Creep analysis of E‐glass/vinyl‐ester laminated composites for underground vault structures

Abstract

Creep is eminent in fiber reinforced polymer matrix composite materials given the susceptibility of polymers to constant loading. The response of polymer matrix composites used in retrofitting vital infrastructure to long‐term flexural loadings is investigated to elucidate the effect of creep. The experimental approach consisted of first establishing a benchmark of the quasi‐statically tested flexural properties. A fresh set of samples were then flexural tested for an extended period. Failure was determined to be strain‐driven in both quasi‐static and long‐term testing conditions. The mechanical properties were found to be insensitive to the strain rate (in the low strain regime), while being mildly sensitive to creep loading. The flexural response also showed dependence on the historic creep loading. The creep strain was successfully fitted into Baily‐Norton power law, which allowed for forecasting the creep life based on the critical strain failure criteria. The overall results explicate the interrelation between long‐term loading and fidelity of composites‐based infrastructures.

Multiscale Characterization of E-Glass/Epoxy Composite Exposed to Extreme Environmental Conditions

“…The mechanical properties of the E-Glass/Epoxy used in the production of modular composite panels for underground vault application were found to be generally insensitive to loading rate but resulted in permanent damage at a relatively low strain level. Alternatively, E-Glass/Vinyl-ester PMCs were reported to be mildly sensitive to the creep strain [5]. A major shortcoming of these previous investigations is the lack of analytical chemistry and morphological characterizations to substantiate and corroborate the reported results, especially in fire events.…”

“…Analogous to the major class of composite materials, PMCs offer superior strength-to-weight, stiffness-to-weight, and toughnessto-weight ratios, compared to their single-phase constituents. The construction industry, among others, found refuge in composite materials to combat several challenges, such as (1) installation time and cost since composite technologies could produce near-netshape parts [1] and (2) the deterioration of infrastructures due to its potential field life longevity [2][3][4][5]. Infrastructures and structures are continually enduring harsh and demanding loading, operating, and environmental conditions that are somewhat distinctive from other industries [6].…”

“…In addition, reinforcement using natural materials continues to take center stage in scientific and engineering communities. However, most composite-based deployed infrastructures are made using glass fibers, which exhibit remarkable strength in simple tension but suffer under shear and bending loading scenarios [5,7,8]. Therefore, the polymer matrix plays a significant role in load-bearing and non-bearing applications, protecting the brittle glass fibers in non-axial loading scenarios against shearing stresses that may result in catastrophic failure.…”

“…The effectiveness of the fire-retardant properties of the composite panels was demonstrated by mitigating the impact of fire in the absence of dust and oil surface contamination. Additionally, the flexural creep response of the same composite skins was characterized and elucidated as a function of high static stress, orders of magnitude higher than those experienced by the panels in deployment, and different strain rates [5]. The mechanical properties of the E-Glass/Epoxy used in the production of modular composite panels for underground vault application were found to be generally insensitive to loading rate but resulted in permanent damage at a relatively low strain level.…”

Research and prediction of creep behavior of triaxial warp‐knitted composites by time–temperature equivalent principle

“…Creep is the most direct expression of the viscoelastic properties of polymers [4][5][6] and is also one of the main failure forms of material. Many engineering problems include creep 7,8 mainly exists in fan blades, bridges, parts and other places and has a great impact on safety performance of structure part. The multiaxial warp-knitted fabric has excellent mechanical properties in all directions as a composite material reinforcement and is widely used in fan blades, aerospace, construction, and other fields [9][10][11] and gradually replaces traditional materials.…”