of key minerals, including phosphorus, calcium, magnesium, copper, zinc, and iron. This improvement was linked to increased femoral mineral content and bone stiffness, as well as a higher yield point, likely due to enhanced collagen synthesis. Additionally, there was an increase in bone fracture load and fracture stress, potentially due to changes in the organization of the bone mineral phase, as no changes in bone mid-shaft mineral density or geometry were observed. These findings suggest FRSM as a promising dietary component for improving mineral bioavailability and bone health in piglets.

Bio-based unsaturated polyester resin from post-consumer PET.

This study explores the utilization of post-consumer poly(ethylene terephthalate) (PET) as a material in the synthesis of styrene-free unsaturated polyester (UP) resin. The process involves glycolysis of PET waste with diethylene glycol and condensation polymerization with bio-based itaconic acid. The resulting unsaturated polyester possesses reactive methylidene functions that, in contrast to commonly employed fumarates/maleates, facilitate copolymerization with non-styrene reactive diluents. To formulate the resins, methacrylates and itaconates were used for dilution, and the curing process is achieved through a redox initiation system at room temperature, followed by post-curing at elevated temperatures. The cured formulations were characterized by their glass transition temperature, determined by DMA analysis. Mechanical properties were evaluated using standardized tests in tension, flexure, and compression. Particularly promising characteristics are observed in formulations incorporating bio-based dimethyl itaconate (DMI), allowing the formulation of materials with a high ultimate flexural strength (σf,max = 161.4 MPa) and compressive yield point (σc,yield = 131.3 MPa). Furthermore, the low volatility of DMI addresses the health, safety, and ecological concerns associated with the commonly used styrene. This technology not only presents a promising avenue for sustainable UP resin for glass fiber reinforced composites but also allows upcycling PET waste.

Analysis of a drilling mud-based system on the common problems related to coiled tubing application in slim-hole oil wells

Coil tubing is slim and looks like a long, continuous length of pipe made from carbon steel metal that is a lesion on spool that is 1 to 3.25 inches in diameter of 26,000 feet long. The main benefit of coil tubing in drilling operations over wireline jobs is the ability to pump chemicals through the coil and the ability to push it into the hole rather than relying on gravity. Inappropriate selection of the drilling mud is one of the contributing factors to hole problems. Different experiments were conducted to determine the mud rheology of multiple mud samples. Certain parameters, like the critical velocity, are calculated using a numerical approach for the coiled tubing applications. In addition, it is crucial to determine the pump pressure required to maintain a specific flow rate. It is noted that drilling operations become more efficient at lower plastic viscosities; however, plastic viscosity is reduced through dilution; hence, the rate of penetration is improved. Moreover, a higher yield point is capable of transporting the cuttings more effectively than a lower yield point. The critical velocity indicated the boundaries between the laminar and turbulent flow regimes. As the mud flow rate inside the tubing increased, the velocity increased, causing the shear stress at the tubing wall to increase.

Biomechanical properties of splint materials while curing

Many studies have evaluated splint strength at maturity with multiple splint materials, methods, and configurations but none have analyzed splints as they cure. The purpose of this study is to evaluate the properties of different splint materials immediately following activation and as they mature.Splints were dipped for three seconds in two temperatures of water and an additional group of fiberglass with no water was tested as well. Splint weight was taken as an additional measurement to assure homogenous groups. All splints were tested in three-point bending at a constant displacement.The generalized linear model (GLM) including all time frames showed differences in yield load and ultimate loads after three minutes. All ultimate loads occurred at greater than 20° of angulation. Plaster had a much lower displacement at its yield load at all times after 3 min. Plaster had a higher stiffness at 1° of angulation at all time points after six minutes. The GLM that excluded the three-day time showed that the higher temperature increased initial stiffness in the splints at three and six minutes.Fiberglass has a higher yield point and ultimate load when compared to plaster. However, these loads were measured at significant splint angulation for the fiberglass, suggesting that plaster is acting as a true splint. Fiberglass is stronger and faster to cure than plaster. In situations where the surgeon desires the strongest splint, fiberglass may be preferable. However, the initial stiffness of plaster is superior to fiberglass.

Fatigue Properties of Spring Steels after Advanced Processing.

