Test Temperature Research Articles

A Phenomenological Model for Creep and Creep-Fatigue Crack Growth Rate Behavior in Ferritic Steels

A model to rationalize the effects of test temperature and microstructural variables on the creep crack growth (CCG) and creep-fatigue crack growth (CFCG) rates in ferritic steels is described. The model predicts that as the average spacing between grain boundary particles that initiate creep cavities decrease, the CCG and CFCG rates increase. Further, the CCG data at several temperatures collapse into a single trend when a temperature compensated CCG rate derived from the model is used. The CCG and CFCG behavior measured at different temperatures is used to assess the effects of variables such as the differences between the base metal (BM), weld metal (WM), and heat-affected zone (HAZ) regions. The model is demonstrated for Grade 22 and Grade 91 steels using data from literature. It is shown that differences between the CCG behavior of the Grade 22 steel in new and ex-service conditions are negligible in the BM and WM regions but not in the HAZ region. The CCG behavior of the Grade 91 steels can be separated into creep-ductile and creep-brittle regions. The creep-brittle tendency is linked to the presence of excess trace element concentrations in the material chemistry. Significant differences found in the CCG rates between the BM, WM, and HAZ regions of the Grade 91 steel are explained.

Influence of temperature on deformation and damage mechanisms of wire + arc additively manufactured 2219 aluminum alloy

This work investigates the deformation and damage mechanisms of wire + arc additive manufacturing (WAAM) 2219 aluminum alloy over a broad temperature range of 77 K to 523 K. It is found that the strength and work hardening rate increase significantly with decreasing the temperature from 523 K to 77 K, and the fracture mode transitions from transgranular fracture mode to a mixture of intergranular and transgranular fracture ones. The large elongations to fracture are very similar for the specimens tested at 77 K and 523 K. This is mainly attributed to higher uniform elongation before necking at 77 K and higher post-necking elongation at 523 K. The cracking of α-Al + θ (Al2Cu) eutectics is the primary mechanism of micro-void nucleation, independent of the test temperature. The nucleated micro-voids, along with larger gas pore defects introduced by WAAM, extend along the tensile direction. In addition, as the temperature increases from 77 K to 523 K, the fracture mechanism transitions from high strain localization to extensive necking, leading to higher dislocation density, more grain fragmentation and micro-void nucleation, and more significant grain elongation and void growth. True stress and strain responses over the studied temperature range (77 ∼ 523 K) and strain rate range (0.0001 ∼ 0.01 s−1) are well predicted using an improved Arrhenius-type constitutive model, by considering the activation energy of deformation as a function of temperature.

Prediction and demonstration of periodic tensile cracking in rate-dependent porous cement

Periodic tensile cracks are shown to occur when cylinder-shaped saturated cement specimens are subjected to rapid decompression, with the spacing between the cracks scaling as a power law of the decompression time. This behavior is predicted by theory, which is specified to this scenario based on prior work that was more general and applied to compaction bands. Specifically, the formation of the tensile cracks is shown to coincide with periodicity that naturally arises in the effective stress when the material follows a Terzaghi-type consolidation law, although in reverse for dilation and with material deformation described by a rate-dependent viscoplastic law. When strain rate is proportional to effective stress to a power that is greater than one, periodic regions of tensile effective stress arise through the poromechanical fluid–solid coupling. The theoretically-predicted exponent of the resulting power-law relationship between tensile cracks spacing and unloading time successfully brackets the experimental results, for which it is observed that the exponent is slightly stronger than a square-root relationship (0.28 to 0.67) at testing temperatures of 20 ℃ and 90 ℃. These results demonstrate that rapid-depressurization leads to periodic fracturing that could, on the one hand, be detrimental to the isolation provided by cement used to seal wellbores in the petroleum industry. On the other hand, the periodic tensile cracks could also be favorable to production if generated in low-permeability reservoir rocks such as shales that are targeted for petroleum production or granites that are targeted for geothermal energy.

