Rigidity (psychology)

Abstract: In this paper the combinatorial properties of rigid plane skeletal structures are investigated. Those properties are found to be adequately described by a class of graphs.

Abstract: I work to unbundle the structure of inertia into two distinct categories: resource rigidity (failure to change resource investment patterns) and routine rigidity (failure to change organizational p...

Abstract: A GENERAL SOLUTION IS PRESENTED TO THE PROBLEM OF EXPANSION OF SPHERICAL AND CYLINDRICAL CAVITIES IN AN INFINITE SOIL MASS. THE SOIL IS ASSUMED TO BEHAVE AS AN IDEAL ELASTIC-PLASTIC SOLID, FOLLOWING THE COULOMB-MOHR FAILURE CRITERION AND EXHIBITING VOLUME CHANGES IN A PLASTIC REGION SURROUNDING THE CAVITY. BEYOND THE PLASTIC REGION THE SOIL IS ASSUMED TO BEHAVE AS AN ISOTROPIC, LINEARLY DEFORMABLE SOLID. IT IS SHOWN THAT THE PRINCIPAL PARAMETERS AFFECTING THE ULTIMATE CAVITY PRESSURE ARE: THE INITIAL GROUND STRESS, STRENGTH AND VOLUME CHANGE CHARACTERISTICS OF THE SOIL, AND AND THE RIGIDITY INDEX OF THE SOIL (DEFINED AS THE RATIO OF SHEAR MODULUS TO INITIAL SHEAR STRENGTH). NUMERICAL EXAMPLES SHOW THE USE OF THE DERVIED SOLUTIONS FOR COMPUTATION OF ULTIMATE CAVITY PRESSURE, EVALUATION OF PRESSUREMETER TESTS AND COMPUTATION OF POREWATER PRESSURE CAUSED BY PILE DRIVING. /ASCE/

Abstract: Abstract Suppose a finite configuration of labeled points p = (p1,. . . ,pn) in Ed is given along with certain pairs of those points determined by a graph G such that the coordinates of the points of p are generic, i.e., algebraically independent over the integers. If another corresponding configuration q = (q1,. . . ,qn) in Ed is given such that the corresponding edges of G for p and q have the same length, we provide a sufficient condition to ensure that p and q are congruent in Ed. This condition, together with recent results of Jackson and Jordán, give necessary and sufficient conditions for a graph being generically globally rigid in the plane.

Abstract: A method is presented for calculating the seismic response of a system of horizontal soil layers. The essential element of the method is a rheological model suggested by Iwan which takes account of the nonlinear hysteretic behavior of soils and has considerable flexibility for incorporating laboratory results on the dynamic behavior of soils. Finite rigidity is allowed in the underlying elastic medium, permitting energy to be radiated back into the underlying medium. Three alternate ways of integrating the equations of motion are compared, an implicit technique, an explicit technique, and integration along characteristics. An example is set up for comparing the different methods of integration and for comparing the nonlinear solution with a solution based on the widely used equivalent linear assumption. The example consists of a 200-m section of firm alluvium excited at its base by the N21E component of the Taft accelerogram multiplied by four to produce a peak acceleration of 0.7 g and a peak velocity of 67 cm/sec. The three techniques of integration give very similar results, but integration along characteristics has the advantage of avoiding spurious high-frequency oscillations in the acceleration time history at the surface. For the chosen example, which has a thick soil column and a strong input motion, the equivalent linear solution underestimates the intensity of surface motion for periods between 0.1 and 0.6 sec by factors exceeding two. The discrepancies, however, would probably be less for input motion of lower intensity. At longer periods the equivalent linear solution is in essential agreement with the nonlinear solution. For the same example both solutions show that, compared to a site with rock at the surface, motion at the surface of the soil is amplified for periods longer than 1.5 sec by as much as a factor of two. At shorter periods the amplitude is reduced.