This article deals with the effect of strain-assisted tempering (SAT) on the fatigue properties of 54SiCr6 steel used for spring steel wires in a wide variety of automotive applications, including coil springs. This steel spring wire is extremely strong, having a high elastic limit and yield point, giving the steel excellent energy accumulation and fatigue properties. This combination opens up new possibilities in helical and cylindrical coil spring design, resulting in the reduction of both size and weight. Lightweight coil springs lead to improvements in fuel consumption, stability and vehicle traction. A large plastic deformation and SAT were applied to enhance the yield point of the study material. Improvements in the static and cyclic properties of steel springs were investigated using tensile tests and 3PB fatigue tests at ambient temperature. In addition, an advanced laser shock peening (LSP) process was employed to increase the fatigue resistance of the SAT material. The results presented here show great improvements in the static and fatigue properties over commercial steel treatment. The material quality of the wires was evaluated to be insufficient for further processing with cold coiling.

Clay-free biodiesel-based drilling fluid suitable for high temperature

This paper introduces the formation of a clay-free biodiesel-based drilling fluid system. The system uses the biodiesel derived from the transesterification between soybean oil and methanol as the continuous phase, which is environmentally friendly and has an appropriate flow state. In order to inhibit the hydrolysis of the base oil under high temperatures, a small amount of methanol is retained and Lime addition is minimized. Besides, the system also contains a special polyamine-typed rheological modifier instead of organoclay to provide a fragile gel-structure with lower plastic viscosity and higher yield point, thus good for hole cleaning and solid suspension while keeping a higher rate of penetration (ROP). In order to strengthen the plugging and fluid loss control abilities, superfine calcium carbonate and oxidized asphalt are added and obtain a good outcome. Evaluation results showed that the clay-free biodiesel-based drilling fluid exhibits good properties of rheology, filtration, and emulsion stability, with temperature resistance over 200°C, which is suitable for the exploration of unconventional oil/gas restores.

Seismic design and performance analysis of bridge bents retrofitted with multistage buckling-restrained braces

Buckling-restrained braces (BRBs) are often used to retrofit RC bridge bents to increase their strength and stiffness, and dissipate the seismic energy through hysteretic behavior. However, the post-yielding stiffness of BRBs is very low, and the total stiffness of the retrofitted bent drops sharply when the brace yields, which can lead to more serious damage to the primary structure contrary to the design purpose. Accordingly, multistage buckling-restrained braces (MSBRBs), consisting of steel cores with different yield strains, were used for the seismic retrofitting of bridge bents in this study. By controlling the low yield point (LYP) core yield before the bridge bents and high yield point (HYP) core yield after the bents, the expressions for the steel core length related to the geometric parameters of the bridge bents were derived. Furthermore, a preliminary seismic design method based on the structural fuse concept was proposed, which realized that the MSBRB dissipates energy while providing stable stiffness to improve the safety of the entire system. The advantages of the MSBRB in controlling the peak and residual displacement of the RC bent were proved via nonlinear time history analyses. Finally, the effects of the stiffness ratios, yield displacement ratios, and different configurations on the seismic performance of retrofitting bridge bents with MSBRBs were examined. The results showed that seismic performance of reinforced bents can be improved by increasing the stiffness ratio appropriately. The LYP core is primarily related to the energy dissipation capacity of the MSBRBs, and the value of βL should be less than 0.5. The HYP core is largely responsible for controlling the deformation of bridge bent, and βH must be greater than 1.0. Compared to other configurations, the diagonal MSBRB system has a greater energy dissipation capacity and higher seismic reduction rate.

Optimisation of Rheological Properties of Water-Based Mud (WBM) with Natural Additives by Using Response Surface Methodology (RSM)

The rheological properties of drilling muds are critical for achieving optimal performances during drilling operations. In this study, bentonite, tannin, and xanthan gum were utilised as water-based drilling mud additives to enhance the rheological properties. The Response Surface Methodology (RSM) with Box-Behnken Design (BBD) was used to investigate the additive's effect on the rheological properties of the drilling muds. The concentration of bentonite, tannin and xanthan gum were considered as the independent variables, while plastic viscosity (PV), apparent viscosity (AV), and yield point (YP) as the responses in the design of experiment (DOE). The YP, AV and PV were determined using 9.0 ppg of drilling mud according to the API standard procedures. Response surface plots (3D) were used to analyse the effect of the independent factors on the rheological properties and resulting in R2 values of 0.9753 for PV, 0.9582 for AV and 0.9513 for YP, which indicates that the interaction between elements in the system were statistically significant as these R2 values were close to 1.0. Bentonite was observed to significantly increased the PV, AV, and YP, whereas it decreased as tannin concentration increased. The optimal rheological properties required for low PV and AV with a high YP could be achieved using WBM formulation of bentonite at 4.02 g, 7.29 g of tannin, and 0.53 g of xanthan gum. Meanwhile, xanthan gum had an insignificant effect on the PV, AV, and YP. This finding demonstrates that the RSM model is accurate and relevant tool; hence it may be utilised to optimise the experimental conditions of mud formulation and accurately predict the rheology parameters of drilling muds.