The effect of SPS sintering temperatures on the structure, thermoelectric properties, and scattering mechanism of Cu2Se

Cu2Se has recently received much attention due to its excellent thermal and electrical transmission characteristics. In this study, Cu2Se compounds were synthesized by vacuum melt-annealing method and sintered by discharge plasma sintering (SPS) in the 793–1093 K temperature range. The effects of SPS temperatures of 793, 893, 993, and 1093 K on the phase composition, microstructure, band structure, and thermoelectric properties of Cu2Se samples, as well as the test stability of Cu2Se at high temperatures were studied. The results show that the sintering temperature affects the thermoelectric properties, microstructure, and energy band structure of Cu2Se compounds. The samples show many component segregations with nano-micron size and irregular morphology. According to conductance ratio analysis, the primary mechanism of carrier scattering is ionized impurity scattering, consistent with the change of carrier mobility with the test temperature. Combined with the XPS analysis results and defect balance equation, the mechanism of the test temperature depends on carrier concentration, and the carrier scattering mechanism is reasonably explain. The lattice thermal conductivity of Cu2Se materials is relatively low at all sintering temperatures due to nano-micron segregation and the presence of high-mobility Cu ions. Especially at the sintering temperature of 893 K, the segregation of nano-micron components is the most uniform, and the segregation particle size is the smallest, effectively enhancing the phonon scattering and making the lattice thermal conductivity the lowest. At 873 K, the ZT of Cu2Se sintered at 893 K reaches a maximum value of 1.34.

Influence of 0.5% Ag Addition on Low-Cycle Fatigue Behavior of Hot-Extruded Al-5Cu-0.8Mg-0.15Zr-0.2Sc Alloy Subjected to Peak-Aging Treatment

The total strain amplitude controlled low-cycle fatigue tests were performed at room temperature and 200 °C to clarify the influence of 0.5% Ag addition on the low-cycle fatigue behavior of an Al-5Cu-0.8Mg-0.15Zr-0.2Sc (in wt.%) alloy subjected to the peak-aging treatment after hot extrusion and solid solution treatment. The experimental results demonstrate that during low-cycle fatigue deformation, peak-aged Al-5Cu-0.8Mg-0.15Zr-0.2Sc(-0.5Ag) alloys exhibit cyclic hardening, cyclic stability, or cyclic hardening followed by cyclic stability, depending on the Ag addition, imposed total strain amplitude, and testing temperature. The addition of 0.5% Ag greatly increases the low-cycle fatigue life of peak-aged Al-5Cu-0.8Mg-0.15Zr-0.2Sc alloy, where the maximum rising amplitude is about 126.7% at ambient temperature and approximately 90.1% at 200 °C. Furthermore, it has been discovered that the addition of 0.5% Ag has no effect on the beginning and spreading modes of low-cycle fatigue fractures. For the peak-aged Al-5Cu-0.8Mg-0.15Zr-0.2Sc(-0.5Ag) alloys subjected to low-cycle fatigue deformation at different total strain amplitudes and testing temperatures used in this investigation, fatigue cracks initiate trans granularly at the free surface of the fatigue specimen and propagate in a trans granular mode.

Microstructural features and hot tensile behaviour of tungsten inert gas welded TP321 nuclear tubes at elevated temperatures

Austenitic stainless steel (ASS) tubes, specifically TP321, are widely used in nuclear reactors and heat exchangers due to their excellent strength, toughness, and corrosion at ambient and elevated temperatures. The microstructure observed in the TP321 weldment reveals the existence of equiaxed dendrites, along with delta ferrite and TiC precipitates within the austenitic matrix. Electron backscatter diffraction (EBSD) scans confirm differences in texture, grain size, and grain misorientation distribution in the weld metal (WM), heat-affected zone (HAZ), and base metal (BM) regions of the weldment. The EBSD texture at the WM zone is strong in the 〈0 0 1〉 fiber direction, consistent with the face-centered cubic structure of the TP321. Hot tensile tests were conducted on BM and WM samples at 450 °C, 550 °C, 650 °C, 700 °C, 850 °C, and 900 °C using a Gleeble 3500 simulator. The yield strength (YS), ultimate tensile strength (UTS), and percentage elongation (EL) exhibited a decreasing trend with the rise in test temperature. The strain hardening capacity (Hc) of both BM and WM decreases with increasing test temperatures due to enhanced dislocation movement. The strain hardening exponent, ‘n’ was determined for BM and WM through suitable fitting of stress–strain curves using the Hollomon equation and depicted a decreasing trend with rising test temperatures. The fractured samples are subjected to scanning electron microscope (SEM) analysis to investigate the failure mechanism. Fractography of the fractured samples reveal the presence of micro voids and dimples, supporting the ductile nature of the rupture.

