The main aim of this paper is to present a Stochastic Finite Element Method analysis with reference to principal design parameters of bridges for pedestrians: eigenfrequency and deflection of bridge span. They are considered with respect to random thickness of plates in boxed-section bridge platform, Young modulus of structural steel and static load resulting from crowd of pedestrians. The influence of the quality of the numerical model in the context of traditional FEM is shown also on the example of a simple steel shield. Steel structures with random parameters are discretized in exactly the same way as for the needs of traditional Finite Element Method. Its probabilistic version is provided thanks to the Response Function Method, where several numerical tests with random parameter values varying around its mean value enable the determination of the structural response and, thanks to the Least Squares Method, its final probabilistic moments.
In this paper a technique has been developed to determine constant parameters of copper as a power-law hardening material by tensile test approach. A work-hardening process is used to describe the increase of the stress level necessary to continue plastic deformation. A computer program is used to show the variation of the stress-strain relation for different values of stress hardening exponent, n and power-law hardening constant, α . Due to its close tolerances, excellent corrosion resistance and high material strength, in this analysis copper (Cu) has been selected as the material. As a power-law hardening material, Cu has been used to compute stress hardening exponent, n and power-law hardening constant, α from tensile test experiment without heat treatment and after heat treatment. A wealth of information about mechanical behavior of a material can be determined by conducting a simple tensile test in which a cylindrical specimen of a uniform cross-section is pulled until it ruptures or fractures into separate pieces. The original cross sectional area and gauge length are measured prior to conducting the test and the applied load and gauge deformation are continuously measured throughout the test. Based on the initial geometry of the sample, the engineering stress-strain behavior (stress-strain curve) can be easily generated from which numerous mechanical properties, such as the yield strength and elastic modulus, can be determined. A universal testing machine is utilized to apply the load in a continuously increasing (ramp) manner according to ASTM specifications. Finally, theoretical results are compared with these obtained from experiments where the nature of curves is found similar to each other. It is observed that there is a significant change of the value of n obtained with and without heat treatment it means the value of n should be determined for the heat treated condition of copper material for their applications in engineering fields.
Structure Damping Section, pp.48-87.
Sasikumar K.S.K., Selvakumar S. and Arulshri K.P. (2011): An analysis of the effect of constraining layer modulus on the vibration control of beams treated with PCLD. - European Journal of Scientific Research, vol.66, No.3, pp.377-391.
Yan M.J. and Dowell E.H. (1972): Governing equations for vibrating constrained layer damping of sandwich beams and plates. - J. Appl. Mech. Trans. ASME, vol.94, No., pp.1041-1047.
Salima Sadat, Allel Mokaddem, Bendouma Doumi, Mohamed Berber and Ahmed Boutaous
good mechanical properties at break and must first be plasticized or formulated with different additives. Starchy materials can then be implemented by casting or extrusion [ 5 , 6 ]. For this reason, we thought of strengthening a Starch matrix by two natural fibers–Hemp and Sisal.
Sisal is a perennial plant consisting of a rosette of large leaves with triangular section up to 2 m long. It is a tropical plant and each plant can produce 180 to 240 leaves depending on the geographical situation, altitude, rainfall and variety considered. Sisal can be harvested in 2
Dmitry Popolov, Sergey Shved, Igor Zaselskiy and Igor Pelykh
point for a cantilever beam of rectangular cross-section under the action of a static transverse bending force in accordance with [ 7 ] has the form of:
f C x = − P x max L 3 3 E I y = − P x max 4 L 3 E H h 3 f C y = − P y max L 3 3 E I x = − P y max 4 L 3 E H 3 h ,
where E is the Young’s modulus for the material of the elastic element
the global behavior of the part may not be easily determined.
Different ways of improving the mechanical behavior of engineering parts are used in practice. One of them goes through selecting a material having higher Young’s modulus value. The other is to modify the inertia moment of a considered part [ 1 , 2 ]. This can be achieved by inserting ribs in the longitudinal and/or transversal directions and/or webbing. If reinforcements are oriented in the normal direction as of the longitudinal ( z -axis) direction, it appears to be effective under bending loads, as
Amit K. Thawait, Lakshman Sondhi, Shubhashis Sanyal and Shubhankar Bhowmick
function, exponential function and Mori–Tanaka scheme. These distributions are implemented in the FEM using element based material grading. A finite element formulation for the problem is reported, which is based on the principle of stationary total potential. Disks are subjected to centrifugal body load and have clamped-free boundary condition. The work aims to investigate the effect of grading parameter “ n ” on the deformation and stresses for different material gradation law.
In this section, geometric equations as well as different
von Mises stress at mid-section of drill bit.
von Mises stress at entry without drill bit.
von Mises stress at completion of drilling.
The simulation that ran on an Intel second-generation mobile processor took approximately 2 days to complete. Subsequent models were created with only change in drill bit diameter. The simulation in whole with consideration of subsequent models took approximately around 8 to 16 days. The stable time increment is
S. Sai Venkatesh, T. A. Ram Kumar, A. P. Blalakumhren, M. Saimurugan and K. Prakash Marimuthu
( y )
Area moment of inertia of section ( I ) is given by ( bh 3 /12)
3.25521 × 10 -8 m 4
Sectionmodulus ( Z ) is given by ( I/y )
2.60417 × 10 –6 m 3
Young’s modulus of tool holder (E)
2.05 × 10 11 N/m 2
Distance from tool tip to center of strain gauge
Work piece diameter
The cutting force in turning operation is determined using a strain gauge. Here, the strain gauges are connected in half-bridge configuration type II. This configuration was specifically designed for measuring bending
specimens of type IV ( Figure 2 ): thickness T = 6 mm, width of narrow section W c = 6 mm, length of narrow section L = 33 mm, width overall W o = 19 mm, length overall L o = 100 mm, gage length G = 25 mm, distance between grips D = 65 mm, outer radius R o = 25 mm, and radius of fillet R = 14 mm. The mechanical tests were carried out with a Zwick/Roell-type machine with a capacity of 20 kN [ 9 ].
Specimens of uniaxial tensile test UT
All dimensions of the specimens are taken according to ASTM standard D638-03 [ 10 ]. The