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Fir wood flour may be used as filler in glass reinforced composites due to the lower content of tannins in comparison with oak wood flour (Cerbu et al. 2010). This work focuses on the behavior of E-glass / fir wood flour / epoxy hybrid composites in mechanical tests (three-point bending tests, and Charpy impact tests) after immersion in water for 1177, 3048, and 6572 hours. Alternating layers were reinforced either with glass fabric or with fir wood flour. After 3048 hours of immersion, the flexural properties decreased: the modulus of elasticity (MOE) in bending and maximum flexural stress σ decreased by 13.16% and 37.54% respectively, with respect to the values recorded in the case of the dried specimens. The properties recovered a little after saturation because they increased after 6572 hours of immersion: MOE was greater (4.36%), while maximum flexural stress was greater (6.78%) with respect to the values corresponding to the specimens tested after 3048 hours of immersion. In the Charpy test, the impact strength K was measured. The damage (cracks developed at matrix-glass interface) caused by water absorption is discussed in order to explain the degradation of the mechanical properties. The adding of the wood flour led to the increasing of the modulus of rigidity EI in bending and it is proved by comparing with the results obtained in case of glass / epoxy composite without wood flour. Components for outdoor furniture (gardens) could be an application of the hybrid composite analyzed in this paper. Brasov, 29 Eroilor Avenue, 500036, Brasov, Romania; b: Department of Wood Processing and Wood Products Design, Faculty of Wood Engineering, Transilvania University of Brasov, 29 Eroilor Avenue, 500036, Brasov, Romania; *Corresponding author: cerbu@unitbv.ro Keywords INTRODUCTIONHybrid composite materials represent a class of composites that may be reinforced with different kinds of materials in the same layer by using hybrid woven fabrics (e.g. carbon / Kevlar fabric). Other hybrid composites are made of different kinds of layers that are reinforced with only one kind of fibers and layers alternate.The E-glass / fir wood flour / epoxy composites analyzed in this paper were from the last class described above because the layers reinforced with glass fibers alternated with the layers reinforced with fir wood flour. Such a hybrid composite should combine the advantages of wood fibers described below within this section (Klyosov 2007) with the advantages of the glass fibers (Cerbu et al. 2009;Zhou et al. 2013;Wang et al. 2014).Wood plastic composites (WPC) are widely used (Klyosov 2007) because the addition of the wood flour to plastics may potentially lead to material cost reductions while mechanical characteristics can be improved. PEER-REVIEWED ARTICLEbioresources.com Cerbu et al. (2016). "Wood/ glass epoxy composite," BioResources 11(4), 8364-8385. 8365Wood species vary across the world according to geographic area. For example, in the temperate zone, common tree species include fir, oak, beech, hornbeam...

The aspects regarding the stiffness of the connections between the beams that support the storage pallets and the uprights is very important in the analysis of the displacements and stresses in the storage racking systems. The main purpose of this paper is to study the effects of both upright thickness and tab connector type on the rotational stiffness and on the capable bending moment of the connection. For this purpose, a number of 18 different groups of beam-connector-upright assemblies are prepared by combining three types of beams (different sizes of the box cross section), three kinds of uprights profiles (with a different thickness of the section walls), and two types of connectors (four-tab connectors and five-tab connectors). Flexural tests were carried out on 101 assemblies. For the assemblies containing the uprights having the thickness of 1.5 mm, the five-tab connector leads to a higher value of the capable moment and higher rotational stiffness than similar assemblies with four-tab connectors. A contrary phenomenon happens in case of the assemblies containing the upright profiles having a thickness of 2.0 mm regarding the capable design moment. It is shown how the safety coefficient of connection depends on both the rotational stiffness and capable bending moment.

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