Sustained Load Research Articles

Time-dependent reliability of structures under consideration of fuzzy uncertainty

Time-dependent reliability (TDR) is the possibility that a structure or system under consideration can perform the intended function under specified service conditions over a given time instant under fuzzy uncertainty. This paper is mainly concerned to identify fuzzy variables, generate the membership function of the input variables and output quantities, analyze timedependent performance level, estimate the possibility safety index, and evaluate the TDR of the structures. To evaluate TDR by a possibilistic approach, the fuzzy uncertainty that is characterized by membership function is considered. The type of uncertainty defines the method of reliability analysis, i.e., aleatory uncertainty possesses a probabilistic approach, whereas epistemic uncertainty leads to a possibilistic approach. The TDR analysis of the structures subjected to sustained load and corrosion based on probability theory is well developed. On the contrary, the TDR of structures subjected to combined effects sustained load, corrosion, creep, and shrinkage based on possibility theory lack research. Thus, this paper is significant to evaluate the TDR of structures subjected to the aforementioned effects based on possibility theory. However, it requires a rigorous procedure, a single-loop optimization method (SLOM) is employed to evaluate the TDR of structures involving epistemic uncertainty. To enhance the validation of the proposed approach, several examples are thoroughly carried out.

Structural response of reinforced LECA aggregate concrete slabs subjected to high temperatures

This work reports tests conducted on nine one-way reinforced concrete slabs using lightweight expanded clay aggregate (LECA) as a slab weight reduction technique. Every slab had the same dimensions, steel reinforcement, and the same composition of concrete. The slabs were heated from their bottom faces through a fire chamber and subjected to a sustained line load. The specimens’ fire resistance performance and mechanical characteristics were evaluated after they had undergone the same testing conditions. The study parameters were the replacement of coarse aggregate with different percentages of LECA (20%, 40%), and different temperatures (400 ℃ and 700 ℃). Compared to the reinforced normal-weight concrete slab, the reinforced LECA aggregate concrete slabs’ fire resistance and flexural strength decreased by LECA. The slabs’ deflection rose as the LECA increased. The largest increase in slab deflection was 37.2%, while the most notable decrease in ultimate load capacity was roughly 35.1%. The stiffness depreciation was substantial, though, at roughly 50%. The results for LECA-reinforced aggregate slabs not exposed to high temperatures support this conclusion. Reinforced LECA aggregate slabs maintained structural integrity after fire testing.

Time-dependent response of continuous steel-concrete composite beams under sustained loading

Although the long-term behavior of composite beams raises critical concerns in their application, only a few investigations have been conducted on the time-dependent response of continuous composite beams (CCBs). Herein, long-term tests were conducted on four two-span CCBs with different loading ages. The shear stiffness and time-slip relationship of flexible shear connectors were evaluated by carrying out short-term and long-term push-out tests. The experimental results revealed that loading age substantially affected the development of deflection, interface slip, crack, and internal force redistribution of CCBs under sustained loads. A finite element model (FEM-2) of test specimens was developed, considering the damage evolution, creep and shrinkage of concrete slab, and stiffness degradation of connectors. After the FEM results were verified against the experimental data, the developed FEM-2 model was implemented to further investigate the influences of loading age and loading level on the long-term performance of CCBs.

