Register Now

Login

Lost Password

Lost your password? Please enter your email address. You will receive a link and will create a new password via email.

$6–29$. Determine the force in members $HG$, $HE$ and $DE$ of the truss, and state if the members are in tension or  compression

$6–29$. Determine the force in members $HG$, $HE$ and $DE$ of the truss, and state if the members are in tension or compression

$6–29$. Determine the force in members $HG$, $HE$ and $DE$ of the truss, and state if the members are in tension or compression

6–29. Determine the force in members HG, HE and DE of the truss, and state if the members are in tension or compression

​$ \text{Step by Step Solution​} $

$ \text{Step 1: Problem Statement and Given Data} $

A truss structure is subjected to five vertical loads of $1500\,{\rm{lb}}$ each at points B, C, D, E, and F. The geometric parameters are:
\begin{array}{c}
{EF} = 3\,{\rm{ft}} \\
{GE} = 4\,{\rm{ft}}
\end{array}

$ \text{Step 2: Free Body Diagram and Objective} $

Construct the free body diagram for section EFG to analyze:

free body diagram of the truss part EFG.
\begin{array}{c}
\text{Member HG: } F_{HG} \\
\text{Member HE: } F_{HE} \\
\text{Member DE: } F_{DE}
\end{array}

$ \text{Step 3: Geometric Analysis and Angle Calculation} $

Determine the angle $\theta$ between member HE and horizontal:
\begin{array}{c}
\tan \theta = \frac{GE}{EF} = \frac{4\,{\rm{ft}}}{3\,{\rm{ft}}} \\
\theta = \tan^{-1}\left(\frac{4}{3}\right) \\
\hline
\theta \approx 53.1^\circ
\end{array}

$ \text{Step 4: Force in Member HG (Moment Equilibrium about E)} $

\begin{array}{c}
\sum M_E = 0 \\
F_{HG} \times GE – W_F \times EF = 0 \\
F_{HG} \times 4\,{\rm{ft}} – 1500\,{\rm{lb}} \times 3\,{\rm{ft}} = 0 \\
4F_{HG} = 4500\,{\rm{lb}\cdot{\rm{ft}}} \\
\hline
F_{HG} = 1125\,{\rm{lb}}\,(\rm{T})
\end{array}

$ \text{Step 5: Force in Member HE (Vertical Equilibrium)} $

\begin{array}{c}
\sum F_y = 0 \\
F_{HE} \sin \theta – W_E – W_F = 0 \\
F_{HE} \sin(53.1^\circ) – 1500\,{\rm{lb}} – 1500\,{\rm{lb}} = 0 \\
F_{HE} = \frac{3000\,{\rm{lb}}}{\sin(53.1^\circ)} \\
\hline
F_{HE} \approx 3751.5\,{\rm{lb}}\,(\rm{T})
\end{array}

$ \text{Step 6: Force in Member DE (Horizontal Equilibrium)} $

\begin{array}{c}
\sum F_x = 0 \\
-F_{HG} – F_{HE} \cos \theta – F_{DE} = 0 \\
-1125\,{\rm{lb}} – 3751.5\,{\rm{lb}} \times \cos(53.1^\circ) – F_{DE} = 0 \\
F_{DE} = -1125\,{\rm{lb}} – 2252.5\,{\rm{lb}} \\
\hline
F_{DE} = -3377.5\,{\rm{lb}}\,(\rm{C})
\end{array}

$ \text{Step 7: Verification and Summary} $

\begin{array}{c}
\text{Moment Equilibrium: } \sum M_E = 0 \quad \checkmark \\
\text{Force Balance: } \sum F_x = \sum F_y = 0 \quad \checkmark \\
\hline
\text{Final Results:} \\
\text{HG: } 1125\,{\rm{lb}}\,(\rm{T}) \\
\text{HE: } 3751.5\,{\rm{lb}}\,(\rm{T}) \\
\text{DE: } 3377.5\,{\rm{lb}}\,(\rm{C})
\end{array}

$ \text{Step 8: Conclusion} $

\begin{array}{c}
\text{The truss design satisfies equilibrium conditions with:} \\
\text{• HG in tension ($1125\,{\rm{lb}}$)} \\
\text{• HE in tension ($3751.5\,{\rm{lb}}$)} \\
\text{• DE in compression ($3377.5\,{\rm{lb}}$)}
\end{array}

MathJax Example

About AdminBeginner

Leave a reply

By commenting, you agree to the Terms of Service and Privacy Policy.