High-Temperature Mechanical Behavior of an As-Extruded Al-5Zn-2Mg-0.3Cu (in wt.%) Alloy

To ensure that Al alloys are being served as the high-temperature structural components for applications in aerospace and transportation, it is necessary to investigate their high-temperature mechanical behavior and failure mechanism. In this paper, the mechanical behavior of the as-extruded Al-5Zn-2Mg-0.3Cu (in wt.%) alloy was studied and compared under different high-temperature tensile-testing conditions. It was found that the yield strength and the ultimate tensile strength of the alloy gradually decreased with the increase in temperature, but its elongation ratio showed a slightly increasing trend. Failure analysis demonstrated that there were a lot of ductile dimples on the fracture surfaces and that obvious necking occurred for the samples being tensile-tested at different temperatures. Surface observation revealed that the initiation of micro-cracks was mainly attributed to the self-cracking of the brittle phase particles. Moreover, when the testing temperature was between 450 °C and 550 °C, micro-cracks could also occur at the interface between phase particles and the Al matrix.

Evaluation of quantum dot composite graphene /Titanium oxide enhanced UV aging resistance modified asphalt

The long-term ultraviolet radiation of asphalt pavement leads to performance degradation, which seriously affects the service life. However, inorganic nanoparticles as anti-ultraviolet aging modifiers can only respond to some ultraviolet light, resulting in not high absorption rate of ultraviolet light. In this study, a variety of nano-quantum dots were introduced to modify graphene/titanium dioxide to further improve the ultraviolet absorption capacity of inorganic nanoparticles and slow down the aging of asphalt pavement caused by ultraviolet light. The effect and mechanism of the special heterojunction structure formed by a variety of quantum dots on the aging resistance and rheological properties of asphalt were investigated. The results show that the introduction of various quantum dots improves the ultraviolet absorption capacity of nano-TiO2. Although the thermal stability of nanographene/titanium dioxide composites decreases, its initial decomposition temperature is much higher than the test temperature of the asphalt mixture. From the macroscopic rheological test, the nano-graphene / titanium dioxide composite material further expands the improvement effect on the high-temperature rheological properties of asphalt, and secondly slows down the low-temperature crack resistance of nano-TiO2 modified asphalt. From the microscopic test, the introduction of various quantum dots greatly reduces the sulfoxide index (SI), carbonyl index (CI) and root mean square roughness Sq of modified asphalt, effectively slowing down the aging effect of ultraviolet light on asphalt, and ensuring the service state of asphalt pavement in a complex environment.

Synthesis and performance evaluation of multi-crosslinked preformed particle gels with ultra-high strength and high-temperature and high-salinity resistance for conformance control

Preformed particle gels (PPGs) have been identified as an effective method to control conformance and mitigate excessive water production. However, the weak strength of swollen PPGs makes them susceptible to shear failure during formation migration in harsh reservoir conditions. To address this issue, a novel type of multi-crosslinked preformed particle gels (MC-PPGs) with ultra-high strength, exceptional temperature and salinity resistance has been developed. Vinyl silica nanoparticles (VSNPs) were first prepared and used as nano crosslinking agents and enhancing agents in constructing multiple cross-linking structures with macromolecules, functional monomers, and crosslinking agents. MC-PPGs have an elastic modulus up to 110,000 Pa, which is significantly higher than other existing PPGs. Additionally, when exposed to high-salinity environments (e.g., 20 % NaCl and 10 % CaCl2 + 10 % MgCl2), MC-PPGs remain for an extended period at elevated temperatures (80 °C for 24 months, 120 °C for 13 months, and over one month at 160 °C). Furthermore, the degradation products of MC-PPGs have minimal impact to reservoir permeability, with a core damage rate below 5 %. MC-PPGs are pH-adaptable (1 < pH < 12), which makes them a promising candidate for reservoirs with supercritical CO2 flooding. Laboratory coreflooding tests have demonstrated that MC-PPGs provide excellent plugging efficiency (>99.9 %) for fractured cores and ultra-high breakthrough pressure gradients (>14 MPa/m) at varying test temperatures (20 °C, 80 °C, and 120 °C). Considering these unique features, MC-PPGs are ideally suited for oilfield applications.