CREEP AND ELECTRICAL PROPERTIES OF CARBON NANOTUBE YARNS FOR LONG-TERM APPLICATIONS

One of the primary challenges to turning CNTs into commercial applications is the feasibility to manufacture macroscopic structures that mirror the extraordinary properties of individual CNTs. CNT yarns (CNTY) are an alternative to overcome this challenge. However, most yarn-like structures are exposed to dynamic systems, like creep and/or fatigue, and limited studies are published predicting their behavior. Therefore, the current study aimed to assess the behavior of CNTYs under creep situations and establish a relationship with their electrical properties. Five layers of CNTs were drawn from the MWCNT forest, placed one on top of the other, and scrolled into a 250 mm yarn, that was later twisted to 2000 twists m−1. Afterward, these CNTYs were densified with acetone. Creep experiments were performed with a sustained load of 50, 70, and 80 % of the YBL. The yarn behavior seen during creep experiments was unexpected, which, although partial breakage of the yarn was seen, it sustained the creep load much for longer periods. The mechanism proposed for the phenomenon includes CNT alignment and void elimination at first, followed by partial CNT sliding, with breakage of van der Waals forces. As the creep load continues, CNTs are able to rebind to their neighbors and recover their strength before total failure. Mechanical gripping due to friction is also occurring between nanotubes which favors a strength increase. This behavior indicates that there is a regeneration of van der Waals forces occurring among the CNTs, which recovers the strength of the yarn under constant load, increasing creep lifespan. The time to failure obtained under creep load is about 9, 10, and 11 days to failure for CNTYs at 50, 70, and 80 % of YBL, respectively. Raman results showed that ID/IG ratio remained the same after mechanical loads, which indicates that no structural modification is seen in the CNTs when static and/or dynamic mechanical systems are imposed on the yarn. The electrical conductivity of a CNTY is improved after the mechanical tests, increasing by 5.9 and 6.7% after static tensile and creep, respectively. The improvement of electrical conductivity is attributed to densification, which leads to an enhancement of the intertubes contact area among the nanotubes within the yarn.

Time-dependent subcritical crack growth and its mechanism in Ni-based single crystal superalloys at 500 °C

The subcritical crack growth behavior under sustained loading and its microscopic mechanism in <100> oriented single crystal (SC) Ni-based superalloys subjected to a relatively low temperature condition (500 °C) are critically investigated. An evident time-dependent crack growth (TDCG) phenomenon is observed even at such a temperature condition, but its rate (da/dt) is significantly small and weakly dependent on the crack length, i.e. the stress intensity (K) value. The cross-sectional observation of a crack tip region by electron microscopy (SEM/TEM), together with the conventional fractography, reveals the following points: the macroscopic crack path shows pronounced branching influenced by the {100} planes; most dislocations in the γ’ phase near the crack tip are rectilinearly aligned and locked on the {100} planes; the crack tip dislocations provide the microscopically preferable oxidation paths. These points strongly suggest that the dislocation-mediated micro-oxidation process plays a major role in the observed anisotropic TDCG mechanism that eventually leads to the anomalous da/dt - K property.

Determination of SIFs and application of a SIF-based fracture criterion for concrete-rock interface under sustained loading

This study proposes an effective method to determine the stress intensity factors (SIFs) of the interface crack considering the viscoelasticities of the bilateral materials and verifies the feasibility of the initial fracture toughness-based fracture criterion for the concrete-rock interface under sustained loading. Firstly, low-level sustained loading tests were conducted on the composite concrete-rock specimens with respect to two interface roughness degrees and two sustained load levels less than the initial cracking load. Then, an implicit creep equation was employed to characterise the viscoelasticities of bilateral materials and then calculate the mechanical responses of the concrete-rock interface in the low-level sustained loading test. The SIFs of the interface crack under sustained loading were determined by using the elastic strain energy density ahead of the crack tip. By averaging the SIFs over the radius of the core region of the crack tip, the representative SIFs under sustained loading were obtained. The test results indicated that the SIFs showed decreasing tendencies under sustained loading, and the initial fracture toughness can be considered as a material property of the concrete-rock interface. The initial fracture toughness-based fracture criterion was verified to be feasible to determine the initial cracking status of the concrete-rock interface under sustained loading. In addition, due to the reductions of the SIFs under sustained loading, additional loads were required to compensate the losses of the SIFs, leading to the enhancement of the initial cracking loads after experiencing the sustained loading.

Shape-locking in architected materials through 3D printed magnetically activated joints

Shape morphing is the ability of objects to adapt to different shapes and reduce stress concentrations through increased contact area. This is a common trait of natural and engineered objects and has several applications in, among others, soft robotics and orthopedic implants. Shape morphing is achieved through flexible materials or rigid components with either kinematic or compliant joints. An additional step, namely shape locking, is needed for sustained load support. Activation of a locking mechanism can be done with any energy, among which magnetism is one. Here, we present the implementation of a magnetic locking mechanism for kinematically deformable metamaterial structures that maintain shape and support loads upon locking. The structure consists of 3D printed rigid magnetic and non-magnetic components connected by hinges. We created several prototypes of the proposed designs using two additive manufacturing methods (i.e., material extrusion and multi-material jetting) and demonstrated its application in a closed-loop grid for arbitrary shapes. Moreover, we characterized the performance of the prototypes using mechanical tests and multibody kinematic system simulations. This work highlights the viability of the locking concept and provides design considerations for future applications. Further improvement and optimizations are needed for increased efficiency and effectiveness.

