This study aimed to analyze the mechanical properties and damage characteristics in uniaxial tensile loading of two hybrid composite laminates consisting of an ortho-therephthalic polyester matrix reinforced by bidirectional jute fabrics and E-glass fibers, with different configurations and types of geometric discontinuities in the longitudinal section, characterized by the presence of a circular hole and semicircular notches. A semi-empirical study was conducted using the residual properties obtained in mechanical tests, as well as the Point Stress Criterion (PSC) and Average Stress Criterion (ASC) failure theories. This study is based on the calculation of distances (d0 and a0) in the neighborhood of both the hole and the notches, the area of failure stress. The results show the direct influence of geometric discontinuity and residual and modulus strengths in all the parameters studied. With respect to failure theories, only the PSC showed good agreement when the K equal to 2.36 or 2.58 values was used.

The damage mechanism of reinforced plastics may be present in many different ways, since it depends on many factors. Highlights may be given to the effect of stress concentration in of geometric discontinuity in the sections of these structural elements, which in general always leads to certain characteristics of the fracture. In the case of glass fiber reinforced plastics (GFRP) it is expected the same tendency, beyond the influence of reinforcement and its internal orientation in the layers (anisotropy). The aims of this work are detailed study of the influence of the holes (longituninal section) in the characteristic fracture in GFRP submitted to tensile loading. Three different configurations of composite laminates were studied: two reinforced with Eglassfiber bidirectional textil fabric and the other only with short mats, also Eglassfiber. The results showed the influence of all parameters listed above in the final fracture characteristics and residual properties.

Natural fiber reinforced plastics (NFRP) have awakened considerable interest in the area of polymer composites, because of the need to develop new, environmentally friendly materials. One of the most complex ways of manufacturing this type of material is in the form of ultrathin laminar layers; however, this process hinders mechanical testing, mainly three and four-point bending. The present investigation faces this challenge and shows the influence of parameters, such as the grammage of reinforcing fabric and lamination process, on strength, stiffness and fracture characteristics for three-point bending in this type of structural element. The industrially manufactured laminas were composed of orthophthalic polyester resin reinforced with licuri fibers. Macromechanical and micromechanical analyses were conducted in the study of fracture characteristics for all the parameters. The mechanical behavior in the three-point bending of the laminar composite showed that the use of licuri fiber to obtain natural fiber-based plastic is completely viable.