Simulating and Testing the Damping of Targets in

Tonie Butler Supervisors: Patrick Hurh, Katsuya Yonehara, Nnamdi AgboFinal Talks11 August 2021

Simulating and Testing the Damping of Targets in Accelerator Based Experiments

• Target Systems Department• All accelerator based experiments use targets• Targets are used to convert high-energy proton beams into new particles

– Results in the target undergoing stresses, high temperatures, radiation damage

• Targets need to be able to withstand the damage

Background

8/11/21 Tonie Butler | Simulating and Testing the Damping of Targets in Accelerator Based Experiments2

Figure1.TargetforLBNF/DuneProject

• When the force of the particle beam is applied, the target is subject to oscillations and vibrations– Causes concern regarding the fatigue and the amount of oscillations it can withstand

before failure

• Oscillations can be reduced by increasing damping– Damping is the gradual dissipation of energy over a period of time

– Damping can be modified in various ways• Clamping method

• Modified target dimensions

• Material

• Gap element verses a solid rod

• Added materials

• Composite structure

Damping


• Goal: To increase damping for more accurate target life-spans and to increase the number of cycles the target would be able to withstand and, therefore, increase its overall life

• Start by modeling a basic cantilever rod to mimic the target• Apply a catalyst to start the oscillations and simulations• Observe the oscillations so the damping ratio can be calculated

Project Overview


Figure2.TargetInternalConfiguration

• Use modeling tool (ANSYS) to make the basic design• Start with a simple cantilever beam design that is fixed at one end• Material: Titanium (Ti-6Al-4V)• Dimensions

– Length: 250mm

– Diameter: 8mm

Modeling the Beam


Figure3.BasicANSYSCantileverBeamDesignUsedtoMimictheTarget

• Modal Analysis– Determines the natural frequencies of the cantilever beam

– 𝐼 = #$%

&'

– 𝜔 = 𝑐* +,-./%

�

• Compare analytical results to experimental results (simulation)• Largest margin of error was 3.6% for mode 3

Determining the Basis


Frequency (Hz)Mode Analytical Experimental

1 90.83 88.3112 569.25 551.513 1594.08 1535.7

Figure4.ModalAnalysisComparison

• Static Analysis– Apply force to observe initial deflection of the first mode

– Ensure the simulation’s results hold constant to the analytical results

• Transient Analysis– Determine the beam’s time dependent response so the damping ratio can be calculated

• Use Roark and Young’s equations to determine the force to apply

– 𝛿 = 2/3

4+,– 7 Newton Force

Simulation Steps


Transient Analysis Results


• Gradual application of force• The force is released instantaneously, therefore, triggering the oscillations• Currently no damping is visible• After the force is removed, the amplitude remains constant• Material damping has not been applied, therefore, the data is skewed

Figure5.DeflectionofTargetwithoutMaterialDamping

Figure6.DeflectionofTargetwithDamping

Concept Design


• Base with split ring clamp for later modifications to the beam dimensions• Vertical orientation

– To observe the effects caused strictly by damping

• Deflected by a linear slide actuator• Two deflection sensing methods (contact and contactless)

– Strain gauge

– Laser doppler vibrometer

Figure7.BasicConceptDesignofPhysicalExperiment

• Add damping to the current simulation for more accurate results• Assemble the concept design so physical testing can begin • Benchmark the simulation results using the physical results• Add complexities to the ANSYS simulation and repeat the steps with the physical

experiment to run a sensitivity study– Will result in being able to determine what factors increase, decrease, or have no effect

on damping in our targets

– Can increase overall life span

– Enable more precise predictions of the target’s life-span

Future Work


Documents

Simulating and Testing the Damping of Targets in