6th order polynomial equation as pressure load

Adrunodro
Adrunodro Altair Community Member
edited April 2022 in Community Q&A

Hi,

I have fitted a 6th order polynomial to a set of points and I want to use it as a pressure equation on one face of a propeller blade. The exact equation i'm writing in the box next to equation is this one:
-1.0157e(-16)*y^6+1.0721e(-13)*y^5-4.1705e(-11)*y^4+6.6163e(-09)*y^3-2.5475e(-07)*y^2-8.5948e(-06)*y+1.2454e(-03)

which has a maximum value of 0.0036 in the interval (0,350)

My model is in mm, RHO=2.781e-9 and E=70,000 so I think using MPa is consistent but I get 0 displacement and 0 errors

what's the problem?

I'm attaching a screenshot with my pressure load settings

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Best Answer

  • Adriano Koga_20259
    Adriano Koga_20259 New Altair Community Member
    edited February 2021 Answer ✓

    try removing the ().

    -1.0157e-16*y^6+1.0721e-13*y^5-4.1705e-11*y^4+6.6163e-09*y^3-2.5475e-07*y^2-8.5948e-06*y+1.2454e-3

    image

Answers

  • Q.Nguyen-Dai
    Q.Nguyen-Dai Altair Community Member
    edited February 2021

    I have some issue with complicated equation too. Finally I have to write a small Tcl script to make pressure myself.

  • Adrunodro
    Adrunodro Altair Community Member
    edited February 2021

    I have some issue with complicated equation too. Finally I have to write a small Tcl script to make pressure myself.

    Thanks Q.Nguyen-Dai but that sound to me more like a problem than a solution ;)

  • Adriano Koga_20259
    Adriano Koga_20259 New Altair Community Member
    edited February 2021 Answer ✓

    try removing the ().

    -1.0157e-16*y^6+1.0721e-13*y^5-4.1705e-11*y^4+6.6163e-09*y^3-2.5475e-07*y^2-8.5948e-06*y+1.2454e-3

    image

  • Adrunodro
    Adrunodro Altair Community Member
    edited February 2021

    try removing the ().

    -1.0157e-16*y^6+1.0721e-13*y^5-4.1705e-11*y^4+6.6163e-09*y^3-2.5475e-07*y^2-8.5948e-06*y+1.2454e-3

    image

    Wonderful, Adriano. That solved my problem!

    Thank you both!

  • Vladimir Gantovnik_21974
    Vladimir Gantovnik_21974 Altair Community Member
    edited April 2022

    Is it possible to do it using tcl?