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Asalamualaikum, how to do non linear analysis? can i do non linear analysis manually? Example: If i have to study non linear analysis, i have made a cantilever beam with point load at its end. for non linear analysis, i have used Tresca model for material non linearity and run it as non linear analysis option. 1. where can i find the values to put in Tresca model? 2. What does it mean if result converges or divergence occured? 3. How can I verify my result since i don't know any manual calculations or dont have any example? Thankyou

Walaikum Salam To perform Non Linear Analysis manually is very difficult. May be you can not find the solution for this. First of all, what do you mean by non linear on a cantilever beam? you can add non linearity in cantilever beam but then how you will apply seismic loading (static or dynamic) on this cantilever beam. Actually, this type of analysis is (in my opinion) is feasible for global level not for member local level. You can choose a structure and add material non linearity and then apply static or dynamic loading and then check the results. I am not sure which values you need for Tresca model. It depends upon your software which values it needs. Secondly, IT IS ALMOST IMPOSSIBLE TO VERIFY THE RESULTS OF NON LINEAR AT ALL. This needs practical judgement to check the results but can not be verified by any means. Thanks Muneeb

What is the difference between Linear and Non Linear Analysis..............What are the advantages of Non Linear Analysis.........Why do we need Non Linear Analysis........Can anybody explain????

Well explained by Mr, Waseem. The first type of Non-Linearity, the Geometric Non-Linearity can easily be incorporated into the structural model. Adding Material Non-linearity is quite difficult. Even there is no code which provides this method. There are many guidelines which normally Structural Engineers follow to add these geometric non linearity. The parameters given in the code are basically derived by considering these non linearities but these parameters do not give 100 percent reliable results, because everything depends upon the shape of structure. The code mostly covers the buildings which has symmetric shape. For example in case of Wind if the structure is not symmetrical or rectangular in shape we can not use the code based factors with 100 percent reliability. Thanks Muneeb

In Linear analysis, forces and deformations are directly proportional to each other. For example axially loaded bar has extension equal to PL/AE...more P so more extension. This is linear analysis (inclined line in graph between P and delta). In non-linear analysis forces and deformations are not directly proportional. For example, even after removing load, strain continues to increase. There are three types of non-linearaties; 1. Geometric; for example p-delta (second order effects) structural stiffness can change as the structure deforms, and therefore the displacement will not be proportional to the applied load 2. Material; for example stress is not directly proportional to strain anymore after Hook's Law limit 3. Boundary conditions; contact between components depends on the load between the components, which in turn affects the stiffness of the contacting parts, and therefore produces a displacement response that is not proportional to the applied load. These 3 types of non-linear behavior can be studied in either A. Static domain or B. Dynamic domain One need to perform non-linear analysis if either of the above problem needs to be analysed and for those structures where one of the above 3 problems post sufficient doubt in linear analysis range.