Features of NK cell phenotype virus genotype-driven chronic viral hepatitis C

Elimination of the hepatitis C virus (HCV) due to direct antiviral drug (DAD) action affects alteration in virus phenotype and, accordingly, NK cell functional activity. However, the published data are very contradictory. The aim of the study was to investigae alterations in NK cell subset phenotype after DAD treatment of HCV genotype-dependent chronic viral hepatitis C (CVHC) patients. Materials and methods. 111 CVHC patients and 21 healthy volunteers were examined. The diagnosis was established on epidemiological, clinical and laboratory data. All 111 subjects with CVHC received direct antiviral drugs Sofosbuvir and Velpatasvir for 12 weeks. The study of the NK cell phenotypes wwas analyzed by multicolor flow cytometry. Results. A decreased count of cytokine-producing along with increased frequency of cytotoxic NK cells were found in CVHC patients blood samples with various HCV genotypes prior to DAD treatment. The imbalance of cytotoxic cells with a high level of functional activity was also found in CVHC patients regardless of HCV genotype. The patients with HCV genotypes 1 and 3 showed significantly increased level of immunoregulatory NK cells. In addition, increased count of glycohydrolase (CD38) and ecto-5'-nucleotidase (CD73)-expressing NK cells were found in patients with HCV genotypes 1 and 3. Hence, such alterations in NK cell phenotype in CVHC patients were presented as sustained high viral load which peaking at carriers of HCV genotype 1 that was minimal in patients with HCV genotype 2. The most prominent change in NK cells after DAD treatment was found in CVHC patients with HCV genotype 2 (normalization of CD8-expressing NK cell subset composition and count). Only patients with HCV genotype 2 after treatment had increased frequencies of peripheral blood double-negative CD38–CD73– NK cells. Patients with HCV genotypes 1 and 3 also showed minimally improved in NK cell subset composition after DAD treatment. Conclusion. Evaluation of specific changes in NK cell phenotype during DAD treatment of CVHC patients driven by HCV genotype undoubtedly is of importance and high relevance. The results obtained are novel and complement the insights into CVHC immunopathogenesis. Analysis of NK cell phenotypes and functional activity in patients with CVHC may promote development of new methods for treating HCV infection.

Effects of extreme cyclic loading on the cushioning performance of human heel pads under engineering test condition.

Human heel pads commonly undergo cyclic loading during daily activities. Low cyclic loadings such as daily human walking tend to have less effect on the mechanical properties of heel pads. However, the impact of cyclic loading on cushion performance, a vital biomechanical property of heel pads, under engineering test condition remains unexplored. Herein, dynamic mechanical measurements and finite element (FE) simulations were employed to explore this phenomenon. It was found that the wavy collagen fibers in the heel pad will be straightened under cycle compression loading, which resulted in increased stiffness of the heel pad. The stiffness of the heel pads demonstrated an inclination to escalate over a span of 50,000 loading cycles, consequently resulting in a corresponding increase in peak impact force over the same loading cycles. Sustained cyclic loading has the potential to result in the fracturing of the straightened collagen fibers, this collagen breakage may diminish the stiffness of the heel pad, leading to a reduction in peak impact force. This work enhances understanding of the biomechanical functions of human heel pad and may provide potential inspirations for the innovative development of healthcare devices for foot complex.

Performance of recycled aggregate concrete (RAC)-filled steel tubular (FST) members and K-joints under lateral impact

A series of tests are conducted on 26 recycle aggregate concrete (RAC)-filled steel tubular (FST) members and 25 RAC-FST K-joints on a drop hammer rig. Salient parameters considered in the experimental program include the axial load ratio, the replacement ratio of recycled coarse aggregate (RCA), the height of the hammer and the application of combined corrosion and sustained loading, et al. The shrinkage and creep deformation of core RAC is measured for 185 days, and the influence of key parameters on the structural performance of both RAC-FST members and K-joints are analyzed. A finite element (FE) model is established and verified against the test results. Considering the effects of combined chloride corrosion and sustained loading, the FE model is successively employed to investigate the behaviour of RAC-FST members and K-joints under lateral impact, including the failure mode, the time history relationships of impact load and deflection, the distribution of internal force and stress, et al. The axial compression performance of the member and the chords of K-joints after being subjected to combined loading is evaluated. On the basis of the parametric analysis, simplified models considering the effects of chloride corrosion and sustained loading are obtained to calculate the dynamic flexural capacity of the RAC-FST members and the chords of RAC-FST K-joints under impact loads.

