Why is the element stiffness matrix singular in a finite element formulation? 1. So that it can accomodate rigid element dis- placements without introducing spurious nodal 2 Because we made a mistake in the formula- tion the stiffness matrix should not be sin- g 3. Because we havent enforced any displace ment boundary conditions(it's a variational approach after all) Statement(1)
We are going to consider the forces exerted on a material. These can be external or internal. External forces come in two flavors: body forces(given per unit mass or volume) and surface forces(given per unit area). If we cut a body of material in equilibrium under a set of external forces along a plane as shown in fig. 1. and consider one side of it we draw two conclusions: 1 the equilibrium provided by the loads from the side taken out is provided by a set of forces that are distributed among the material particles adjacent to
PARTO- PRELUDE: REVIEW OF UNIFIED ENGINEERING THERMODYNAMICS [AW pp 2-22, 32-41(see IAW for detailed SB&vw references): VN Chapter 1] 0.1 What it's all about The focus of thermodynamics in 16.050 is on the production of work, often in the form of kinetic energy(for example in the exhaust of a jet engine)or shaft power