The thermoplastic polyurethane coated-LZH nanohybrids as a strategy for epoxy resin flame retardancy

Over traditional flame retardants, the hybrid material technology of flame retardant combines separate constituents into an entirety, demonstrating the benefit of the simultaneous development in polymer flame retardant. Zinc-layered hydroxide, borate, and thermoplastic polyurethane were used to create LZH/B/TU, a new organic-inorganic composite flame retardant. The structure of LZH, LZH/B, and LZH/B/TU was studied after synthesis with analysis spectroscopy. The borate ion was effectively intercalated into the interlayer space of the LZH, according to the XRD and FTIR studies. Using EDS analysis, the chemical makeup of the materials was assessed. The morphology of the synthesized product was identified using FESEM. The dynamic mechanical thermal (DMT) properties of the optimum sample were evaluated with DMTA analysis. The fire risk of epoxy resin was considerably reduced by using a small amount of LZH/B/TU. According to the flammability test and plate temperature experiment, LZH/B/TU with 1% w/w led to the creation of the char layer’s capacity to insulate heat with strong thermal resistance, resulting in dramatically reduced fire hazards.

Fatigue and Fracture Behaviors of Short Carbon Fiber Reinforced Squeeze Cast AZ91 at 20 °C and 250 °C

AZ91 is one of the most broadly used Mg alloys because of its good castability and reasonable mechanical properties. Strengthening AZ91 with carbon short fibers aims to increase tensile and fatigue strength, creep, and wear resistance. One of the proposed applications of reinforced AZ91 is the production of pistons for trucks. Such reciprocating parts are subjected to alternating fatigue loads which can lead to fatigue failure. In this respect, studying the tensile and fatigue behavior of materials subjected to such loading conditions is of great interest. The alternating low-cycle fatigue (LCF) and high-cycle fatigue (HCF) of unreinforced AZ91 and carbon fiber-reinforced AZ91 (AZ91-C) were investigated at 20 °C and 250 °C. Tensile tests were carried out at the same testing temperature to find the appropriate fatigue testing stress and strain for stress-controlled and strain-controlled tests, respectively. The fatigue curves of stress against the number of cycles (S–N) revealed that the composite AZ91-C’s fatigue strength was 55 MPa under HCF, while that of the matrix alloy AZ91 was only 37 MPa at 250 °C. Fracture investigations were conducted on the broken test samples. The fracture approach in the matrix material (AZ91) is mixed ductile/brittle containing fatigue serration, fiber fracture, and separation in the reinforced material (AZ91-C).

Experimental study of shape memory alloy plates under cyclic tension–compression loading scenarios

Shape memory alloys (SMAs) have garnered significant attention for their potential in earthquake-resistant structures, primarily due to their superelastic effect and exceptional self-centring capabilities. However, the mechanical properties of SMA plates, especially under cyclic tension–compression loading, remain underexplored. This research aims to bridge this gap by designing and testing 33 SMA plates equipped with buckling-restrained devices. The study varied parameters such as specimen thickness (4 mm, 6 mm, and 8 mm), loading protocols (seven in total), and test temperatures (25 °C and 0 °C). The findings reveal that the stress–strain curves under cyclic tension–compression loading exhibited asymmetric characteristics. For instance, at 25℃, a 4 mm thick specimen at 4% strain had a compressive peak stress that was 22.2% higher than its tensile counterpart, and its compressive residual strain exceeded the tensile residual strain by 99.0%. Furthermore, when compared to SMA plates under cyclic tension-release loading, those under cyclic tension–compression loading had reduced tensile residual strains. At 0 °C, the peak stress saw a decrease ranging from 2.4 to 43.1%, while the residual strain surged by 11.9–591.4% compared to the tests at 25℃. This study provides novel insights into the behavior of SMA plates under varied conditions, emphasizing their potential for seismic applications.

Uniform moduli characterization of asphalt mixtures under dynamic and static loading conditions

The modulus is a crucial material parameter reflecting stiffness characteristics of asphalt mixture in the elastic stage. Under specific conditions such as identical temperatures, loading velocities, and stress amplitudes, the moduli under the same stress state are theoretically identical. However, the moduli were artificially divided into dynamic moduli and static moduli based on loading methods during test, which brought uncertainties and disunity for estimating the stiffness performance of asphalt mixture. In this study, the dynamic and static moduli under distinct temperatures, loading velocities, and stress states were measured. The relationship between dynamic and static moduli was established by applying loading velocities as independent variable and moduli as the dependent variable. Through Sigmoidal function and WLF function fitting, the uniform characterization master curves of dynamic and static moduli under distinct temperatures, loading velocities, and stress states were established. The moduli of asphalt mixture under distinct test temperatures, loading velocities, and stress states can be obtained by the models, which provide material parameters for mechanical response analysis of asphalt pavements under distinct service environments. This resolves the issue of inconsistent moduli parameter selection.