Experimental Study on the Flexural Performance of Composite Beams with Corrugated Steel Webs under the Coupled Effect of Chloride Ion Erosion and Sustained Load

The steel corrosion of composite beams with corrugated steel webs (CBCSWs) is prone to occur in a chloride environment, and the load can change the rate of steel corrosion, thereby affecting the degradation of the mechanical properties of CBCSWs. In this paper, the flexural behavior of CBCSWs under the coupled effect of chloride ion erosion and sustained load was studied through an accelerated corrosion test and bending failure test. The results showed that, during the accelerated corrosion test, the deflection at the mid-span of the corroded CBCSWs increased more and faster than that of the uncorroded CBCSWs, and the stress of the externally prestressed tendons of the CBCSWs did not change significantly. During the loading failure process, the relative slip between the web and the concrete plates of the corroded CBCSWs had not been fully developed. The ultimate load and ultimate deflection of the corroded CBCSWs were decreased by 41.1% and 17.9%, respectively, compared to those of the CBCSWs before corrosion. The quasi-plane section assumption was still approximately applicable to the corroded CBCSWs. Compared with the uncorroded CBCSWs, the shear lag effect of the top plate of the corroded CBCSWs was more obvious. The externally prestressed tendons of the corroded CBCSWs could not give full play to their performance during the process of loading failure.

Physical modelling of subsea structure removal via thermally induced pore pressure

Given the requirements of environmental agencies, the decommissioning of subsea structures, including removal, recycling, restructuring or re-adaptation, is inherent to deepwater oil exploration activities. During removal by lifting, the possible development of negative excess pore pressure (i.e., suction) in the soil beneath the structure significantly hampers the recovery of subsea infrastructure. This study presents a method for potentially reducing this suction by heating the fine soil under the foundation during uplift to produce excess thermally-induced positive pore pressure, which may reduce or eliminate suction. Reduced-scale physical modelling studies of mudmat/skirted like foundation structures showed that the negative pore pressure generated during pullout was in certain amount counterbalanced by the thermally-induced positive pore pressure, facilitating their removal. However, this process depends on the magnitude of the sustained loading with respect to the pullout resistance. Upward displacements take place just after heating, without further load increments and the displacement rate is dependent on the level of sustained load.

A coupled thermal-analytical and mechanical approach to investigate the behavior of bonded anchors cured at sub-zero temperatures

In post-installed connection in reinforced concrete structures, bonded anchors are commonly adopted when elevated mechanical performances are required. Such performances may be significantly impaired by adverse service conditions, above all temperature variations with respect to room ambient one. It is also generally acknowledged that the curing temperature may impact on the anchor performances, to the extent that all the main existing qualification procedures assess the anchor behavior when cured at different temperatures, in particular below zero Celsius degree. However, among the few investigations focusing on the impact of a low curing temperature on the long term behavior of an anchor, a low effort exists in addressing the relationship between the anchor mechanical behavior and the thermal properties of the bonding agent. The paper proposes a coupled thermal-analytical and mechanical approach to detect potential critical issues in the long term mechanical behavior of the anchor as a function of the adhesive behavior, as investigated by thermal or thermo-mechanical analyses. To the scope, a wide investigation on two adhesives is carried out comprising MDSC, DMA, pull-out and sustained load tests. On the basis of the obtained results, it is concluded that some thresholds in the variations of degree of conversion and phase transition temperatures may indicate a negligible impact of a low curing temperature on the anchor mechanical behavior, but also that existing qualification procedures are not able to capture the anchor behavior, when cured at low temperatures and subjected, during its service life, to temperatures higher than room ambient one.

Coupled effects of simultaneous autogenous self-healing and sustained flexural loading in cementitious materials

The self-healing efficiency of cementitious materials might be impaired by external loading. This study investigates the coupled effects of sustained flexural loading and self-healing mechanisms. To this end, prismatic mortar specimens were pre-cracked at two days with 10-μm wide cracks under bending. Some beams were then immersed for healing and simultaneously loaded for about 4 weeks using an innovative three-point bending test device allowing bending creep displacement measurement. At the same time, reference beams were immersed without load. After the healing period, the specimens were reloaded to assess the effect of creep and healing on the stiffness and strength recovery. It was found that, during immersion, the creep deformation gradually decreased with time, probably due to the precipitation of healing products. However, after immersion, the mechanical properties recovery of specimens undergoing creep during self-healing decreased by 12 % compared to the reference specimens. Microscopic observations were consistent with the mechanical recovery measurements, suggesting partial healing of the loaded specimens.

