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Let COSMOSWorks simplify your next up-front drop test

In the past, you had two choices for running an up-front drop test: drop-and-watch or simulate on a computer with complex nonlinear FEA software. Now, COSMOSWorks® software provides an up-front drop test that lets you depict the impact of a model in just three easy steps:


Step 1: Define the study and choose the materials
Open your model in SolidWorks® software. (Check COSMOSWorks in the Add-In list, so it appears on the SolidWorks menu bar.) Open a Study dialog box in COSMOSWorks, type in a name for the study, and select Drop Test under Analysis type.

COSMOSWorks 2005 includes a series of easy-to-use dialog boxes that simplify the simulation of the drop test. For example, you can select Drop Test in the Study dialog box to launch your analysis.

If you already added material properties to your SolidWorks model, they will show up automatically in the COSMOSWorks Manager Tree. Once the analysis is set up, you can also add or change material properties in COSMOSWorks.

Step 2: Specify the drop height and floor orientation
With Drop Test Setup Property Manager, you can define your study using drop height (h) or velocity at impact (v). (Determine the velocity at impact with COSMOSMotion™ beforehand.) If you enter a drop height, the program automatically calculates the velocity using the formula v= (2gh)1/2, where g is gravity and h is height.

The Drop Test Setup box allows you to use the drop height or the velocity at impact. The Result Option box lets you specify an adequate time solution for your study.

Next, enter the gravity acceleration and the impact plane orientation. Target Orientation defaults to normal to gravity, but can be changed to make it parallel to a reference plane. A friction coefficient between the body and floor can be entered to account for floor material.

Step 3: Run the analysis and get the study results
The Results Option dialog box lets you specify the number of equally spaced instants when the results are saved for all nodes and refine the graphs at selected vertices and reference points. Plus, you can specify the instant when results are stored and save on disk space.

You can adjust the time after impact when COSMOSWorks records the results. In this toy plane model, the time is saved as 5,000 microseconds. As a toy plane hits the ground nose first, the shock wave travels up the plane and out through the wings to the tail.

Since the impact period is brief, COSMOSWorks calculates in microseconds. When an object hits the floor, a shock wave travels from the impact point to the farthest boundary and back again. If you specify an adequate time solution, the study can evaluate secondary impacts, too.

Drop test studies generate extensive information due to the small time increments in which the solver calculates the response. If you perform a first pass using default settings to obtain the initial results, you may cut even more time from analysis runs. Later, you can choose the variables that you want to refine.

After running the analysis, COSMOSWorks presents the results in colorful contour plots of stress, displacement, and strains at the instants that the program stored the results at all locations. You can save contour plots as JPEG, BMP, HTML, and VRML, or include them in eDrawingsTM.

Facts to remember
• COSMOSWorks makes it easy to compare a dropped object’s impact from different orientations, which is useful in designing products like mobile phones and hazardous waste containers.
• COSMOSWorks drop test simulations support plasticity in determining permanent deformations, such as dents after impact.
• COSMOSWorks does not currently support interactions between assembly components after impact or of two objects colliding. It also assumes that the impact surface is unyielding, whereas real-world surfaces give to absorb some of the shock.