Table of Contents
Introduction of topic
A study of existing literature
Original: This article presents a review of existing literature in the field.
Paraphrased: This paper looks at the current literature in the subject area.
Validation of the Conclusion
Introduction
The console acts as a bridge for interaction between man and machine. The Console assembly is made up of HMIs (Human Machine Interfaces) and the Console shell. The console shell is where the HMI component gets mounted. HMI is an acronym for Human Machine Interface. It includes all electronic components such as LEDs, buttons, PCBs, etc.
As the console contains many electronic components, it is important to consider the safety of users when designing a product. Each console must be tested by UL before it can be put on the market.
Ball impact is one of several safety tests conducted on the console. The ball was a basketball, filled up to 1/3rd its volume with sand. This ball then hit the console. The impact test is similar but with one important difference.
A console may be damaged if it is hit by a ball for some unknown reason. The console can be damaged by the full impact. The main concern is gaining access to live wires after damage.
This paper aimed to link simulation and experimentation. Simulating a product during new product development is the only means to determine if it will pass UL standards safety tests. To understand the accuracy, you must compare the results of the accelerometer experiment with those of the simulation.
Literature ReviewS. Sridhar & SushilkumarVishwakarma studied the impact of sand on concrete walls using DEM to better predict the outcome. They wanted to develop a simulation that could capture the behaviours of sand-filled balls when they were impacted. The simulations showed close agreement with the experimental results. Hamidreza mahmoudi developed a finite component model of the pedestrian kinematics by using LS Dyna. Comparing the simulation with the experiment, we used the maximum acceleration and impact time. Edwin Fasanella & Karen Jackson described the best practices to model aircraft impact using explicit finite elements codes that are nonlinear and dynamic. In crash-analysis, the greatest concern is magnitude and duration. Discussions on digital filtering, experimental data analyses and other topics are included [4]. SMP Svensk’s report on impact testing methods using the swing element and accelerometers is compared to results in g. Frank, Stefan and Marika developed material models to simulate polymers in crash loads. The material models were applied on shell element in LS Dyna.
The pumpkin impact test setup used a ball of sand filled to about 3/4ths its volume, with the hook attached on top. The vertical height measured from the hinge-point is 39.2″. A few counter weights are kept behind the pumpkin-ball setup in order to prevent misbalancing during the ball’s motion. The Pumpkin Ball was adjusted in height and placement so that it struck the knob at its centre. The ball weighs approximately 10.5kg. Two triaxial acceleration sensors were used to determine the acceleration of both the pumpkin and the console.
Two accelerometers have been used in the tests. The first accelerometer was attached 76mm back from the impact area and the second was placed directly behind the ball. The maximum impact happens along the normal z-direction. The horizontal distances were 5″, 10″, and 15″.
The simulation has been performed using LS- Dyna, hypermesh and discrete particles to represent sand in the ball.
Four point one assumptions are made.
Modeling of screw connections using rigid and beam elements.
Modeled plastic parts (consoles) using tetrahedron element
Shell elements are used to model the sheet metal (top panel).
Simulation is done with a 500mm pumpkin ball
Material properties are assigned to ambient 23C temperature condition. Simulation does not include temperature effects
4.2 Loading condition and boundary condition
The ball is given the same energy by applying the Initial Velocity Z-Direction.
The model is subjected to a 1G force in the Y direction.
The top panel’s bottom surface is constrained to all DOF.
Rubber ball is modeled with shell elements and dry sand particles using discrete-element method (DEM).
Post processing is done using the LS- Prepost program. The material is allowed to withstand maximum stresses during each load case.
Validation and conclusionSince correlation was performed by comparing the acceleration values of simulation and experimentation, both were compared. In experimentation, the maximum acceleration was 20,71g. In simulation it was 19,53g. The difference in maximum g between simulations and experiments is 5.69%, which is well within acceptable limits. LS Dyna results are in good accordance with experimental tests. The simulation can be used to validate the design in its earliest stages.