Influence of Low Yield Point Reinforcement and High Toughness Concrete on Seismic Performance of the Frame

Currently, ordinary concrete and steel bars are mostly used in frames, but there is no systematic research on the impact of high toughness concrete and low yield point steel bars on the seismic performance of frames. The low-cycle repeated load test of three 1/3 ratio two-story and two-span cast-in-situ concrete frame specimens is carried out. The resilience model hysteresis characteristics, displacement ductility, and energy dissipation capacity are studied and analyzed by experiment. In addition, a comparative analysis is made between the ordinary frame and the frame with low yield point reinforcement. The restoring force model of reinforced concrete (RC) frame with low yield point reinforcement and high toughness concrete is given. The results show that the frame with low yield point reinforcement has better ductility and lateral stiffness than the ordinary reinforced concrete frame. The ductility of the frame will be improved by using high toughness concrete. The deformation ability of the members will be improved by using low yield point steel and high toughness concrete in the frame.

Plastic Deformation Simulation of REBCO Tapes Using Particle Methods

Ultra-high field superconducting magnets are facing a mechanical degradation problem. On 2017, a world-record high DC magnetic field of 45.5 T was generated by insert no-insulation (NI) Rare-Earth Barium Copper Oxide (REBCO) pancake coils (14.4 T), called “LBC3”, and an outsert resistive magnet (31.1 T). Although the experiment showed a high potential of the NI REBCO magnets for ultra-high field generation, the insert NI REBCO pancake coils and the REBCO tapes were plastically deformed. The critical current properties of damaged REBCO tapes were degraded although the Hastelloy substrate of REBCO tapes is stiff and it has a high yield point of approximately 1 GPa. However, the mechanisms of the damaging REBCO tapes are not clarified. Therefore, it is necessary to clarify the mechanical phenomenon of REBCO tapes. In this paper, we model a REBCO tape with a smoothed particle hydrodynamics (SPH) method, which can represent plastic deformation. The SPH simulation is coupled with electromagnetic analysis with a partial element equivalent circuit (PEEC) model which we have previously developed. In the simulation, an external field, which linearly increases to 5 T and then decreases to 0 T, is applied to a short-length REBCO tape. The simulation results show that the REBCO tape largely deforms during the external field excitation and deexcitation.

Probing the Damage Recovery Mechanism in Irradiated Stainless Steels Using In-Situ Microcantilever Bending Test

Single crystalline microcantilevers are fabricated from the base metal and heat-affected zone (HAZ) of a laser welded, neutron irradiated austenitic stainless steel, for scanning electron microscope (SEM) in-situ bending. In the HAZ, cantilevers exhibit higher yield point and lower crack tip blunting displacement than in the base metal and unirradiated archive specimen. These results suggest that radiation-induced defects harden the base metal, whereas the HAZ exhibits annealing of defects leading to mechanical softening. Dislocation nucleation ahead of the crack tip is responsible for ductile blunting behavior and provides a pathway to mitigating helium-induced cracking during weld repairs of irradiated materials.

Hybrid steel staggered truss frame (SSTF): A probabilistic spectral energy modification coefficient surface model for damage-control evaluation and performance insights

This paper attempted to quantify the inelastic seismic demand of hybrid steel staggered truss frame (SSTF) showing damage-control behaviour by using a probabilistic seismic demand spectral surface model. The study was commenced by developing the idea of hybrid SSTF composed of high strength steel members and low yield point steel dampers. In order to evaluate the structural damage-control behaviour, inelastic spectral energy modification coefficient surfaces were developed based on the single-degree-of-freedom (SDOF) analogy with bilinear kinematic hysteretic law. According to the statistical characteristics of the analysis data pool, it was found that the spectral energy modification coefficient followed a positively skewed probabilistic distribution. The energy modification coefficient surfaces were appreciably affected by structural parameters and statistical features of earthquake motions. Then, empirical expressions of the energy modification coefficient surfaces considering the influence of essential parameters were established. Based on previous experimental data, the finite element modelling techniques for developing a hybrid SSTF were verified. Cyclic pushover analysis and nonlinear response history analysis (NLRHA) of a prototype structure revealed that the hybrid SSTF showed favourable damage-control behaviour by concentrating inelastic actions in low yield point steel dampers. The insignificant post-earthquake residual deformations were also characterised. The adequacy of the proposed spectral energy modification coefficient surface model for evaluating the damage-control behaviour of hybrid SSTF was confirmed by NLRHA of the prototype structure.