Test Method of Secure and Controllable FPGA Chip Used in Flexible DC Transmission Control and Protection System

Flexible DC transmission control and protection system is a high-performance distributed computing system, which has the characteristics of high-speed data acquisition and fast processing, and uses a large number of high-performance FPGA (Field Programmable Logic Array) chips. FPGA has the characteristics of high integration and complex manufacturing process, and its security and controllability is faced with many challenges. The reliability of FPGA is an important standard to measure its performance, so reliability test fault screening is very important to ensure its normal operation. Although the automatic test equipment (ATE) can test the fault of FPGA, it is not convenient for field testing due to the price, test environment and other factors. In this paper, a design scheme of built-in self-test (BIST) for fault detection and fault diagnosis is proposed, which can detect faults of look-up table (LUT) and interconnection resources (wires and programmable switches). At the same time, considering the effect of rising temperature on fault probability, a controlled self-heating element (SHE) is constructed by using the internal resources of FPGA to provide the required temperature for BIST testing. Finally, an integrated layout scheme of BIST and SHE is proposed. An experiment of self-heating of FPGA chip is completed by TSINGHUA PGL22G, which verifies the correctness and feasibility of the theory.

Metallic Honeycomb Catalysts for Methane Steam Reforming: Effect of the Bimetallic Surface Coating on Catalytic Properties

Metallic honeycomb catalysts are promising candidates for fuel cell and small-scale onsite hydrogen production applications. In this study, high-cell-density Ni honeycomb catalysts coated with a series of bimetallic surface layers were synthesized. Their catalytic performance for CH4 steam reforming was investigated under a low steam-to-carbon ratio of 1.36 and a gas hourly space velocity of 6400 h-1 in the temperature range of 400–700°C. The catalysts coated with Ni-Mg and Ni-Zr showed excellent catalytic performance, reaching a high CH4 conversion and CO selectivity close to the equilibrium values within the test temperature range. The enhanced catalytic performance of the Ni-Mg and Ni-Zr coatings was attributed to the formation of oxide-supported fine Ni particles. In contrast, the catalysts coated with Ni-Fe and Ni-Sn exhibited an extremely low activity, which was lower than that of the catalyst coated with only Ni. The low activity of the Ni-Fe and Ni-Sn coatings is supposed to be due to the formation of aggregated Ni3Fe, Ni3Sn, and Ni3Sn2 phases.

Enhanced size effects on shear performance and fracture behavior of BGA structure micro-scale Cu/Sn–3.0Ag–0.5Cu/Cu joints at low temperatures

To assess the serving reliability of shrinking-sized solder joints in space electronics (especially cryogenic electronics), the effects of joint size on the shear performance of Cu/Sn–3.0Ag–0.5Cu/Cu joints with ball grid array (BGA) structure at different temperatures (25 to −125 °C) were investigated. As the joint size decreased, shear strength of the solder joint increased, showing prominent size effect, which was enhanced at low temperatures. Moreover, a ductile-to-brittle transition (DBT) fracture occurred as the test temperature declined, and the critical temperature decreased as the joint size decreased. All of the results suggest that the small-sized joints are more robust at low temperatures under shear loading.

Визначення здатності до дисперсійного твердіння нової штампової сталі з регульованим аустенітним перетворенням

The chemical composition of the stamping steel for high operating temperatures (above 700 °C) with controlled austenitic transformation during operation (CATO) was adjusted to implement its hardening by the dispersion hardening (aging) mechanism. The base steel was chosen as 3Х3Н8М7Ф, in which quenching and subsequent aging did not lead to such hardening. It was taken into account that in order to implement dispersion hardening, CATO steels should have a predominantly austenitic (rather than martensitic) structure in the hardened state, which was not provided for the base steel. As a result of changes in the content of Mn, Ni and C in the base steel, it was determined that the required conditions are met by CATO steel of grade 4Х3Н3Г6М7Ф (95 % austenite after quenching with a predominantly ferrite base in the annealed state). The experiments have established the ability of this steel to harden with ageing. Strength growth was determined by high-temperature tensile tests immediately after aging (without intermediate cooling of samples to room temperature), which is a feature of testing steels with CATO. The highest strength growth (compared to the quenched state) is provided by heat treatment in the following mode: quenching 1150 °C, 2 hours, oil and subsequent aging 725 °C, 2 hours (at a test temperature of 750 °C, s0,2 increases to 674 MPa, sВ to 697 MPa). This hardening is due to the release of dispersed particles of the Laves phase of Fe2Mo and carbide of type VC during aging. In the aged state, the steel retains its austenitic structure at high temperatures, and when cooled below 200 °C, it undergoes a γ → α transformation according to martensitic kinetics and acquires a hardness of 49 HRC. The achieved high-temperature (700...900 °C) strength characteristics of 4Х3Н3Г6М7Ф steel are twice as high as those of the high-temperature die steel 5Х3В3МФС (DI23) and are not inferior to the heat-resistant alloy ХН35ВТЮ (EI787). This makes it possible to effectively use it instead of commercially available heat-resistant martensitic die steels at operating temperatures above 700 °C. Keywords: die steels CATO, alloying, quenching, austenitic structure, dispersion hardening, high-temperature strength.