Sensitivity of crack-growth lives to sustained thermal gradients

This paper investigates the effect of path-dependent material properties on predicted crack-growth lives with material properties set at the instantaneous crack-tip location. Specifically, we focus on cracks advancing through thermal gradients with temperature-dependent crack-growth properties. Here, material properties that describe fatigue crack growth under cyclic load and time-dependent crack growth under sustained load have been set to capture the response of the high-temperature alloy ME3. This study investigates the effect of peak temperature, peak stress, temperature gradient, hold time, and time to reach full loading. To perform this investigation, we design a simple example problem that captures key features of fatigue crack growth without introducing unnecessary complexity. Results indicate that increasing lives are associated with lower crack-tip temperatures due to cooling thermal gradients that reduce crack growth per cycle. Furthermore, these results reveal minimal impacts on lives for temperatures with negligible time-dependent crack growth, and larger increases in lives are expected for cracks with more appreciable time-dependent crack growth. Designers may employ these ideas to extend useful lives of applications with strong spatial gradients in the material response, e.g., recent efforts to design internal cooling passages into gas-turbine engines using additive manufacturing.

Durability assessment of GFRP bars exposed to combined accelerated aging in alkaline solution and a constant load

Employing fiber-reinforced polymer (FRP) bars as reinforcement in reinforced concrete (RC) elements is a promising approach to solve the issues associated with steel corrosion in RC elements owing to the high corrosion resistance of FRP bars. Although a number of studies on the durability of glass FRP (GFRP) bars in the alkaline environment are available, most of which ignored the influence of sustained loads. This paper presents an experimental program on tensile tests on GFRP bars made of three distinct matrix resins (i.e. epoxy, vinyl ester and polyester), after exposure to combined alkaline solution immersion, an elevated temperature and a constant load. A novel level device was developed, and a prescriptive constant axial stress was imposed on GFRP bars, and the bars with or without a sustained load were exposed to an alkaline solution and an elevated temperature of 60 °C. The main parameters investigated in the present study included aging times, constant stress levels, exposure conditions and types of resin matrices of the GFRP bars. The residual tensile properties of the GFRP bars were tested and presented. The microscopy method was adopted to check the internal defects in the GFRP bars with or without exposures. Test results show that three months of exposure in alkali and loading could lead to more than 40% strength decreases of the GFRP bars. Compared with GFRP bars after exposure to alkaline solution solely, the presence of the constant tensile load only leads to small further detrimental effect in tensile properties of GFRP bars.

Nanoclay-Modified Hyaluronic Acid Microspheres for Bone Induction by Sustained rhBMP-2 Delivery.

Microspheres (MSs) are ideal candidates as biological scaffolds loading with growth factors or cells for bone tissue engineering to repair irregular alveolar bone defects by minimally invasive injection. However, the high initial burst release of growth factor and low cell attachment limit the application of microspheres. The modification of microspheres often needs expensive experiments facility or complex chemical reactions, which is difficult to achieve and may bring other problems. In this study, a sol-grade nanoclay, laponite XLS is used to modify the surface of MSs to enhance its affinity to either positively or negatively charged proteins and cells without changing the interior structure of the MSs. Recombinant human bone morphogenetic protein-2 (rhBMP-2) is used as a representation of growth factor to check the osteoinduction ability of laponite XLS-modified MSs. By modification, the protein sustained release, cell loading, and osteoinduction ability of MSs are improved. Modified by 1% laponite XLS, the MSs can not only promote osteogenic differentiation of MC3T3-E1 cells by themselves, but also enhance the effect of the rhBMP-2 below the effective dose. Collectively, the study provides an easy and viable method to modify the biological behavior of microspheres for bone tissue regeneration.

