Search results for "Relative motion"
showing 4 items of 4 documents
Rendezvous Guidance Trajectories via Multiple-Subarc Sequential Gradient-Restoration Algorithm
2009
We consider the three-dimensional rendezvous between a target spacecraft in a circular orbit and a chaser spacecraft with an initial separation distance and an initial separation velocity. We assume that the chaser spacecraft has variable mass and that its trajectory is governed by three controls, one determining the thrust magnitude and two determining the thrust direction. We employ the Clohessy–Wiltshire equations, describing the relative motion of the chaser vis-a-vis the target, and the multiple-subarc sequential gradient-restoration algorithm to produce first optimal trajectories and then guidance trajectories for the following problems: P1—minimum time, fuel free; P2—minimum fuel, ti…
Optimal Starting Conditions for the Rendezvous Maneuver, Part 2: Mathematical Programming Approach
2008
In a companion paper (Part 1, J. Optim. Theory Appl. 137(3), [2008]), we determined the optimal starting conditions for the rendezvous maneuver using an optimal control approach. In this paper, we study the same problem with a mathematical programming approach.
Non-local stiffness and damping models for shear-deformable beams
2013
This paper presents the dynamics of a non-local Timoshenko beam. The key assumption involves modeling non-local effects as long-range volume forces and moments mutually exerted by non-adjacent beam segments, that contribute to the equilibrium of any beam segment along with the classical local stress resultants. Elastic and viscous long-range volume forces/moments are endowed in the model. They are built as linearly depending on the product of the volumes of the interacting beam segments and on generalized measures of their relative motion, based on the pure deformation modes of the beam. Attenuation functions governing the space decay of the non-local effects are introduced. Numerical resul…
Ein modell zur beschreibung bimolekularer reaktionen zwischen reaktiven gruppen, die in zwei polymerknäuel eingebaut sind
1968
Die Beobachtung, das die Geschwindigkeitskonstante des Kettenabbruchs bel der radikalischen Polymerisation des Methylmethacrylats umgekehrt proportional der Viskositat des Losungsmittels und vollig unabhangig vom Molekulargewicht ist, wird durch folgendes Modell erklart: 1. Die Polymerknauel behindern nicht ihre gegenseitigen Bewegungen und konnen sich bei einer Begegnung vollstandig durchdringen (Unabhangigkeit der Selbstdiffusionskonstante von der Konzentration). 2. Die Reaktion findet im Uberlappungsraum zweier sich begegnender Polymerradikale wahrend der Begegnungsdauer τ statt. Eine statistische Rechnung zeigt, das unter dieser Annahme die gemessene bimolekulare Geschwindigkeitskonstan…