Unit Load Method Research Articles

Analysis of aircraft structures: an introduction

Introduction to the second edition Introduction to the first edition Part I. The Fundamentals of Structural Analysis: 1. Stress in structures 2. Stresses and coordinate axis rotations 3. Displacements and strains 4. Strains in rotated coordinate systems 5. The mechanical behavior of engineering materials 6. Linearly elastic materials Part II. Introduction to the Theory of Elasticity: 7. The theory of elasticity 8. Plane stress theory of elasticity solutions Part I and Part II review questions Part III. The Engineering Theory for Straight, Long Beams: 9. Bending and extensional stresses in beams 10. Beam bending and extensional deflections 11. Additional beam bending topics 12. Uniform torsion of beams 13. Beam torsion approximate solutions Beam bending and torsion review questions 14. Beam shearing stresses due to shearing forces Part IV. Work and Energy Principles: 15. Work and potential energy principles Part V. Energy Based Numerical Solutions: 16. Precursor numerical analyses 17. Introduction to the finite element method 18. Finite element truss problems 19. Basic aspects of multidimensional finite elements 20. The unit load method for determinate structures 21. The unit load method for indeterminate structures Parts IV and V review Part VI. Extensions to Plate Theory and Finite Element Applications: 22. Thin plate theory 23. Elastic and aeroelastic instabilities Selected answers to Part I exercises Selected answers to Part II exercises Selected answers to Part III exercises Selected answers to Part IV and Part V exercises Selected answers to Part VI exercises References.

Multiple product inventory policies with unit load and storage space considerations

In this paper the appropriate unit load for each product in a multi-product inventory system is determined and used to calculate the best policy given limited storage space. An inventory system with constant demand and replenishments rates is considered. The Economic Unit Load (EUL) method is revised to include multiple container types and the Equal Order Interval (EOI) method is extended to consider unit loads and finite replenishment rates. The methods are compared using total cost and average space utilization as the criteria.

On geometrically nonlinear contact problems with friction

The analysis of quasi-static contact problems applying an ‘updated’ respectively a ‘total Lagrangian’ formulation is extended in a way that frictional effects according to Coulomb's law are being incorporated into the incremental procedure which is closely related to the unit load method. Further novel aspects are to be found in the iterative computation of the tangential components of the stress distribution in the contact area due to various boundary conditions. The second part of the paper deals with the application of the nonlinear programming technique to problems with unilateral constraints. Using standard finite element techniques an ‘augmented Lagrangian’ is defined for a predeformed compressed rod. Neglecting frictional effects, the contact zones and the nodal contact forces between the deformed rod and lateral rigid objects are described by the Kuhn-Tucker conditions.

Unit Load Method for Deflections of Planar, Nonlinear Structures

The unit load method, which is also known as a virtual work method, as well as by several other names, is a widely used tool for calculating deflections of linear structures. A procedure is developed here, which consists of similar steps and can be used when nonlinear material is involved. The formulae are developed based on the concept of complementary energy and the Castigliano theorem extended to nonlinear systems. A few simple examples are solved using this method and the results are compared with those obtained by a finite-element program. It appears that a blend of both types of analysis may be the optimal tool in many situations.