geometrical profile (roughness) of joint surfaces influences the behaviour of rock joints under shear loading. with regard to the dilation, there are two models of direct shear test that may simulate the original loading condition existing in the location from where the specimens have been sampled. the first model in which the normal load is constant (cnl) and the discontinuity is free to dilat...

Being physical mechanical parameters of joints, normal and shear stiffnesses are indispensable components the numerical simulation theoretical analysis behavior joints. The objective this work is to put forward an experimental method determine joint stiffness under constant load (CNL) conditions. For purpose, closure direct tests CNL conditions were conducted. Normal was determined by ratio str...

in this work, homogeneous thermochemical co-precipitation method was used to fabricate w-25wt%cu nanocomposite. synthesized nanocomposite powder was calcined and reduced. a hydrogen atmosphere sintering at 1200oc for 105 consolidated the product up to a density close to 98% theoretical density. wear experiment were carried out using a pin-ondisc set up at three normal loads of 5, 10 and 15 n an...

In this work, homogeneous thermochemical co-precipitation method was used to fabricate W-25wt%Cu nanocomposite. Synthesized nanocomposite powder was calcined and reduced. A hydrogen atmosphere sintering at 1200oC for 105 consolidated the product up to a density close to 98% theoretical density. Wear experiment were carried out using a pin-ondisc set up at three normal loads of 5, 10 and 15 N an...

In this work, homogeneous thermochemical co-precipitation method was used to fabricate W-25wt%Cu nanocomposite. Synthesized nanocomposite powder was calcined and reduced. A hydrogen atmosphere sintering at 1200oC for 105 consolidated the product up to a density close to 98% theoretical density. Wear experiment were carried out using a pin-ondisc set up at three normal loads of 5, 10 and 15 N an...

springs are the  mechanical parts which have many application in industries. static and dynamic forces cause relaxation in these parts so that they lose some of their free length and reaction force. springs constant are very important in airplane and vailway industry since constant and variable forces are applied to them in period time, therefore it is necessary to avoid decreasing in spring co...