Discussion
Consider the following statements about mode shapes.
1. They are orthogonal with respect to the mass matrix.
2. Their absolute magnitude is arbitrary and depends on the normalisation used.
3. The number of them equals the number of degrees of freedom.
Which are correct?
Answer: D
Correct answer: 1, 2 and 3
All three are correct. Mode shapes are orthogonal with respect to both the mass and stiffness matrices, which is what uncouples the equations of motion and makes modal superposition possible.
Their magnitude is arbitrary, since the eigenvalue problem is homogeneous, so a normalisation must be chosen - unit modal mass, or unit value at the roof. And the number of modes equals the number of degrees of freedom, the eigenvalue problem being of that order.
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development