Hybrid Welding (Laser-Electric Arc MAG) of High Yield Point Steel S960QL.

The article discusses the effect of the hybrid-welding process (laser–electric arc MAG Metal Active Gas) on the structure and properties of butt joints (having various thicknesses, i.e., 5 mm and 7 mm) made of steel S960QL. Welding tests were performed in the flat position (PA) and in the horizontal position (PC). Joints made of steel S960QL in the above-presented configuration are present in elements of crane structures (e.g., telescopic crane jibs). The welding tests involved the use of the G Mn4Ni1.5CrMo solid electrode wire and the Ar+18% CO2 shielding gas mixture (M21) (used in the MAG method). Non-destructive visual and radiographic tests did not reveal the presence of any welding imperfections in the joints. The welded joints obtained in the tests represented quality level B in accordance with the requirements of the ISO 12932 standard. Microscopic metallographic tests revealed that the heat-affected zone (HAZ) contained the coarse-grained martensitic structure resulting from the effect of the complex welding thermal cycle on the microstructure of the joints. Destructive tests revealed that the joints were characterised by tensile strength similar to that of the base material. The hybrid welding (laser–MAG) of steel S960QL enabled the obtainment of joints characterised by favourable plastic properties and impact energy exceeding 27 J. The tests revealed the possibility of making hybrid-welded joints satisfying the quality-related requirements specified in the ISO 15614-14 standard.

In vitro behavior of bioactive hybrid implant composed of additively manufactured titanium alloy lattice infiltrated with Mg-based alloy

We have developed a novel bioactive hybrid metallic implant that integrates the beneficial characteristics of a permanent matrix and a biodegradable substance. Such a combination may generate a material system that evolves into a porous structure within weeks to months following implantation and can be used to form strong interfacial bonding and osseointegration for orthopedic and dental applications. Presently, traditional technologies such as casting, powder metallurgy and plastic forming have limited ability to produce the complex bioactive implant structures that are required in practical applications. The present study aimed to develop an innovative bioactive TiMg (BTiMg) hybrid system using a Ti-lattice (Ti-6Al-4 V) produced by an additive manufacturing (AM) process, in combination with a new Mg-based alloy (Mg-2.4%Nd −0.6%Y -0.3%Zr) as a biodegradable filling material. We evaluated the in-vitro behavior of the BTiMg system in a simulated physiological environment, along with cytotoxicity assessment. The microstructure was evaluated by scanning electron microscopy and X-ray diffraction, mechanical properties were examined in terms of compressive strength, environmental performance analysis was conducted by electrochemical testing using potentiodynamic polarization and impedance spectroscopy (EIS), and cytotoxicity characteristics were assessed by indirect cell viability analysis. The results demonstrated the feasibility to produce geometrically complex implants by AM technology, as well as the strength and non-cytotoxic effects of the BTiMg system. Benefits included a relatively high ultimate compressive strength (UCS) and a high yield point (YP), along with an adequate cell viability response in the range between 70 and 120%.

Extracting true stresses and strains from nominal stresses and strains in tensile testing

AbstractSeemingly a simple task, the extraction of the flow curve (true stress vs. true plastic strain) from nominal stresses and strains in standard tensile testing still has its unsolved points. This study addresses two of them: (i) in materials without yield point phenomenon (or generally in the region of homogeneous plastic deformation), the true stress is typically calculated assuming constant volume, ignoring the elastic volume changes. Here, we derive a set of exact analytical solutions for true stresses and strains with remarkable simplicity and beauty that fully account for the elastic volume changes. This set of exact solutions is cross‐checked by finite element simulations as well as zeroth‐ and first‐order approximations; perfect agreement has been found. (ii) In materials with a pronounced yield point phenomenon, a complicated three‐dimensional stress state inevitably arises at the edge of the Lüders bands, which masks the real (or inherent) material behaviour. To determine the real material behaviour in the Lüders region, here we use a new macroscopic analytical approach characterised by a high true upper yield point, a typical strain hardening behaviour common for many materials, and the triaxiality of the stress state that inevitably develops at the edges of the Lüders bands and that determines the stress level at the observed lower yield point. This approach is verified by experiments (including video observations as well as digital image correlation (DIC) strain distribution measurements) and finite element simulations with very good agreement.

