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Nowadays, study on the bistable composites due to the using of them in morphing structure has become more and more important. Unidirectional composites have different thermal expansion coefficients in longitudinal and transverse directions. This difference in thermal expansion coefficient is caused the composites to bend like bimetals due to the raise in temperature and bistable composites are derived. In this research, in order to study effects of fabrication method the square-shaped bistable composites laminates with asymmetric layers were prepared and investigated. Different kinds of bistable composite laminates were fabricated by thermoplastic PVC and glass fibers and the effects of composites laminate's dimensions and mold's temperature were investigated. The maximum height of the bistable composite laminate is selected as the output of experiments. The results derived from ANOVA analysis showed that the dimensions of the laminates has the highest effects on bistability height and the effects of mold temperature are very low. It was also determined that with the larger dimensions of composite laminates and lower mold's temperature, the heights of bistability were higher. Also, these bistable composite laminate were simulated in ABAQUS and the simulation results were compared with the experimental results. The results indicated that simulation method anticipated the higher bistability height rather than the experimental results and the difference between these results are less than 10% in all specimens.

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For safe underground excavation, different supporting system can be used in weak ground conditions. However, rock mass instability does not give opportunity to install an appropriate supporting system. Pre-reinforcement of tunnel face can be an effective solution for this condition. Fiber glass dowels are one of the most efficient and economic methods of ground reinforcement. Fast installation, flexibility in using with other supporting systems … are the other advantages of this pre-reinforcement.
This paper studied numerically the behavior of the longitudinal fiber glass dowels which may accompanied with the different supporting system i.e. with shotcrete layer as the main supporting system or with pre-cutting system as another pre-support method. The analyses was carried out by FLAC ^3D in different weak ground condition subjected to different in-situ stresses implying tunnel depths. The fiberglass forces as well as tunnel center displacements are the output of this simulation.
The results showed the location of critical zones developed in tunnel face in non-hydrostatic stress field. It leads to employ more concentration of dowels on those zones. As well, the best result for the dowels could be seen when they were accompanied with pre-cutting system.
Finally, from the results of numerous analyses, mathematical formulations were presented to fast calculate the maximum stress of dowels and strain of the tunnel center in any different condition of weak ground condition.