December 5, 2016

Cost saving by reducing mass of the diesel generator frame

Industry: Industrial Equipment | Product: pSeven | Company: STM R&D Center

Objective

Diesel generators developed for JSC STM Research and Development Center are intended for the use as power units in locomotive engineering. The company faces the challenge of reliability and fuel efficiency increase and torque properties improvement of power units. One of diesel generator optimization stages is the minimization of its frame`s mass, which ensures essential material economy in large-scale production.

Challenges

The following input data was provided to DATADVANCE: assembly model, drawings, diesel generator mass, the center of mass disposition, material type. Problem solution steps are to define input and output parameters, automate calculations and perform design mass optimization. Besides, customer requirements to the new design included:

• Design durability and stiffness within three loading conditions shall correspond to the maximum operational loadings;
• The areas of frame fastening to the mating parts and fastening holes should not be changed.

Solution

The solution included several stages. First, the approximation and parameterization of initial frame geometry were performed. During the approximation, small structural parts were removed as insignificant for the stress-strain behavior of the design in order to create simplified simulation models by the finite elements method. 37 geometry parameters were selected for variation out of 56 parameters fully describing the frame geometry.

Then the FEM model creation in the CAE system, three loading conditions and calculation of results were automated. Along with the constraints applied by the customer, another geometry constraints were added to avoid geometry degeneration or overlapping. Design mass was set as the optimization criterion.

The global optimization method was applied to find the optimal decision, implemented in pSeven. The method is based on the surrogate-based optimization (SBO) - the unique technology developed by DATADVANCE. The advantage of this approach is the possibility to find the global minimum of function – in other words, the optimal parameters of a product - with much less time-consuming calculations.

Benefit

Thanks to the built-in integration with CAD/CAE packages and to the unique optimization algorithms pSeven allowed to quickly build the optimization workflow and to solve the task. The optimal configuration of the diesel generator frame which fits conditions and requirements set by the customer was found in less than 150 calculations. Just to compare, the solution of a similar multiparametric task with the use of the classic gradient methods of optimization would require 10 times more calls to the external solver.

As a result, the mass of the diesel generator frame reduced from 1416 kg to 1234 kg without sacrificing the durability and other characteristics of a product. This is 12% lighter than the initial configuration.