Experimental characterization of creep behavior of laminated bamboo composites based on stepped isothermal method

Self Cite

The benefits of using glued laminated bamboo (GLB) as a structural material are numerous, such as its low weight, high specific strength, and low carbon footprint. However, as a viscoelastic material, GLB materials exhibit creep, which is a significant characteristic that needs to be considered. To ensure the safety and serviceability of structures that utilize GLB, it is essential to accurately estimate the long‐term performance of GLB composites under external forces. This paper reports on an experimental investigation into the creep characteristics of GLB under tensile and compressive loads. The experiments were conducted at various load levels for a period of 500 h under a controlled environmental condition. The Burgers model and the five‐parameter model were used to characterize creep behavior and predict the long‐term deformation by extrapolating beyond the experimental period. The long‐term deformation of the GLB may be overestimated by the Burgers model due to its constant creep rate for the viscous component. In contrast, the five‐parameter model introduces a modification factor that results in a nonlinear viscous component, allowing a more accurate fit and a reasonable deformation estimate.Highlights Creep characteristics of GLB were studied under tensile and compressive loads. Burgers and five‐parameter models were used to describe the creep behavior. Extrapolation of Burgers model overestimates the creep deformation of GLB. Five‐parameter model provides reasonable deformation estimate for GLB.

Section: Resultsmentioning

confidence: 99%

“…The pressure during the hot‐pressing process is controlled at 10–20 MPa, depending on the thickness of the required GLB panel. A detailed description of the manufacturing process can be found in the literature 27 …”

Section: Experimental Programmentioning

confidence: 99%

Characterization and modeling of creep behavior of glued laminated bamboo

Liu,

Wang,

et al. 2023

Self Cite

“…CLT is an innovative engineered wood product that consists of a number of layers of dimension lumber that are stacked crosswise one by one and glued on their wide faces, and LVL is an engineered wood product that uses multiple layers of thin wood assembled with adhesives, as shown in Figure 1. Various scholars have conducted plenty of research on the mechanical and thermal properties, along with the performance of components at ambient and high temperatures, which lays a solid foundation for the application 9–12 . However, the good appearance of the material makes designers tend to expose the combustible surface, thus one important issue is to assess the fire risk based on the local conditions before practical application 13 …”

Section: Introductionmentioning

confidence: 99%

Experimental study on the combustion properties of four common engineered bamboo and wood composites

Cui,

Xu,

Tang

et al. 2023

Engineered bamboo and wood composites are increasingly utilized in construction due to their eco‐friendly, low‐carbon footprint, and superior mechanical properties. To investigate the effect of heat flux and grain direction on the combustion properties of parallel strand bamboo (PSB), laminated veneer bamboo (LVB), cross‐laminated timber (CLT), and laminated veneer lumber (LVL), a total of 54 specimens in 3 groups were tested through a cone calorimeter. Parameters including the ignition time, heat release rate, mass loss rate, and smoke production rate were investigated. The analytic hierarchy process method was adopted for a multi‐level, qualitative, and quantitative comprehensive fire risk assessment of the corresponding structural materials. The test results reveal that PSB and LVB demonstrated superior performance to the CLT and LVL through the comparison of four combustion characteristics parameters, despite their drawbacks and virtues. The heat flux increases in inverse proportion to the ignition time. As for the heat release rate, the larger peak value is accompanied by an earlier appearance, along with the greater average mass loss rate and the lower smoke rate of engineered bamboo. The peak heat release rate of engineered bamboo composites parallel to the grain is larger than that perpendicular to the grain, whereas other parameters are not significantly influenced by the grain direction. Compared with engineered wood, engineered bamboo composites have the potential to be a safer and more reliable building material in terms of fire risk assessment.Highlights Cone calorimeter was used to analyze the combustion properties of materials. PSB, LVB, CLT, and LVL were studied considering different grain directions. Analytic hierarchy process method was adopted for a fire risk assessment. Engineered bamboo has the potential to be a reliable building material.

Effect of environmental humidity on the creep behavior of flax fiber‐reinforced polymer composites

Hurk

Lugger

et al. 2023

Flax fiber‐reinforced polymer (FFRP) composites are emerging popular environmental‐friendly construction materials. However, their significant creep properties have been a major concern for using FFRP in load‐bearing structures. This article presents an investigation of the effect of environmental humidity on the creep behavior of the FFRP. Samples with flax fiber in 0°, 90°, and ± 45° were manufactured, respectively, by the vacuum infusion method. Accelerated creep tests were conducted on samples in different relative humidities (RH), and the results were analyzed by the time–temperature superposition principle (TTSP). It is found the creep development of samples with 0° and 90° fiber increases with the RH, and their 30‐year total strain in 97% RH is about 10 times higher than that in 11% RH. The samples with ±45° fiber are found not obviously sensitive to the humidity change. The scanning electron microscope (SEM) check indicates the change in the fiber–matrix interface and cracks between microfibrils in a fiber bundle is the main reason for the change of creep behavior in high humidity. This study may benefit the design of structures made of natural fiber‐reinforced polymer composites, especially for load‐bearing structures working in high‐humidity environments.