SK04A Struktur Kayu Contoh soal Truss Part 1

Summary

This engineering tutorial covers the detailed process of analyzing forces, reactions, and load calculations in a structural framework. It explains the steps to determine the angles of force projections, equilibrium equations for reactions at supports, and the calculation of forces in structural members. The tutorial emphasizes determining whether the members experience tension or compression, calculating moments, and using geometry for force distribution. Finally, the analysis concludes with identifying the maximum tension and compression forces on the structure, followed by a stress evaluation for each member. A comprehensive guide for structural analysis enthusiasts.

Takeaways

• 😀 The analysis begins with understanding the reactions at the joints and identifying the types of supports in the structure (e.g., pin joint and roller).
• 😀 The angle 'alpha' (α) is calculated using trigonometric principles based on the triangle's sides, and is determined to be 36.87°.
• 😀 The structure involves projecting forces onto the Cartesian axes (x and y), which allows for calculating the components of the forces acting on the structure.
• 😀 The next step is to perform static equilibrium analysis by applying the equations of equilibrium (ΣFx = 0, ΣFy = 0, ΣM = 0) to solve for unknown reactions.
• 😀 After determining the reactions at the supports (AX = -60 kN, Ay = 48.75 kN, D = 31.25 kN), the analysis proceeds to the internal forces in the members.
• 😀 The internal forces in the structure are then calculated using methods like joint analysis to determine whether members are in tension or compression.
• 😀 The member forces are calculated step-by-step by analyzing forces in each direction, utilizing projection and equilibrium equations.
• 😀 The force in each member (e.g., FCD, FDF, FFG) is calculated, with the sign indicating whether the force is in tension (positive) or compression (negative).
• 😀 Zero force members are identified in the structure, which do not carry any load, simplifying the overall analysis.
• 😀 Finally, the maximum forces in the members are determined (e.g., the maximum tensile force is 83.33 kN, and the maximum compressive force is 52.08 kN), and these values are used to assess the material's safety against tension and compression stresses.

Q & A

What is the main task in the video script?

The main task is to analyze and solve a structural problem, specifically determining the forces in various members of a structure and checking whether the material is safe under tensile and compressive stresses.

What does the term 'alpha' (α) refer to in the context of this analysis?

Alpha (α) refers to an angle in the structure, which is determined based on the dimensions of the triangle formed by the structure's geometry. It is calculated using the sine function.

How is the angle α calculated in the script?

The angle α is calculated by using the formula α = arcsin(0.6), where 0.6 is the ratio of the height to the hypotenuse of the right triangle. The result is α = 36.87 degrees.

What is the significance of the forces 25 kN, 50 kN, and 25 kN in the analysis?

These forces represent external loads acting on the structure. The forces are then projected onto the Cartesian axes (X and Y directions) to be used in further calculations.

What is the purpose of performing the reaction analysis in this scenario?

The reaction analysis, involving Sigma FX, Sigma FY, and Sigma moment equations, is performed to find the unknown reactions at the supports of the structure. This is essential for determining the internal forces in each structural member.

Why does the analysis involve projecting the forces into the Cartesian coordinate system?

The forces are projected onto the Cartesian coordinate system to simplify their analysis and to break them down into components along the X and Y axes. This allows for easier calculation of the equilibrium conditions.

What is the formula used for moment equilibrium (Sigma M) in the script?

The moment equilibrium equation (Sigma M) is calculated by multiplying the force by the distance from the point of interest. The moments are then summed and set equal to zero to solve for unknown reactions.

How is the zero-force member concept applied in the script?

The zero-force member concept is used to identify structural members that do not carry any internal force. These members do not contribute to the overall force equilibrium of the structure and are set to zero in the calculations.

What does the script indicate about the forces acting on the different members of the structure?

The script calculates the internal forces in each member, indicating whether each member is under tension or compression. The forces are categorized as tensile or compressive based on their direction relative to the member's axis.

How are the final results used to assess the safety of the structure?

The final results, including the calculated forces and internal stresses in the members, are used to check whether the tensile and compressive stresses are within safe limits for the material, ensuring the structural safety of the system.