The plastic hinge formed in a collapse mechanism are 4 and the indeter...
If the number of plastic hinges in the collapse mechanism are less than (r + 1) the collapse is called partial collapse. In such a case, part of the structure may fail making it useless as a whole. If the number of plastic hinges in the collapse mechanism are (r + 1) the collapse is called complete collapse. Such a mechanism has only one degree of freedom. If the number of plastic hinges developed are more than (r + 1), the collapse is called over complete collapse. In such a case there are two or more mechanisms for which the corresponding value of the load is the same, this load value being the actual coljapse load.
If the degree of indeterminacy is r, and the number of plastic hinges developed is N then,
N < (r + 1) Partial collapse
N = r + 1 Complete collapse .
N > r + 1 Overcomplete collapse
View all questions of this test
The plastic hinge formed in a collapse mechanism are 4 and the indeter...
Plastic Hinge:
A plastic hinge is a region in a structural element where plastic deformation occurs under loading. It is formed when the material reaches its yield point and undergoes significant permanent deformation. Plastic hinges play a crucial role in the collapse mechanism of structures.
Collapse Mechanism:
The collapse mechanism refers to the sequence of plastic hinges formed in a structure when it undergoes failure. It is the pattern of deformation that leads to the collapse of the structure. The number and locations of plastic hinges determine the collapse mechanism.
Indeterminacy:
Indeterminacy is a measure of the redundancy or excess support conditions in a structure. It represents the number of additional unknowns (reactions, displacements) that exist beyond what can be solved by applying equilibrium equations alone. Indeterminacy is typically denoted by the symbol "n" and can be calculated using the formula n = 3j - r, where "j" represents the number of joints and "r" represents the number of support reactions.
Analysis:
In this question, the plastic hinges formed are given as 4, and the indeterminacy is given as 3. We need to determine the collapse mechanism based on this information.
Plastic Hinges vs. Indeterminacy:
To understand the relationship between plastic hinges and indeterminacy, we can use the following rule:
- If the number of plastic hinges is equal to or less than the indeterminacy (n), the collapse mechanism is considered partial.
- If the number of plastic hinges is equal to the indeterminacy plus one (n + 1), the collapse mechanism is considered complete.
- If the number of plastic hinges is greater than the indeterminacy plus one (n + 1), the collapse mechanism is considered over complete.
- If the number of plastic hinges is less than the indeterminacy, the collapse mechanism is considered under complete.
Application to the Given Question:
In this case, the number of plastic hinges is 4, and the indeterminacy is 3. Applying the rule mentioned above:
- Number of plastic hinges = 4
- Indeterminacy (n) = 3
Since the number of plastic hinges (4) is equal to the indeterminacy plus one (3 + 1), the collapse mechanism is considered complete.
Therefore, the correct answer is option B: Complete.