Rheological behaviour of water based mud formulated with sodium hydroxide (NaOH) plant extracts

The rheological behaviour of drilling mud formulated with sodium hydroxide extracts of Bitter-leaf (BL), Pawpaw (PL), Almond (AL) and Moringa (ML) leaves applied as surfactant (emulsifiers) was studied. The rheological properties (plastic viscosity (PV), yield point (YP), and gel strength) of the mud were measured using standard procedures. The mud specific gravity for BLEM and PLEM was observed to give same value (1.08) as that of the C1 mud. pH of the formulated mud were all alkaline and in the order BLEM (8.6) > PLEM (8.3) > ALEM (8.3) > C1(8.3) > MLEM (8.2) > C2 (8.2). The highest PV (19cP) was recorded by PLEM at 30ºC, while the least value (6cP) was by C2 at 60ºC temperatures. Highest YP (70 1b/100ft2) was recorded by C2 while the lowest YP value (22 1b/100ft2) by C1 both at 30ºC. Gel strength at 10 seconds showed reduction in value as the temperature increased for MLEM, ALEM, C2 and C1 formulated mud and recorded maximum of 45 1b/100 ft2 at 30ºC for C2 while the lowest gel strength was reported by C1 at 60ºC. The results obtained from the study showed that the various alkaline plant extracts used as emulsifying agent have no negative effect on the rheological properties of the formulated mud, rather it enhances the rheological properties even after aging of the mud at 65oC. These results therefore, show the need to use the various plant extracts as alternative additive (emulsifying agent) in the formulation of water based drilling mud.

Growth and Yield of Onion as Influenced by Sulphur and Boron with Mulch Materials

A field experiment was conducted at the research farm of Sher-e-Bangla Agricultural University, Dhaka. During the period from October, 2018 to March, 2019 to find out the growth and yield of onion as influenced by Sulphur and Boron with mulch materials. The experiment consisted of two factors: Factor A: Four doses of Sulphurand Boron fertilizer viz. F0 = S0kgB0kg/ha (Control), F1 = S20kgB1kg/ha, F2 = S40kgB2kg/ha, F3 = S60kgB3kg/ha and Factor B: Four types of mulch viz. M0 = No mulch and no irrigation, M1 = Black polythene, M2 = Water hyacinth and M3 = Rice straw. There were 16 treatment combinations and experiment was setup in a Randomized Complete Block Design (RCBD) with three replications. In case of Sulphur and Boron treatments at 60 days after transplanting (DAT), the highest plant height 53.38 cm, maximum leaf number 10.48, highest bulb length 4.83 cm,, maximum neck diameter (1.31 cm), highest dry matter content (15.98%), dry matter content of leaf (24.74%), single bulb weight (39.93 g), yield per plot (0.80 kg) and yield per hectare (9.98 t) were obtained from F3 treatment. Among the mulch materials, highest plant height at 60 DAT (52.51 cm), maximum leaf number (10.19), highest bulb length (4.52 cm), highest bulb diameter (5.74 cm), maximum neck diameter (1.26 cm), dry matter content of leaf (23.35%), single bulb weight (39.05 g), yield per plot (0.78 kg) and yield per hectare (9.76 t) were obtained from M1 treatment. In combined effect, the highest plant height at 60 DAT (55.54 cm), maximum leaf number (11.47), longest bulb length (5.51 cm), highest bulb diameter (6.68 cm), maximum diameter of neck (1.42 cm), dry matter content of leaf (27.48%), single bulb weight (42.40 g), yield per plot (0.85 kg) and yield per hectare (11.21 t) were obtained from F3M1 treatment (S60kg/ha + B3kg/ha with black polythene mulch). The highest gross return (Tk. 3, 36, 300/ha), net return (Tk. 1, 88, 934/ha) and benefit cost ration (2.28) was obtained from the treatment combination (F3M1). Accordingly, for high growth, high yield, and economic point of view, F3M1 treatment is recommended in onion cultivation.

A finite element method based on modified Alonso unsaturated soil constitutive model

Based on the revised ALONSO model, combined with the ABAQUS software platform, this paper compiled the USDFLD subroutine and obtained the stress-strain curve and the axial strain-volume deformation by simulating the triaxial shear test of the unsaturated soil to control the suction and confining pressure. The curve verifies the accuracy and reliability of the algorithm. The research results show that: (1) When the suction is the same, the higher the confining pressure is, the higher the yield point of the soil sample is. According to the comparison between experiment and simulation, the modified Alonso model can reflect the nonlinearity of the stress-strain relationship of the reshaped unsaturated soil sample and its plastic flow characteristics; (2) Compared with saturated soil, unsaturated soil has a higher yield point as a result of the suction. And the larger the suction is, the higher the yield point is, which proves that the model can simulate the influence of unsaturated soil liquid relative to the solid phase.