Poisson's ratio - Revision history

Joceil.infante at 07:05, 3 October 2017

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Joceil.infante: Created page with "Poisson ratio is one of the important criteria to be considered in pipe selection where the system may be subjected to sub-atmospheric pressure (e.g. Siphonic drainage syste..."

2017-10-03T01:49:15Z

Created page with "Poisson ratio is one of the important criteria to be considered in pipe selection where the system may be subjected to sub-atmospheric pressure (e.g. Siphonic drainage syste..."

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Poisson ratio is one of the important criteria to be considered in pipe selection where the system may be subjected to sub-atmospheric pressure (e.g. [[Siphonic drainage systems]]). In general, a lower value in Poisson ratio provides better strength against collapse of pipe due to sub-atmospheric pressure.

In evaluating the limiting or maximum pressures, forces and deflections on plastic pipe, fittings and components covered by this standard, the material properties listed in Table 8.1 are assumed at an operating temperature of 20°C (68°F).

{| class="wikitable"
!colspan="6"|Table 8.1: Material Properties at an Operating Temperature of 20°C (68°F)
|-

@@ Line 46: / Line 46: @@
 |ASTM D696
 |}
 Calculation of allowable pressure <math>(Pa)</math>: The minimum required pipe wall thickness <math>(t)</math> shall be based on '''Equations 8.1''' and '''8.2''' in '''Table 8.2''' and the mechanical and dimensional properties of the pipe material evaluated. '''Equations 8.1''' and '''8.2''' apply for a long cyclindrical tube of length '''L''' and wall thickness '''t''' under uniform external pressure with <math>(R/t) /> 10</math>.
@@ Line 91: / Line 96: @@
 * '''Poisson's ratio''' describes the relative change of the lateral dimension of an object when the load is applied on the longitudinal direction and vice versa. (See reference video link [https://www.youtube.com/watch?v=hBnzrBhnzVo])
 == References ==

@@ Line 64: / Line 64: @@
 |}
 <br clear=all>
-The parameter <math>E_c</math> is the elastic creep modulus at the specified time of loading. The allowable pressure <math>(Pa)</math> shall be the calculated critical buckling pressure divided by the factor of safety (FS) as in equation below:
+The parameter <math>E_c</math> is the elastic creep modulus at the specified time of loading. The allowable pressure <math>(Pa)</math> shall be the calculated critical buckling pressure divided by the factor of safety ('''FS''') as in equation below:
 '''Equation 8.3:'''
@@ Line 71: / Line 71: @@
 <math> P_a = \frac{P_cr}{FS} \ge 14.7 psia (1.0 bar)</math>
 <br clear=all>
 Poisson's ratio is
-*the ratio of the relative contraction strain (or transverse strain) normal to the applied load - to the relative extension strain (or axial strain) in the direction of the applied load <ref>http://www.engineeringtoolbox.com/poissons-ratio-d_1224.html</ref>
 Poisson's Ratio can be expressed as;
@@ Line 89: / Line 90: @@
      μ = Poisson’s Ratio (dimensionless)
-* Describes the relative change of the lateral dimension of an object when the load is applied on the longitudinal direction and vice versa. (See reference video link [https://www.youtube.com/watch?v=hBnzrBhnzVo])
+* '''Poisson's ratio''' describes the relative change of the lateral dimension of an object when the load is applied on the longitudinal direction and vice versa. (See reference video link [https://www.youtube.com/watch?v=hBnzrBhnzVo])
 == References ==

@@ Line 71: / Line 71: @@
 <math> P_a = \frac{P_cr}{FS} \ge 14.7 psia (1.0 bar)</math>
 <br clear=all>
 == References ==

@@ Line 1: / Line 1: @@
 Poisson ratio is one of the important criteria to be considered in pipe selection where the system may be subjected to sub-atmospheric pressure (e.g. [[Siphonic drainage systems]]). In general, a lower value in Poisson ratio provides better strength against collapse of pipe due to sub-atmospheric pressure.
-In evaluating the limiting or maximum pressures, forces and deflections on plastic pipe, fittings and components covered by this standard, the material properties listed in Table 8.1 are assumed at an operating temperature of 20°C (68°F).<ref> ASPE Standard 45 </ref>
+In evaluating the limiting or maximum pressures, forces and deflections on plastic pipe, fittings and components covered by this standard, the material properties listed below are assumed at an operating temperature of 20°C (68°F).<ref> ASPE Standard 45 </ref>
 {| class="wikitable"
-!colspan="6"|Table 8.1:Material Properties at an Operating Temperature of 20°C (68°F)
+!colspan="6"|Material Properties at an Operating Temperature of 20°C (68°F)
 |-
 |'''Property/ Material'''
@@ Line 52: / Line 52: @@
 !colspan="6"|Table 8.2 Pipe Wall Thickness Calculations
 |-
-|Equation 8.1 <br clear=all>
+|'''Equation 8.1''' <br clear=all>
 When, <math> L \ge 4.9R \sqrt{\frac{R}{t}}</math>
-|Equation 8.2 <br clear=all>
+|'''Equation 8.2''' <br clear=all>
 When <math> L \le 4.9R \sqrt{\frac{R}{t}}</math>
 |-
@@ Line 66: / Line 66: @@
 The parameter <math>E_c</math> is the elastic creep modulus at the specified time of loading. The allowable pressure <math>(Pa)</math> shall be the calculated critical buckling pressure divided by the factor of safety (FS) as in equation below:
-'''Equation 8.3:''' <br clear=all>
+'''Equation 8.3:'''
 <math> P_a = \frac{P_cr}{FS} \ge 14.7 psia (1.0 bar)</math>
 == References ==

@@ Line 47: / Line 47: @@
 |}
-Calculation of allowable pressure <math>(Pa)</math>: The minimum required pipe wall thickness <math>(t)</math> shall be based on Equations 8.1 and 8.2 in Table 8.2 and the mechanical and dimensional properties of the pipe material evaluated. Equations 8.1 and 8.2 apply for a long cyclindrical tube of length L and wall thickness t under uniform external pressure with (R/t) > 10.<ref> ASPE Standard 45 Cl.8.3.9 </ref>
+Calculation of allowable pressure <math>(Pa)</math>: The minimum required pipe wall thickness <math>(t)</math> shall be based on '''Equations 8.1''' and '''8.2''' in '''Table 8.2''' and the mechanical and dimensional properties of the pipe material evaluated. '''Equations 8.1''' and '''8.2''' apply for a long cyclindrical tube of length '''L''' and wall thickness '''t''' under uniform external pressure with <math>(R/t) /> 10</math>.
 {| class="wikitable"
 !colspan="6"|Table 8.2 Pipe Wall Thickness Calculations
 |-
-|Equation 8.1 When <math> L \ge 4.9R \sqrt{\frac{R}{t}}</math>
+|Equation 8.1 <br clear=all>
-|Equation 8.2 When <math> L \le 4.9R \sqrt{\frac{R}{t}}</math>
+When, <math> L \ge 4.9R \sqrt{\frac{R}{t}}</math>
 |-
-|<math>P_{cr}= \frac{E_c}{3(1-\mu^2)} \Big[ \frac{t}{R} \Big]^3</math>
+|<math>P_{cr}= \frac{E_c}{3(1-\mu^2)} \Bigg[ \frac{t}{R} \Bigg]^3</math>
 |}
 <br clear=all>
 == References ==