Dynamic load response

Dynamic load response time This is the amount of time it requires the power supply to recover to within load regulation limits in response to a step change in the load. 

Dynamic Load Response of Plastics Members and Effects of Cyclical Loading... 

Reset, then, is necessary if offset is to be eliminated altogether. Whether proportional and derivative are useful modes depends on the nature of the process. If rapid load changes outside the forward loop may be encountered, proportional and derivative action could be advantageous. If the process Is fundamentally non-self-regulating, as in level control, proportional action Is essential. Finally, if the process is fairly easy to control because of the absence of dead time, derivative may be useful in Improving the dynamic load response-but this is unusual. 

Jones, O.E. (1972), Metal Response under Dynamic Loading, in Behavior and Utilization of Explosives in Engineering Design (edited by Henderson R.L.), University of New Mexico Press, Albuquerque, pp. 125-148. 

D.E. Mikkola and R.N. Wright, Dislocation Generation and its Relation to the Dynamic Plastic Response of Shock Loaded Metals, in Shock Waves in Condensed Matter—1983 (edited by J.R. Asay, R.A. Graham, and G.K. Straub), Elsevier Science, New York, 1984, 415 pp. 

An adequate description of material behavior is basic to all designing applications. Fortunately, many problems may be treated entirely within the framework of plastic s elastic material response. While even these problems may become quite complex because of geometrical and loading conditions, the linearity, reversibility, and rate independence generally applicable to elastic material description certainly eases the task of the analyst for static and dynamic loads that include conditions such as creep, fatigue, and impact. 

Response of a material under static or dynamic load is governed by the stress-strain relationship. A typical stress-strain diagram for concrete is shown in Figure 5.3. As the fibers of a material are deformed, stress in the material is changed in accordance with its stress-strain diagram. In the elastic region, stress increases linearly with increasing strain for most steels. This relation is quantified by the modulus of elasticity of the material. 

Ultimate strength for concrete is greater under dynamic loads. Though the modulus of elasticity is also greater, this difference is small and is usually ignored. Figure 5.6 describes the relationship between dynamic and static response for... 

Quality of joist welds is also critical to achieving a ductile response. Welding is performed to Steel Joist Institute standards and the lack of specific criteria may prevent development of a predictable ultimate capacity. Special precautions must be taken to remedy this problem such as requiring manufacture in accordance with AWS criteria. Open web steel joists are intended for relatively low static loads and thus are suitable only for low dynamic loads as well. 

Most blast door manufacturers opt to perform static load tests on prototype assemblies of low-range blast doors to demonstrate that the assembly will resist the blast overpressure specified. Static tests should be accepted only if the dynamic structural response and dynamic load factors have been considered and the door, frame, and restraining hardware are manufactured using the same materials, dimensions, and tolerances as those in the prototype static test. 

The variability of the process parameters with flow causes variability in load response, as shown in Fig. 8-50. The PID controller was tuned for optimum (minimum-IAE) load response at 50 percent flow. Each curve represents the response of exit temperature to a 10 percent step in liquid flow, culminating at the stated flow. The 60 percent curve is overdamped and the 40 percent curve is underdamped. The differences in gain are reflected in the amplitude of the deviation, and the differences in dynamics are reflected in the period of oscillation. 

Dynamic loads of fast transient pressures are imposed in the presence of inhomo-geneously distributed combustion energy and are specific to the structure geometry. The response to an incident shock wave could be a movement of solid objects [60]. 

Commercial DMA instruments vary in their design. One commercial instrument is shown in Fig. 16.36, set up for a three-point bend test under dynamic load. A different commercial instrument schematic. Fig. 16.37 shows a sample clamped between two arms that are free to move about the pivot points [Fig. 16.37(a)] the electromagnetic drive and arm/ sample assembly are shown in Fig. 16.37(b). The electromagnetic motor oscillates the arm/sample system and drives the arm/sample system to a preselected amplitude (strain). The sample undergoes a flexural deformation as seen in Fig. 16.37(a). An LVDT on the driver arm measures the sample s response to the applied stress, calculates the modulus (stiffness) and the damping properties (energy dissipation) of the material. 

Malcolm, L.L. An Experimental Investigation of the Frictional and Deformational Responses of Articular Cartilage Interfaces to Static and Dynamic Loading, Ph.D. thesis. University of California, San Diego, 1976. 

---