Access to Expert Knowledge

If the people of Pisa had access to Alex Tomanovich’s footing analysis calculation do you think they would have built that famous ‘leaning’ tower? When you download calculations from the ExcelCalcs repository of solved problems you access a live document encompassing years of knowledge and best practise. Our documents are prepared by working engineers not focused on the academic pursuit of theory but on practical solutions to solve common engineering problems. Best still you’ll always find a ‘Forum Link’ so you can ask the calculation author any question if there is something in it you cannot understand. The ExcelCalcs repository saves you time, taps into expert knowledge and helps you avoid making mistakes.

We recognise that preparing a repository calculation takes a good deal of knowledge of the subject matter and a good deal of effort in laying out the calculation in a readily useable form. So if you have a spreadsheet to share with us we’ll be delighted to share all ours with you. If you don’t have a calculation to share then just $90 per year gives you full access to our repository calculations and a commercial license for XLC our essential engineering addin for Excel. Take a look at the Repository News section below which features new calculations uploaded since our last newsletter, you’ll find something for civil engineers, structural engineers and mechanical engineers.

This year we intend to increase the user base by a factor of 10 so we appreciate all efforts to spread the word about ExcelCalcs. Thank you for forwarding emails to colleagues, adding links to us on your websites and blogs.

Repository News

SCF circular shaft with keyseat.xlsx

A stress concentration is the phenomenon for which stress in a body becomes much more than the nominal stress due to abrupt change in cross section or presence of discontinuities. 'Stress concentration' (often called stress raisers or stress risers) is a location in an object where stress is concentrated. Fatigue cracks always start at stress raisers, so removing such defects increases the fatigue strength. This calculation was used in our consultancy work when we were asked to consider the fatigue implications of adding a keyslot feature in the ends of an actuator arm on a tilting train. Our consultancy work also undertook a finite element analysis of the stress raiser and the calculation was used to validate the results.

BUOYANCY ANALYSIS FOR CONCRETE PIT OR TANK

"BUOYANCY.xls" is a spreadsheet program written in MS-Excel by Alex Tomanovich for the purpose of performing a buoyancy analysis, checking the resistance to flotation, for either an open or buried/enclosed rectangular concrete pit or tank. This program is based on the Archimedes Principal on buoyancy which is stated as follows: "Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object". Thus, the volume of water displaced by the object multiplied times the unit weight of water is equal to the buoyant force.

Light-weight Composite Beam Design

Consider a cantilever beam with a load applied at the free end. The applied load creates a bending moment which is a maximum at the fixed end, and a shear force along the length of the beam. In a sandwich panel these forces create tension in the upper skin and compression in the lower skin. The core spaces the facing skins and transfers shear between them to make the composite panel work as a homogeneous structure. The following beam loading conditions can be selected using a drop down combo box.
L1) Simple Support with Uniform Load Distribution
L2) Both Ends Fixed with Uniform Load Distribution
L3) Simple Support with Central Load
L4) Both Ends Fixed with Central Load
L5) Cantilever with Uniform Load Distribution
L6) Cantilever with Load at End
L7) Cantilever with Triangular Load Distribution
The panel is checked against critical intra-cell buckling, critical face wrinkling stress, allowable tensile stress on face, core shear stress and deflection.

Composite Panel Calculations.xlsx

A similar calculation considers a composite panel simply supported on four edges subject to a uniformly distributed load. It makes the same checks as the beam calculation but because plate theory is a bit more involved than beam theory it uses a number of charts to determine multipliers and coefficients for the calculation. Following methods described on this site to automatically read lookup tables performing this calculation is just as quick as the beam calculation spreadsheet. This calculation was recently used in our consultancy work when we were asked to about a light weight floor solution for an urban tramway floor.

RECTANGULAR SPREAD FOOTING ANALYSIS

"FOOTINGS.xls" is a spreadsheet program written in MS-Excel by Alex Tomanovich for the purpose of analysis of rigid rectangular spread footings with up to 8 total piers, and for either uniaxial or biaxial resultant eccentricities. Overturning sliding, and uplift stability checks are made when applicable, and resulting gross soil bearing pressures at the four (4) corners of the footing are calculated. The maximum net soil bearing pressure is also determined.