Flexural behavior of long-term loaded RC beams strengthened by ultra-high performance concrete

This study aims to investigate the flexural behavior of reinforced concrete (RC) beams strengthened with ultra-high-performance concrete (UHPC) after being loaded with long-term sustained loads for more than 20 years. Seven RC beams, originally fabricated in 1998, are categorized as the one-time pouring unnotched beam (Overall beam), one-time pouring notched beam (Notched beam), and two-time pouring beam (Repaired beam). These RC beams were firstly tested under the effect of long-term sustained loads which lasted 23.6 years. Subsequently, notched beams were strengthened using UHPC (hereafter named as Strengthened beam), which are tested under four-point bending test to investigate the significance of strengthening using the UHPC. Long-term load effects on the flexural performance of RC beams, including creep, cracking, concrete carbonization, and steel rebar corrosion were tested and analyzed. Test results showed that the maximum carbonization depth was less than the concrete cover depth and the steel rebars corrosion was among 1.51–2.47%, which indicates that the steel rebars inside the beam are well protected and are almost free of rust. The bearing capacity of the strengthened beams were increased by 24.6–48.6% compared with that of the Notched beam, which emphasizes the significance of strengthening using the UHPC. The displacement ductility of the strengthened beams was decreased by 82–94% compared with that of the Overall beam, however no brittle failure was observed during the test. It is worth mentioning that the internal changes, caused by the long-term sustained loading, could not be completely changed by adopting UHPC strengthening, while the stiffness reduction caused by long-term loading considerably influenced the flexural behavior of the UHPC strengthened beams. In addition, more attention shall be paid to the UHPC-NC vertical interface which remarkably affected the flexural performance of the Strengthened beams.

Effects of sustained load and reinforcement spacing on the evolution and spatial characteristics of corrosion damages in RC segmental specimens

Because of the combined actions of sustained load and corrosive agents, premature steel corrosion and rapid material deterioration can be extensively observed in the reinforced concrete (RC) shield tunnels in an aggressive environment. Such a degradation accompanies with diverse corrosion damages in segmental lining, such as nonuniform steel corrosion and crisscrossed cracks on concrete surface, which shall be exacerbated due to congested steel arrangements and complex stress states in segment. In this paper, a corrosion-accelerated experiment on RC specimens in a tunnel segment was conducted by employing galvanostatic method and a designed loading system. Multiple rebars with different spacing distances were considered in two types of RC specimen. Deterioration damage evolution of RC specimens, including deterioration deformation and surface cracking patterns, has been investigated with an emphasis on the influence of sustained load and interaction of corroded rebars. Both visual inspection and distributed optical fiber sensing technology were applied to track the surface concrete cracking of bearing specimens. Meanwhile, the spatial variability of steel corrosion in bearing specimens was elaborated. The impacts of applied tensile load and reinforcement spacing on the spatial correlation of steel corrosion in longitudinal and transverse directions of rebars were experimentally illustrated. The experimental findings can help in improving the probabilistic model associated with nonuniform steel corrosion of several spaced rebars in tension and identifying the extent of corrosion damages in the load-bearing RC segments.

Influence of network structure determined by Time-domain [formula omitted] Double Quantum NMR on the creep properties of non-stoichiometric epoxy-amine resins aimed for chemical anchoring applications

Chemical anchors, used to fasten structural components, are prone to creep under sustained loading, which significantly affects their long-term performance and service life. In this study, the molar ratio, that determines the ultimate network structure of an epoxy-amine resin system, is systematically modified to investigate the creep properties. The percentage of physical entanglement and defects (free and dangling chains) for each formulation is obtained by Time-Domain 1H Double Quantum (DQ) Nuclear Magnetic Resonance (NMR) measurements. The crosslink density values from the dynamic mechanical analysis (DMA) and the network parameter from the NMR measurements show a strong linear correlation. Tensile tests were performed to determine the influence on the mechanical properties and set the load levels for tensile creep measurements of the selected formulations. Epoxy-rich systems (Epoxy-Amine adduct) show the highest modulus and tensile strength but inferior creep properties compared to stoichiometric and amine-rich (Amine-Epoxy adduct) compositions. This can be attributed to the build-up of several network structures with higher content of free and dangling chains leading to lower deformation resistance. At high loads, the entanglement density has an increasing impact on the creep behavior compared to defect-rich systems. Modeling using the Findley approach was carried out to link the obtained creep parameter with the material properties. Therefore, this work aims to deepen the understanding of the molecular-scale structures of epoxy resins required for material and design optimization, by investigating the correlation between network structure and creep properties.