HP 48gII hp 48gII_user's manual_English_E_HDPMSG48E67_V2.pdf - Page 219

The solution can be seen from within the SOLVE EQUATION input form by pressing @EDIT while the ex: field is highlighted. The resulting value is 2.470833333333E-3. Press @@@OK@@ to exit the EDIT feature. Suppose that you now, want to determine the Young's modulus that will produce a strain of exx = 0.005 under the same state of stress, neglecting thermal expansion. In this case, you should enter a value of 0.005 in the ex: field, and a zero in the ∆T: field (with ∆T = 0, no thermal effects are included). To solve for E, highlight the E: field and press @SOLVE@. The result, seeing with the @EDIT feature is, E = 449000 psi. Press @SOLVE@ ` to return to normal display. Notice that the results of the calculations performed within the numerical solver environment have been copied to the stack: Also, you will see in your soft-menu key labels variables corresponding to those variables in the equation stored in EQ (press L to see all variables in your directory), i.e., variables ex, ∆T, α, σz, σy, n, σx, and E. Example 2 - Specific energy in open channel flow Specific energy in an open channel is defined as the energy per unit weight measured with respect to the channel bottom. Let E = specific energy, y = channel depth, V = flow velocity, g = acceleration of gravity, then we write E = y+V2. 2g The flow velocity, in turn, is given by V = Q/A, where Q = water discharge, A = cross-sectional area. The area depends on the cross-section used, for example, for a trapezoidal cross-section, as shown in the figure below, A = (b+m⋅y) ⋅y, where b = bottom width, and m = side slope of cross section. Page 6-18