DYNA6.1 Frequently Asked Questions

Yes, it can handle any number of machines on the same foundation, including the case of some being idle. Simply, the load from an operating machine represents its contribution to the response. If the machine is idle, motor/compressor combinations. Also, it can model a rectangular hole in the footing.

DYNA6 does vertical, lateral, rocking and torsional loads.

The DYNA6.1 program returns the response of rigid foundations to all types of dynamic loads. The rotation of centrifugal or reciprocating machines, shock-producing machines, earthquakes, traffic and other sources of dynamic forces can produce these loads. The foundation can be supporting a single or multiple machines. The response to harmonic loading for a flexible, rectangular mat on elastic half-space or on a group of piles can also be calculated. The stiffness and damping constants of the foundation (needed for the analysis) are evaluated within the program for surface foundations, embedded foundations and piles, pile interaction in a group and other features. For rigid footings, all six degrees of freedom are considered as coupled machines. Although you mentioned that your program can support single and multiple machines, does this mean that the program can analyze multiple machines working at the same time. If yes, what is the maximum number of machines it can model.

The foundation stiffness and damping constants (matrices) are also returned for possible use in soil-structure interaction analysis. These constants are available for rigid footings, flexible mats (caps) on piles, or piles without any connecting cap, and also for flexible mats on elastic half-space.

The DYNA6.1 program returns the response of rigid foundations to all types of dynamic loads. The rotation of centrifugal or reciprocating machines, shock-producing machines, earthquakes, traffic and other sources of dynamic forces can produce these loads. The foundation can be supporting a single or multiple machines. The response to harmonic loading for a flexible, rectangular mat on elastic half-space or on a group of piles can also be calculated. The stiffness and damping constants of the foundation (needed for the analysis) are evaluated within the program for surface foundations, embedded foundations and piles, pile interaction in a group and other features. For rigid footings, all six degrees of freedom are considered as coupled.

Yes, you are correct, DYNA6.1 is the right software for the job you describe. It can calculate the frequency dependent stiffness and damping constants of both shallow and pile foundations to different types of dynamic loads.

Yes.

No it does not. The effect of increased pore water pressures can be accounted for approximately by adjusting the shear modulus of the soil to reflect the corresponding degradation. It can model effect of liquefaction by reducing shear wave velocity of liquefied layer to expected level. It can model effect of liquefaction by reducing shear wave velocity of liquefied layer to expected level.

Based on Novak’s plane strain theory for single piles, and interaction factors effects considering Kaynia and Kausle (1982) and El Naggar and Novak (1995) for considering the stiffness and damping of the pile group.

Definitely yes.

The individual pile stiffness will differ depending on its position within the group. However, the group stiffness already accounts for the interaction between the piles, which depends on the configuration of the pile group. When we divide the group stiffness by the number of piles, we get the average stiffness per pile. This is sufficiently accurate for the purpose of getting the dynamic response of the machine-foundation system (global behaviour).

The main advantage of DYNA6.1 is its ability to calculate the frequency dependent stiffness and damping constants of both shallow (footing) and deep (pile) foundations. These stiffness and damping constants can then be used to represent the foundation flexibility in your finite element modeling to obtain the response. For the case where the foundation can be considered to behave as a rigid body, the program can also calculate the dynamic response to different types of dynamic loads (harmonic, transient, impact or random). The program DYNA6.1 complements the FE design tool you have. As a matter of fact, it offers an essential component of the design. As you probably know, the stiffness and damping constant of a foundation system subjected to dynamic loading (which is the case for foundations supporting turbines and generators) are a function of the frequency of the loading, which is in turn a function of the operating speed of the equipment. This is particularly crucial for deep foundations, and for shallow foundations resting on layered soil or homogeneous soil with Poisson's ratio approaching 0.5. In any of these cases, successful design requires the evaluation of the stiffness and damping constants representing the soil (what you describe as simple springs) must be calculated with due consideration of the loading frequency. Only DYNA6.1, not the FE model, can calculate these stiffness and damping constants. To summarize, The program DYNA6.1 can be used to calculate stiffness and damping constants, as well as the response of all types of foundations (assuming rigid body models) to different types of dynamic loads. It can also calculate stiffness and damping constants that can be later in an FE model to represent the soil (soil or pile springs).

Yes, it can handle all the tasks you describe.

Yes, it does handle pile supported machinery foundations.

DYNA6.1 will show at least 6 modes (i.e. 6 natural frequencies) associated with the rigid body movements. This means you will have a natural frequency along the vertical and 2 horizontal directions as well as torsional and 2 rocking directions. After you run DYNA6.1, you can plot the responses vs. frequency at the C.G. of the machine-foundation system. These responses will display peaks. The location of the peak identifies the natural frequency

DYNA6.1 can solve the problem you cited. It is very widely used in the industry for similar projects.

Yes, but assumes rigid body movement, which is justified for many cases depending on the dimensions of the tabletop. If you want to consider flexibility of tabletop, the program provides frequency dependent stiffness and damping constants that can be used in FE to obtain the response to the dynamic loads. In this case, DYNA6.1 can be used in the preliminary design until a foundation configuration is selected, then FE can be used to verify its suitability.

Yes, DYNA6.1 provides frequency dependent stiffness and damping constants and accounts for the interaction between the piles (steel or concrete) and soil considering the group effect. It also accounts for the interaction of the pile cap with the adjacent soil if there is an embedded pile cap.