$90 For Your Calculation.

Help ExcelCalcs develop its content and we’ll reward you with free XLC Pro credits worth up to $90. So if you have been intending to pick up XLC skills to prepare professional quality calculations please take this opportunity to learn and earn. Existing XLC Pro subscriptions will be extended and even commercial users on an XLC Ed subscription can find redemption in submitting content. Our Administrators co-ordinate site contributions through the forum:

Administrator's Request - Motion

Administrator's Request - Trajectories

Administrator's Request - Relative Velocity

Administrator's Request - Any HyperPhysics Content

Please feel free to send this to friends and colleagues too, the more contributions the better. 

ExcelCalcs Supports QuickStart

Dr Martin Fisher and Nick Moon are the founders of a non-profit social enterprise called KickStart which uses technology and market promotion as key drivers. It is dedicated to the proposition that innovative equipment and systems can transform the lives of low-income African entrepreneurs by enabling their entry into much more profitable businesses. The idea was to design technology that was within the financial reach of Africa's poor,  and could return the initial investment in three to six months. They designed a machine to make building blocks, a press to make cooking oil out of sunflower seeds, and a hay baler. But their biggest success was with subsistence farmers, in irrigation: a small pressure pump called the MoneyMaker that would allow them to irrigate their land so they could start growing cash crops.

Dr Fisher has won numerous awards and recognition for his inventions and work as a social entrepreneur, including the IDEA Design Gold Medal, TIME Magazine's 2003 European Hero award, 2005 Skoll Award for Social Entrepreneurship, and the Schwab Foundation's "2003 Social Entrepreneur of the Year" award. In 2008 he was named Engineer of the Year by Design News magazine. Also in 2008, he received the prestigious $100,000 Lemelson-MIT Award for Sustainability" for his achievements in transforming the lives of hundreds of thousands of poor Africans though invention and innovation.

We are pleased to be supporting their worthy cause. Alan Spybey is KickStarts Director of Technology who explains how ExcelCalcs is used throughout the design process...

"The way I see ExcelCalcs helping us looks like this:

• Initial calculations. Maths modelling is essential for rapid first shots at section sizes and other modelling, since FEA is finicky to set up and takes quite a while to run through a single configuration of a part or subassembly. Converting engineering equations to the single line format required in Excel is prone to error. Normally all one can see is a number as an output. A bracket in the wrong place can give a completely fallacious output. When one doesn’t construct the equation oneself, spotting an error is difficult since reviewing all the cell details in Excel for a team of engineers would take so much time that it would challenge the worth of having a team. Having ExcelCalcs check both allows the engineer to check his or her own work, and a supervisor to check the calculation structure more rapidly.
• Check against practical and FEA tests. Whilst the graphical output of FEA is impressive and convincing; can give insights on a subtle level in complex structures; and can show up hotspots of high stress; it is possible for two designers to come up with radically different results due to differences in the initial conditions set for meshing and stabilisation of the model. It is more rigorous to challenge the FEA output with numerical analysis based on standard engineering formulae, to see if the results are at least in the same ballpark. However, backing up FEA with paper calculations can be time-consuming, especially if a range of minor changes in inputs needs to be tested. I prefer to setup standard situations with engineering equations in a spreadsheet. The problems tend to arise from the initial conditions and fixture points assumed; and a check based on gut assumptions, simplifications, and spreadsheet checks can be very reassuring. It is then important to verify the right equations are being used and have no errors for which ExcelCalcs is a unique tool.
• Communication during development. The practice of FEA analysis being backed up by good old-fashioned maths is strongly supported by Martin, our CEO, who is partial to reviewing equations that he can dissect rather than graphical output with less transparent input and solving processes. ExcelCalcs permits a good compromise between electronic and paper computation – I can use spreadsheets for fast calculation, but the output can be displayed in a way comparable to pen and paper analyses, rather than the often illegible Excel formula format. This kind of presentation is important for co-reflectors both inside and outside the organisation"
• Final documentation. For posterity, and for a launch pad for redesigns, a summary set of documents for an approved design needs authoring. This needs to contain key maths calcs in the context of the equations being used so that future engineers know where they are starting from, and which key assumptions can be challenged, modified, or chucked out. The document needs to address a range of future basic queries from interested persons not actually involved in the design of the pumps. Clarity of the maths is a key feature of this kind of documentation."

ExcelCalcs Angel?... or Devil?

XLC Angels always rate their downloads and if they are commercial users they obtain an XLC Pro subscription. XLC Pro subscriptions can be purchased, earned by contributing a calculation, awarded to clients who use our engineering consultancy services or they can be given to attendees of our training courses.

Repository News

Topic	Author
POLEFDN.xls - A "glitch" was discovered in the "Pole Fdn (Czerniak)" worksheet of the "POLEFDN.xls" workbook. I was using a simple iterative approach to solve the polynomial equation for the theoretical embedment depth, "L". In Column V of the worksheet, I have what I term index numbers for each iterative evaluation of the expression to help isolate where the solution converges to zero. Problem was, I had an inadvertent small gap of numbers in the index numbers, and thus they were not completely sequential. One "lucky" gentleman had a design situation where his solution fell at that exact point where the gap in the index numbers occurred, and the solution crashed. Lucky for me he stumbled upon the problem. This has now been corrected and this workbook is now version 2.0.	ATomanovich
Dayton_Shear_Reinforcement_System_For_Square_Columns.xls - Updated to include ICC recognition per ESR-2696. Also the calculations now use a more precise burn-off length, and reflect a change in the plate thickness used with the 3/8" diameter studs.	MajorMagee
Dayton_Shear_Reinforcement_System_For_Round_Columns.xls - Updated to include ICC recognition per ESR-2696. Also the calculations now use a more precise burn-off length, and reflect a change in the plate thickness used with the 3/8" diameter studs.	MajorMagee
Linear Algebra [Page: 1,2] - Used to rank competitors from the strongest to the weakest within a competion group using the following scheme: all competitors will compete against each other in such a way that each one is pitted against each other the others exactly once.	SlideRule
DJ1 DJ2 UNB UNT UNL Ver 1.xls - This is short program for STAAD users. This will add DJ1-DJ2-LY-LZ at the end of STAAD file. Then you just have to copy this below parameter and check graphically. With this you can save a hell of time which you are spending for giving these parameters.The calculation is updated to version 1.5	ajayssarode