structural analysis
Structural Analysis Laboratory
EXPERIMENT NO. 1
Aim: - To verify strain in an externally loaded beam with the help of a strain gauge indicator and to verify theoretically.
Apparatus: - Strain gauge Indicator, weights, hanger, scale, verniar caliper.
Formula: - f = M y
I
Theory : - When a beam is loaded with some external loading, moment & shear force are set up at each strain. The bending moment at a section tends to deflect the beam & internal stresses tend to resist its bending. This internal resistance is known as bending stresses.
Following are the assumpsions in theory of simple bending.
1. The material of beam is perfectly homogeneous and isotropic (i.e. have same elastic properties in all directions.)
2. The beam material is stressed to its elastic limits and thus follows Hook’s law. 3. The transverse section which are plane before bending remains plane after bending also.
4. The value of young’s modulus of elasticity ‘E’ is same in tension and compression. The bending stress at any section can be obtained by beam equation. f = (M/I) y
Where, M= moment at considered section. f = extreme fiber stresses at considered section.
I = Moment of inertia at that section. y= Extreme fiber distance from neutral axis. fmax = maximum stress at the farthest fiber i.e. at ymax from neutral axis. Digital strain indicator is used to measure the strain in static condition. It incorporates basic bridge balancing network, internal dummy arms, an amplifier and a digital display to indicate strain value.
In resistance type strain gauge when wire is stretched elastically its length and diameter gets altered. This results in an overall change of resistance due to change in both the dimensions. The method is to measure change in resistance, which occurs as a result of change in the applied load.
Strain can be calculated analytically at the section by using Hook’s law. Distrainindicator is used to measure the extreme fiber at particular section. It
EXPERIMENT NO. 1
Aim: - To verify strain in an externally loaded beam with the help of a strain gauge indicator and to verify theoretically.
Apparatus: - Strain gauge Indicator, weights, hanger, scale, verniar caliper.
Formula: - f = M y
I
Theory : - When a beam is loaded with some external loading, moment & shear force are set up at each strain. The bending moment at a section tends to deflect the beam & internal stresses tend to resist its bending. This internal resistance is known as bending stresses.
Following are the assumpsions in theory of simple bending.
1. The material of beam is perfectly homogeneous and isotropic (i.e. have same elastic properties in all directions.)
2. The beam material is stressed to its elastic limits and thus follows Hook’s law. 3. The transverse section which are plane before bending remains plane after bending also.
4. The value of young’s modulus of elasticity ‘E’ is same in tension and compression. The bending stress at any section can be obtained by beam equation. f = (M/I) y
Where, M= moment at considered section. f = extreme fiber stresses at considered section.
I = Moment of inertia at that section. y= Extreme fiber distance from neutral axis. fmax = maximum stress at the farthest fiber i.e. at ymax from neutral axis. Digital strain indicator is used to measure the strain in static condition. It incorporates basic bridge balancing network, internal dummy arms, an amplifier and a digital display to indicate strain value.
In resistance type strain gauge when wire is stretched elastically its length and diameter gets altered. This results in an overall change of resistance due to change in both the dimensions. The method is to measure change in resistance, which occurs as a result of change in the applied load.
Strain can be calculated analytically at the section by using Hook’s law. Distrainindicator is used to measure the extreme fiber at particular section. It