【實用教育app】Auto Truss - Hand Calcs|最夯免費app-綠色工廠好玩App

Auto Truss - Hand Calcs automatically generates the hand calculations required to solve any statically determinate or indeterminate truss on a two dimensional plane. The generated report shows all the steps that are required to solve these problems by hand, with well formatted and neat calculations within a customisable report (Latex & HTML) that can be viewed on the phone or easily exported to another device or computer. This app is well suited for first and third year engineering students to learn statics and structural analysis, tutors and lectures to quickly provide fully worked solutions and practising civil, mechanical, aeronautical and structural engineers who would like an alternative method to check finite element results or provide hand calculations.

The methodology used to find the forces within the truss is statics when determinate and the virtual work principal when indeterminate. This approach lends itself well to hand calculations of trusses because they generally only have a few degrees of indeterminacy leading to smaller flexibility matrices for statically indeterminate trusses than what would be required from the finite element or direct stiffness methods which require a matrix row and column for every degree of freedom. Further to the calculations being less involved, the methodology is different from finite elements and therefore it is an ideal method for checking finite element results.

A data connection is required for the first report as the maths is formatted with Java script but all further reports will not require a data connection as the required data is saved to the phone during its first run. The report can be exported using Dropbox, Gmail and possibly other programs installed on the phone or tablet where it can be edited or printed. Additionally the Maths is formatted faster on a computer.

Planed future features:

Inclusion of units (currently consistent units must be used); and

Possibly changing the default report text to better meet the needs of users.

This program uses tabular data entry where the input requirements are as follows:

Node coordinates and member links are zero indexed;

Links can be formed by giving the index of the nodes which can be obtained from observing the free body diagram (FBD) behind the input;

There can be no gaps between the rows of nodes and links;

The FBD is updated after the data for a particular set such as the nodes, links, member properties, constraints and forces are entered and a new cell is pressed;

The member properties are applied as follows either the cross sectional area (A) and Young’s modulus (E) are given in one cell with a member group name to their left resulting in all members having the same sectional properties

all the different types of members properties are given once with a member group name to their left and the group name given next to the link that that sectional property applies to. Applying properties in this way makes it easier to identify which sectional property applies to which member and stops input repetition the same A and E values;

Restraints are entered by giving the node that is restrained followed by the reaction direction with 0 degrees being the resultant in the positive x direction and 90 degrees being the positive y direction; and

Forces are applied in the same manner as restraints but with the force magnitude given after the direction.

A Latex file is now generated each run and a PDF can be created with a separate compiling app. An internet connection is required on its first run only and lots of error messages will appear in the compiling app, ignore them and after quite some time the PDF will be ready.