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 Ante021 #1 Posted : 03 August 2022 14:27:48(UTC) Rank: NewbieGroups: Registered Joined: 03/08/2022(UTC)Posts: 3 Dear all, 1st off - I am new to SM and experienced this problem with simple structural stress equation (stress due to bending) that I am unable to resolve - see attached. Solver returns error "No real roots".I know there is as solution but I am unable to accomplish it. Q1: Please advise - what am I doing wrong?Q2: What is a best way to solve this as a system of equations (instead of substitution in order to arrive to a single eqn presented)? 5-6-14.sm (93kb) downloaded 17 time(s).Thanks!
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 alyles #2 Posted : 03 August 2022 16:52:12(UTC) Rank: Advanced MemberGroups: Registered Joined: 23/03/2016(UTC)Posts: 257Was thanked: 86 time(s) in 54 post(s) You can use units. Don't listen to Jean on this point. One solution - use maxima. 5-6-14.sm (96kb) downloaded 17 time(s). 5-6-14.pdf (564kb) downloaded 3 time(s). Feel free to join the SMath Studio Users Discord Channel: https://discord.gg/PayZpJW
 PompelmoTell #3 Posted : 03 August 2022 17:18:37(UTC) Rank: Advanced MemberGroups: Registered Joined: 23/12/2011(UTC)Posts: 311Location: italyWas thanked: 107 time(s) in 91 post(s) Considering the internal solutors of Smath, the only one who contains the units of measurement is "FindRoot". Otherwise there are all the solutors of the plugins (something has already been proposed to you for Maxima).Also careful not to fix "b" with a value, otherwise it is no longer an unknown for the solutor (For this, Clear ( b ) was used in the example with Maxima). 5-6-14-ser.sm (89kb) downloaded 21 time(s).sergioEdited by user 03 August 2022 17:22:31(UTC)  | Reason: Not specified
 Razonar #4 Posted : 03 August 2022 18:11:21(UTC) Rank: Advanced MemberGroups: Registered Joined: 28/08/2014(UTC)Posts: 1,169Was thanked: 682 time(s) in 426 post(s) Well, you have a solution with Maxima, another with FindRoot ... this is a solution with solve or roots. 5-6-14.sm (93kb) downloaded 31 time(s).Best regards.Alvaro.
 Kenny Lemens #5 Posted : 04 August 2022 01:34:46(UTC) Rank: Advanced MemberGroups: Registered Joined: 11/01/2018(UTC)Posts: 97Location: WisconsinWas thanked: 38 time(s) in 23 post(s) Greetings,There are several forums that discuss similar issues; I would encourage you to look though these threads:You will notice a lot of different approaches; I am personally bias to using maple to solve these problems (In order to run maple functions, you need to install the "Maple Tools Plugins" )[Using Maple]: Since you already constructed f( b ), all you need to do is perform a symbolic evaluation (keypress [Ctrl] + [.] instead of [=]). This will produce the following: . . . NOTE: you cannot have any of the variables defined, else those values will be treated as constants and thus substituted into the equation.You can copy the text below and paste it into your worksheet; this will generate the result based off of your variables (I work in imperial, thus 'ft' is referenced):Code:``{1143*((nthroot(L.1*(2*σ.a*(Q.m*σ.a+sqrt(Q.m*(Q.m*σ.a^2+γ^3*L.1^5)))+γ^3*L.1^5),3))^2+γ^2*L.1^4+γ*L.1^2*nthroot(L.1*(2*σ.a*(Q.m*σ.a+sqrt(Q.m*(Q.m*σ.a^2+γ^3*L.1^5)))+γ^3*L.1^5),3))}/{5000*σ.a*nthroot(L.1*(2*σ.a*(Q.m*σ.a+sqrt(Q.m*(Q.m*σ.a^2+γ^3*L.1^5)))+γ^3*L.1^5),3)*'ft}`` This brings us to units; by solving symbolically, you can identify those variables where the units "don't match". It looks like pressure is your culprit...I haven't had much success using pressure with regards to force; there is something with regards to the gravitational constant that doesn't quite work right. Therefore, I consider pressure to be of units force/area instead of mass/area. This will cause the units of your inputs to change as such: . . . I hope this Helps!-Kenny Lemens, P.E. "No matter where you go, there you are." -Buckaroo Banzai