Deformation properties of arched glass fiber reinforced plastics structure under static load: Considering the soil cover and rise-span ratio

In this study, the load level, soil cover height, rise-span ratio, and arch foot constraint state were utilized to explore the mechanical properties of buried arch glass fiber reinforced plastics (GFRP) structures. Through the indoor scale-down test, the stress and deformation of arched GFRP structures under different load and soil cover height were investigated. Additionally, through the three-dimensional finite element method, the influence of the rise-span ratio and the constraint state of arch foot on the mechanical properties were obtained. The results indicate the new buried composite arch structure has excellent bearing capacity for the possible traffic load. Simultaneously, the semi-elliptical arch structure was believed to outperform the semi-circular arch structure when considering the external load. Specifically, increasing the soil cover height and reducing rise-span ratio were found to achieve the load-reduction effect.

Experimental study on axial compression buckling of glass fiber reinforced plastics solid pole with circular cross-section

Glass fiber reinforced plastics are widely used in civil engineering because of their advantages such as light weight, high strength, good pollution resistance, and corrosion resistance. This study investigated the buckling bearing capacity, failure characteristics, and slenderness ratios of GFRP solid bars with circular cross-sections subjected to axial compression. A total of 18 specimens were categorized into six groups. The slenderness ratios ranged from 57 to 123. It was found from experiments that the instability mode of the specimens was extreme point instability, and a bearing capacity platform phenomenon was observed when overall lateral instability occurred. The failure mode was axial and transverse tearing failure of the material in the middle of the specimen. During buckling, the tensile side was transformed from the compression of the resin matrix to tension in the fibers. The elastic modulus of glass fiber was much lower than that of the resin matrix. After tension occurred, increased deformation led to a rapid increase in lateral bending, which resulted in the phenomenon of the bearing platform. At ultimate deformation, brittle failure of the specimen occurred. The buckling load of the specimen decreased sharply with an increase in the slenderness ratio, and stress ratios decreased from 34.95% to 6.73%. It is suggested that the slenderness ratio not exceed 80. Finally, based on experimental results, a practical method for calculating the stable bearing capacity of solid GFRP poles is proposed.

Porous Ceramics Adsorbents Based on Glass Fiber-Reinforced Plastics for NOx and SOx Removal

To reuse waste glass fiber-reinforced plastics (GFRPs), porous ceramics (i.e., GFRP/clay ceramics) were produced by mixing crushed GFRP with clay followed by firing the resulting mixture under different conditions. The possibility of using ceramics fired under a reducing atmosphere as adsorbent materials to remove NOx and SOx from combustion gases of fossil fuels was investigated because of the high porosity, specific surface area, and contents of glass fibers and plastic carbides of the ceramics. NO2 and SO2 adsorption tests were conducted on several types of GFRP/clay ceramic samples, and the gas concentration reduction rates were compared to those of a clay ceramic and a volcanic pumice with high NO2 adsorption. In addition, to clarify the primary factor affecting gas adsorption, adsorption tests were conducted on the glass fibers in the GFRP and GFRP carbides. The reductively fired GFRP/clay ceramics exhibited high adsorption performance for both NO2 and SO2. The primary factor affecting the NO2 adsorption of the ceramics was the plastic carbide content in the clay structure, while that affecting the SO2 adsorption of the ceramics was the glass fiber content.

Comparison of Electrical Contacting Techniques to Carbon Fiber Reinforced Plastics for Self-Strain-Sensing Applications

The electrical conductivity of carbon fibers can be used to enable the design of intrinsically smart carbon fiber reinforced plastics (CFRPs). Resistance and impedance measurements of the structural material itself can then be used to measure physical stimuli such as strain or damage without requiring a dedicated sensor to be installed. Measuring the resistance with high precision requires good electrical contact between the measurement equipment and the conductive carbon fibers. In the literature, many different combinations of surface contacting material and surface preparation procedures are used, but only seldomly compared to one another. This article aims to compare frequently used electrical contact methods by analyzing their contact resistance to a pultruded CFRP rod. Furthermore, this study explores the change of contact resistance with increasing mechanical strain. The results show that contact resistance is highly dependent on both the material used for contacting the fibers as well as the surface preparation technique. From the combinations analyzed in this article, the electrodeposition in combination with a surface treatment using concentrated sulphuric acid shows the most promising results.