Lecture
| Calculation of a rod of a circular cross section for strength. |
| Strength analysis is performed using the torsional strength condition. |
| Firstly, it is necessary by calculation to determine the maximum shear stresses arising in a dangerous cross section. This calculation is made according to the formula: |
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| You must first determine the maximum torque M kr arising from the action of an external load. |
| Torque M kr characterizes the level of internal forces arising in the rod and counterbalancing the external load |
| The greater the value of M kr , the higher the level of internal forces arising in the rod. |
| The strength of the rod will determine the cross-section of the rod, in which the torque M kr has the maximum value. |
| The dimension of torque - M kr : kgms, kgm, Nm, kNm, etc. |
| After determining the maximum torque value, it is necessary to determine the cross-section characteristic, which determines the strength of a round rod in torsion, which is called the polar moment of resistance and is denoted by W p . |
Thus, the maximum shear stresses are determined.  which determine the strength of the rod, but do not give an answer to the question of whether the rod under consideration will withstand external load without destruction or not. |
To solve the problem, it is still necessary to know the allowable stresses.  versus maximum stress  and a decision is made on the strength or fragility of the calculated rod. |
| This is determined using the torsional strength condition. |
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| Thus, by comparing the maximum stresses arising in a dangerous section of a rod of circular cross-section c Allowed and decide on the strength of the rod. |
| Using the strength condition, it is possible to solve two problems: |
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Strength of materials
Terms: Strength of materials