Calculate all the mass-normalised modal vectors, Mechanical Engineering

The body, suspension and engine mounting system of a vehicle may be idealised as a three degree of freedom system consisting of a bar of mass 1400 kg and the centre of mass at G, 1 m from the front and 2 m from the rear ends as shown in the Figure Q1. The suspension system consists of springs and dampers, the front suspension consists of a spring of stiffness of kF = 25 kN/m and damper of damping coefficient c and the rear with stiffness of kR = 20 kN/m and damping coefficient of c. The moment of inertia of the vehicle about point G is1200 kgm2. The engine and its mount is idealised as mass-spring-damper attached to the vehicle at G to isolate the engine vibration transmitted to the vehicle, the engine has a mass of 400 kg, the isolator has stiffness kE= 10 kN/m  and damping coefficient of c.

(a)          Draw the free body diagrams of the system and show that the equation of motion for the undamped system is given by:

518_equation1.png

(b)  Use eigen functions in MATLAB to calculate all the mass-normalised modal vectors and associated undamped natural frequencies. Hence sketch the modeshapes illustrating the dynamic behaviour of the system. Use hand calculations wherever possible to verify the results obtained from MATLAB.

(c)   If the damping due to the suspension and engine mount isolator are to be included in the model, modify the equation of motion given in part (a) to include the damping matrix, use the damping coefficient c.

(d)  The engine produces a sinusoidal excitation force of magnitude 150 N at frequency of 30 Hz, further excitation forces from the road are in the form of unit impulses applied to the front and rear ends of the vehicle, using Modal Analysis calculate the response of the system at the front suspension. using MATLAB plot the response in time domain. Assume a damping ratio of 0.1 for all modes.

(e)  Calculate one Frequency Response Function in Inertance form and plot it in the frequency range of interest using MATLAB.

Include all your MATLAB outputs and label them clearly. State all the necessary assumptions clearly. You may Export the MATLAB plots into word documents.

749_MATLAB.png

Posted Date: 2/19/2013 7:37:11 AM | Location : United States







Related Discussions:- Calculate all the mass-normalised modal vectors, Assignment Help, Ask Question on Calculate all the mass-normalised modal vectors, Get Answer, Expert's Help, Calculate all the mass-normalised modal vectors Discussions

Write discussion on Calculate all the mass-normalised modal vectors
Your posts are moderated
Related Questions
Calculate the KIC from the data - thick cylinder: In a fracture test a 3-point bend specimen of thickness 20 mm and depth 25 mm is supported over a span of 100 mm. The specime

(a) Split up the harmonic x = 8 sin(ωt + 45°), into two harmonic motions, one of which has amplitude of 10 and phase difference zero. (a) A body is subjected to two harmonic mot

(a) What will happen if air filter is not used? (b) What are the components of an air filter? (c) What precautions should be followed while cleaning the air filter? (d) What grade

Pattern Practices - Manufacturing processes: Pattern Practices : A pattern may be defined as a replica or fascimile model of the desired casting which, when packed or embedd


Find out the proof load in close coiled helical spring: A close coiled helical spring is built of 6 mm diameter wire. The coil diameter is equal to 80 mm, number of coil is 10

In most hardware stores, you can find what has known as a Heat Gun. Hold the heat gun about 6 inches away from the acrylic you intend on bending say the bumper on a car. They are p

Explain the process of a Pneumatic Proportional Controller and get its transfer function. What modification is needed to make it function as a proportional plus derivative controll

I am attending Thermodynamics class at the university. The professor asked me to write a research on Renewable Energy: Solar Power. The report should be of 10 pages and at least 10

An airfoil of surface area 1.5 ft2 is tested for lift L in a wind tunnel. At an angle of attack of 7° with standard air of density 0.0024 slugs/ft3 at a speed of 90 ft/sec, the lif