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Fig. 3.4. Equations using units.

Fig. 3.4. Equations using units.

To obtain the answer, the units for /u k must be N/mm2 and d must be in mm. The equation is then set up with the dimensions removed from each function, and at the end of the equation, type *N*mm. To obtain the solution, type My Rk = and the answer will be given in N mm units as shown in the following example:

N mm

In the examples in the book, there are some Mathcad functions that are commonly used and an explanation of how two of these functions are set up for use in calculations is given.

3.3.5.1 Maximum and minimum values

The Mathcad function will determine the maximum or minimum value where a function in a problem has more than one value.

Example. The effective number of bolts in a row loaded parallel to the grain will be the minimum of value n (the number of bolts in the row) and function n0'9^a1/(13d) (where a1 is the bolt spacing along the row and d is the bolt diameter). When these functions have been defined within the calculation the minimum value, say nef.r, will be obtained by typing n.e/r:mm(n,nA0.9shift*(a.1/13*d)A0.25). The reference to 'shift' in the expression means to press the spacebar key. To obtain the answer on a new line press return [J] and type n.e/.r=.

For example, where the number of bolts (n) in a row in a connection equals 3, each bolt diameter (d) is 12 mm, the bolt spacing parallel to the grain (a1) is 90 mm, and the connection is loaded parallel to the grain, the effective number of bolts in the row, nef, will be nef := min nef = 2.34

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