Understanding a 2DOF Problem with One Mass: Help Needed with Setting Up Matrices

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In summary, the problem involves finding the natural frequencies, damping ratios, and mode shapes of a system with parameters m=5, k1=100, k2=150, and c=2. The student has attempted to set up the problem twice but is unsure of the correct approach as they have only seen multiple degree of freedom problems with more than one mass and all springs at 90 degree angles. They are struggling with setting up the M, K and C matrices and have received non-real eigenvalues in their attempts. They are seeking help with correctly setting up the problem.
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Homework Statement


I need some help with the following problem:

System shown has m=5, k1=100, k2=150, and c=2

Find the natural frequencies, damping ratios, and mode shapes.

The figure of the system has been attached.

2. Known Equations
I know how to find natural frequencies, damping ratios, and mode shapes, my only issue is actually setting up the M, K and C matrices as I have only seen multiple degree of freedom problems with more than one mass, and with all of the springs at 90 degree angles. I am not sure how I am supposed to work this one out.3. Work attempted
I have attempted at setting up this problem twice but I know I am doing it wrong because when I calculate my M^-.5*K*M^-.5 Matrix it does not exist, or it gives me non real numbers as eigenvalues (eg. x=42.6 + or - 17.2603i). Any help setting up the problem would be appreciated.
 

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Thanks.Homework EquationsM= mass matrix, K= stiffness matrix, C= damping matrixThe Attempt at a SolutionI am not sure how to set up this problem or what matrices I should be using. I have tried twice but both times the eigenvalues are non real numbers so I know I am doing it wrong. Any help would be appreciated. Thanks.
 

FAQ: Understanding a 2DOF Problem with One Mass: Help Needed with Setting Up Matrices

What is the 2DOF problem with one mass?

The 2DOF problem with one mass refers to a system with two degrees of freedom (2DOF) where one of the masses is fixed. This means that the system can move in two different directions, but only one of these movements is affected by the mass.

How is the 2DOF problem with one mass represented mathematically?

The 2DOF problem with one mass is represented by a set of differential equations that describe the motion of the system. These equations take into account the mass, stiffness, and damping of the system, as well as any external forces acting on it.

What are the main applications of the 2DOF problem with one mass?

The 2DOF problem with one mass has many practical applications, such as in mechanical engineering, aerospace engineering, and robotics. It is commonly used to model and analyze the behavior of systems with two degrees of freedom, such as suspension systems, vibration isolators, and robotic arms.

What are the solutions to the 2DOF problem with one mass?

The solutions to the 2DOF problem with one mass depend on the specific parameters and initial conditions of the system. Generally, these solutions involve finding the natural frequencies, mode shapes, and response amplitudes of the system. These can be calculated analytically or through numerical methods.

How does the 2DOF problem with one mass differ from other types of problems with multiple degrees of freedom?

The 2DOF problem with one mass is a specific case of a more general problem with multiple degrees of freedom. In this particular case, one of the masses is fixed, which simplifies the equations and reduces the complexity of the problem. However, the principles and methods used to solve the 2DOF problem can be applied to other problems with multiple degrees of freedom.

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