The effect of laminate stacking sequence and fiber orientation on the dynamic response of FRP composite slabs

In this paper, different stacking sequences (0 / ± 45/90°) of laminated FRP slab under human-induced loads using finite element techniques are investigated to assess the dynamic characteristics of a composite floor and corresponding human comfort problems. Four layers of FRP, with different angles comprising 256 cases, are modeled using ANSYS software. Load models with variable parameters are applied as pattern loads. Material properties and damping ratio are calculated separately for each case with the aid of MATLAB software and considered as input to ANSYS for obtaining the maximum responses in terms of deflection and acceleration from the walking load of people. Then the results are compared with the limiting values proposed by the design standards. A comparison of the two results reveals that 54 cases of investigated FRP laminate seem to be ideal for practical use in satisfying both the acceleration and displacement requirements. This study was carried out to provide a more realistic evaluation of this type of structure when subjected to vibration due to human walking

Mechanical Response of High Strength Fibre Reinforced Concrete Under Extreme Loads

High Strength Fibre Reinforced Concrete (HSFRC) presents great advantages when compared with conventional concrete under static loads and thus, it constitutes a promising material to withstand extreme loads. An experimental and numerical research carried out with the objective of developing design criteria for HSFRC use in protective structures construction is presented. The mechanical behaviour of HSFRC elements under extreme loads is experimentally and numerically analysed. Numerical models represent useful tools for the design of this type of HSFRC applications but they should be carefully calibrated and validated with experimental results. HSFRC prisms and slabs including different types of hooked-end steel fibres are tested under static, blast and impact loads. Material models at the meso and the macro scale are developed, they are calibrated with characterization tests and validated with experimental results. Experimental results are analysed with the aid of numerical models showing the effect of fibre type and content under extreme load. Numerical models are able to reproduce the blast and impact tests results and give additionally information about the local and structural response under impulsive loads that could be valuable for the design of protective structures