If you have already meshed a part, a part instance, or a region, ABAQUS/CAE allows you to change the element order without having to recreate the entire mesh. If you change between linear and quadratic elements, ABAQUS/CAE simply adds or removes the midside nodes as required.
Warning: If you change the order of the elements in adjacent regions of a part or part instance, ABAQUS/CAE cannot create tied contact between the linear nodes and the quadratic nodes at the boundary of the two regions. You must create two separate part instances and create tied contact between them.
If the part or part instance is an orphan mesh, you can change the order of all the elements or you can change the order of only selected elements. An orphan mesh contains no underlying geometry information, and as a result you should take care when changing the order of the elements. If you change the elements in an orphan mesh from quadratic to linear, all information on the location of the midside nodes is lost. As a result, if you subsequently decide to change back from linear to quadratic elements, you will not be able to return to the original mesh. For more information, see “What kinds of files can be imported and exported from ABAQUS/CAE?,” Section 10.1.1.