Is This Civil Engineering PDE Linear?

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Discussion Overview

The discussion centers around the linearity of a partial differential equation (PDE) that models the motion of frame members in civil engineering, particularly focusing on materials with different moduli in tension and compression. Participants explore the equation's structure, its boundary conditions, and the challenges associated with solving it, including the implications of variable coefficients.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant asks whether the given PDE is linear and requests assistance in solving it, providing the equation and boundary conditions.
  • Another participant suggests improving the formatting of the equation for clarity, referencing a resource on LaTex typesetting.
  • A participant asserts that the PDE is linear but notes that due to the implicit nature of EI(x,t) and m(x,t), an analytical solution is not feasible, implying that numerical methods may be necessary.
  • There is a reiteration of the equation for clarity, with a participant emphasizing the importance of adhering to forum standards for readability.
  • One participant inquires about recommended literature for solving nonlinear integro-differential equations, indicating a broader interest in related mathematical topics.
  • A later post requests the solution to the governing linear PDE, expressing gratitude in advance for any assistance provided.

Areas of Agreement / Disagreement

There is a disagreement regarding the feasibility of solving the PDE analytically, with some participants suggesting it is linear while others emphasize the challenges posed by the variable coefficients. The discussion remains unresolved regarding the best approach to solving the equation.

Contextual Notes

The discussion highlights the complexity of the PDE due to the dependence of coefficients on variables, which may affect the methods of solution. The implications of boundary conditions and the nature of the coefficients are not fully explored, leaving open questions about their impact on the solution process.

omarxx84
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can anyone help me to solve this equation ?. is this equation linear or not?
knowing, this equation represents the equation of motion for frame members for materials which have different moduli in tension and compression (civil engineering).
"EI" ("x,t" ) ("∂" ^"4" "u" ("x,t" ))/〖"∂x" 〗^"4" "-N" ("x" ) ("∂" ^"2" "u" ("x,t" ))/〖"∂x" 〗^"2" "+m" ("x,t" ) ("∂" ^"2" "u" ("x,t" ))/〖"∂t" 〗^"2" "=0"
In which,
EI depends on a roots of cubic equation, and t depends on ("∂" ^"2" "u" )/〖"∂t" 〗^"2" (acceleration)
boundary conditions:
at x=0, u=0 and at x=L, u=0
at t=0, u=0
 
Last edited:
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That's too messy to read. Go to the "Math and Science Learning Material" sub-forum above, and look at "Introducing LaTex typesetting thread to see about formatting math for the forum. For example:

\frac{\partial u}{\partial t}=\frac{\partial^2 u}{\partial x^2}

Click on the equation to see the code used to generate it.
 
EI(x,t) (∂^4 u(x,t))/〖∂x〗^4 -N (∂^2 u(x,t))/〖∂x〗^2 +m(x,t) (∂^2 u(x,t))/〖∂t〗^2 =0
please, try to read, then help me to solve it.
 
Yes, the PDE is linear.
Since EI(x,t) and m(x,t) are not explicit, the equation cannot be analitically solved.
Even if EI(x,t) and m(x,t) were explicit, but probably not simple formulas, the equation couldn't be analitically solved in the general case.
Probably, numerical calculus is the only way.
 
omarxx84 said:
EI(x,t) (∂^4 u(x,t))/〖∂x〗^4 -N (∂^2 u(x,t))/〖∂x〗^2 +m(x,t) (∂^2 u(x,t))/〖∂t〗^2 =0
please, try to read, then help me to solve it.

i think when posting to a forum it is courteous to abide by their standards or requests. it reflects much better on you if you show that you've taken the time to make the question easier to read or more understandable, which will further add to people's willingness to help you.

replying to someone by saying no i won't work on making it easier to read, you should try harder, usually won't get you anywhere.
 
what is the best books or papers for solving nonlinear integro-differential equations??
 
please...What is the solution of the governing linear partial differential equation, with variable coefficients, of motion attached in the attached file. and i will be very grateful for you...
 

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