The short- and long-term properties of welded high-temperature-resistant thermoplastics

AbstractHigh-performance plastics, such as polyphenylene sulfide or polyphthalamide, are increasingly being used in highly stressed areas, primarily due to their outstanding thermal and mechanical properties. Due to the increasing demands on plastic components in terms of geometry, functional integration, etc., components produced by primary molding often have to be welded in an additional process step. Furthermore, there are often restrictions with regard to component cleanliness, which is why converting, non-contact welding processes are of great industrial interest. However, as a result of the changeover-step in these processes, the previously plasticized areas cool down. For materials with high melt temperatures this circumstance can lead to inadequate weld seam qualities.The aim of the investigations was therefore to expand the understanding of the process of welding high-temperature-resistant plastics, to identify optimum welding parameters and to determine the mechanical short- and long-term properties of the welds. Furthermore, a comparison was made between the changeover welding processes and single-stage vibration welding in order to clarify the relevance of short changeover times.It could be shown that a significant correlation exists between the changeover time, the melting temperature and the resulting weld strength. Furthermore, the selection of the welding process and thus the type of heat input seems to have an influence on the long-term properties of the welds at high test temperatures.

Effects of RF Magnetron Sputtering Power on the Mechanical Behavior of Zr-Cu-Based Metallic Glass Thin Films.

Zirconium-based metallic glass films are promising materials for nanoelectronic and biomedical applications, but their mechanical behavior under different conditions is not well understood. This study investigates the effects of radio frequency (RF) power and test temperature on the nanostructure, morphology, and creep behavior of Zr55Cu30Al10Ni5 metallic glass films prepared by RF magnetron sputtering. The films were characterized by X-ray diffraction and microscopy, and their mechanical properties were measured by a bulge test system. The results show that the films were amorphous and exhibited a transition from noncolumnar to columnar morphology as the RF power increased from 75 W to 125 W. The columnar morphology reduced the creep resistance, Young's modulus, residual stress, and hardness of the films. The creep behavior of the films was also influenced by the test temperature, with higher temperature leading to higher creep strain and lower creep stress. The findings of this study provide insights into the optimization of the sputtering parameters and the design of zirconium-based metallic glass films for various applications.

Creep behavior and viscoelastic-plastic models for polymer-blend HDPE geocell sheets based on the stepped isothermal method

Polymer-blend High Density Polyethylene (PHDPE) sheet materials have been developed in China as an alternative to the High Density Polyethylene (HDPE) materials for the manufacture of geocells. It is necessary to evaluate the creep properties of the geocell-reinforced structures to provide a reference for design of their service life and improve their application potential. In this paper, the Stepwise Isothermal Method (SIM) based accelerated creep testing, in which the test temperature was gradually increased but the load was kept constant, was employed obtain the long-term creep behavior of PHDPE and HDPE geocell sheets. Conventional creep tests were also carried out to assess the accuracy of the creep prediction. Furthermore, the Modified Burgers (MB) model and the Mon-linear Three-component (NLTC) model were proposed to predict long-term creep deformations of the PHDPE geocell sheets. The experimental results indicated that SIM creep tests could predict long-term creep deformations. The creep resistance of all three PHDPE, PHDPE-A, PHDPE-B, and PHDPE-C, was better than that of HDPE due to the addition of nylon 6 for the polymer-blending modification in HDPE. Comparison of the experimental data with the predicted data also confirmed that the MB and NLTC models could accurately model the viscoelastic-plastic creep behavior of PHDPE geocell sheets.