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Ianasi A.C.,University Constantin Brancusi Of Tg Jiu
Advanced Materials Research | Year: 2014

Wood is a material of construction relatively inexpensive and easy to put into practice because of its lightness, reusability, simplicity in fabrication and environmental compatibility. However, its ability to lift load small compared to other building materials, it greatly limits the range of its use. Increasing the mechanical strength of wood elements used in construction is a goal that, once achieved, would expand the use of this material, with notable economic repercussions. The use of composite materials such as CFRP (carbon fiber reinforced plastic) as reinforcement for wood elements under bending loads like beams requires attention to the techniques of reinforcing for different layouts of CFRP elements. Each choice of reinforcing could potentially lead to different results. When the choice has been made, the next step is the selection of the most adequate CFRP elements. For this reason, selection of the reinforcement layout and material should be guided by an accurate analysis of the characteristics of the element to be reinforced in order to avoid ineffective interventions. The present paper is concerned with determination the performances of wood beams reinforced with CFRP composites by investigating their bending resistance and showing crushing damage in the bending region. All tested wood beams presented in paper were made from beech. The results for the un-reinforced beams are reported solely for the purpose of quantitatively evaluating the effectiveness of the interventions through a comparison with the results for CFRP strengthened beams. The technology of composite material reinforcement is based on using CFRP plates bonded with an epoxy resin on the wood beams. After bonding, the beams were tested to bending on a universal testing machine with a punctuated force placed at the middle of the beams. The results indicate that the behavior of reinforced beams with CFRP is totally different from that of un-reinforced one. During the performed tests, observations of the experimental load–displacement relationships showed that bending strength increased for wood beams reinforced with CFRP compared to those without CFRP reinforcement. Mechanical tests on the reinforced wood beams proved that CFRP materials produced flexural displacement and lifting increases of the beams that entitles us to say this kind of materials have improved the mechanical performances of tested wooden beams. © (2014) Trans Tech Publications, Switzerland.

Ionici C.,University Constantin Brancusi Of Tg Jiu
International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management, SGEM | Year: 2015

This paper presents attempts to tear and tear fracture of steels sintered iron powder with added molybdenum and carbon. Toughness values in the range 27,8-reach 38 MPa. There is a discontinuous crack propagation, fracture is ductile matrix base is easily observed pores transcrystalline and free. Hardness and toughness tests are performed on specimens pre-cracate, they give more information than specimens with notch. Units provide more targets for crack resistance of the material analyzed in comparison with notched specimens. Two grupe of test sample have been obtained from elemental and prealloyed powders. High temperatures sintering lead to increased resistance to mechanical testing of materials and crack propagation will be due to several microvolume between pores. Initial pore morphology changed continuously in the process of sintering. © SGEM2015.

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