Recent content by mathmate

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    Concrete bridge pier formwork design

    For the setting part, there is usually a limit of how high the concrete can be poured at any one time. The hydrostatic pressure can be calculated based on this height. If the concrete is in fact poured continuously to the top, some sort of estimate of the concrete setting can be applied, but...
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    Concrete bridge pier formwork design

    As a first approximation, you would consider fresh concrete as a viscous fluid with a density 2.5 times that of water. So hydrostatic pressure (increases with depth) is a primary consideration. The spacing of fasteners of the two halves has to be looked at, as well as local deformation. Since...
  3. M

    Trussel buckling,question from mechanics of materials

    As a starter, I suggest you analyze the structure to find, step 1: for each member of the truss, calculate maximum force without buckling - magnitude of the force - magnitude of the stress - direction of the force (compression or tension) - the maximum value of F that will keep the...
  4. M

    Fixed-point iteration method to find an approximation

    There is no iteration in x=(25)^(1/3) so the calculator simply evaluated the expression and gave the answer. x needs to be on the right hand side to initiate iterations (e.g. x0=2) if x=5/sqrt(5) does not satisfy the [2,3] interval conditions, you'll need to find other functions such as...
  5. M

    Fixed-point iteration method to find an approximation

    OK, use Xn+1=5/sqrt(Xn), but you can use a=2.8, a^3=21.952 b=3, b^3=27 then 5/sqrt(a)=2.988<3 and 5/sqrt(b)=2.886...>2.8
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    Fixed-point iteration method to find an approximation

    Newton's works very well when we put f(x)=x^3-25 It converges to 2.924017738212866 in 7 iterations starting with x0=2, and in 5 starting with x0=3.
  7. M

    Fixed-point iteration method to find an approximation

    Can you describe what is a "fixed point iteration" as you understand it? I see it as an iterative function F(x) such that Xn+1 = F(Xn) similar to Newton's method which eventually gives a value very close to the required solution. See also: http://en.wikipedia.org/wiki/Fixed_point_iteration
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    What is the formula for bending moment of a beam subjected to UDL and a point load?

    As per my previous response: "A centrally loaded column not subject to lateral loads does not incur first order bending moments. Second and higher order bending moments could be caused by lateral buckling or deflections (P-delta effects)." Is the column monolithic with other structures...
  9. M

    What is the formula for bending moment of a beam subjected to UDL and a point load?

    Maximum positive bending moment at the centre of wL^2/24 is correct for a fixed-fixed beam. If you are doing the design of a beam, do not forget that the negative support moments of wL^2/12 are higher than that at the centre. Draw the bending moment diagram would make it clear.
  10. M

    What is the formula for bending moment of a beam subjected to UDL and a point load?

    rock.freak667 will have to interpret the application of his formula. wL^2/8 is the maximum BM at the centre of a udl of w kg/m for a simply supported beam. In fact, all these questions about formulas can be resolved by standard tables available in books or the web, such as...
  11. M

    What is the formula for bending moment of a beam subjected to UDL and a point load?

    For a horizontal simply supported beam of length L subject to udl w, the maximum bending moment is at the centre and equal to wL^2/8 distributed along the span parabolically. For a horizontal simply supported beam of length L, and subject to a point load P at mid-span, the maximum bending...
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    Fortran Fortran Forum

    It depends how your data are arranged. If the data files are named in a systematic way, it is easy to process them one by one. See post#124 of this thread (on page 8) for an example. If your data file is generated on the fly in Unix, and you have a script to run the fortran program immediately...
  13. M

    Project Euler problem 3

    for(BigInt y = x/2; y>2; --y) Just a suggestion: since the largest prime factor of x cannot not exceed x0=(int)sqrt(x), it pays to start at x0, especially for large numbers.
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    Fortran Fortran Forum

    For Lanz, try the following link: http://www.cse.yorku.ca/~roumani/fortran/ftn.htm and see if you could find anything here: http://www.thefreecountry.com/compilers/fortran.shtml For Anglea, Since you are looking for the detailed usage of a Unix command "find -name....", you may want to make a...
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    Fortran Fortran77: Data I/O in big file

    It depends on how you use the file. If it is a huge stiffness matrix which you have to read from A-Z, then you do not have too many options. If it is a file from which you extract information ("I only need a few data points during the calculations"), then you may seriously consider using the...
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