N A S A G O D D A R D S P A C E F L I G H T C E N T E R

I n t e g r a t e d D e s i g n C a p a b i l i t y / I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

MAXIM Periscope Module

Structural Analysis

Jeff Bolognese

25 April 2003

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p2Final Version

25 April 2003MAXIM Periscope Module

Structural Analysis Outline

•Structural Analysis Goals•Finite Element Models•Analysis Results•Issues and Future Work•Conclusions•Detailed Analysis Results

– Mirror Analyses• Thermal Deformation• 20g Quasi Static Load Stresses

– Optical Bench Analyses• Normal Modes Analysis• Thermal Distortion• Gravity Loading• 1 DOF Actuation

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p3Final Version

25 April 2003MAXIM Periscope Module

Analysis Goals

• For Mirror and Mount– Mass properties of lightweight ULE mirror– Fixed base dynamics assessment– Minimize thermal deformations of mirror surface– Ti stresses < yield for 20g loading– ULE stresses small for 20g loading

• For Optical Bench– Fundamental Frequency > 50 Hz– Sensitivity of bench to thermal distortion– Gravity sag distortions– Bench distortions due to 1 DOF actuator actuation– Material trade studies

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p4Final Version

25 April 2003MAXIM Periscope Module

Finite Element Models

• MSC/NASTRAN format

• Optics model– ULE used for detailed optics model

• 3.5mm face sheet• 2.5mm back sheet• 1.27mm thick core• 20mm cell size (from vertex to vertex)

– Ti for flexures– Analysis mass of optic = 2.1 Kg

• Optical bench model– Titanium for mounts and flexures– Invar for bench– Lumped masses for optics– Simplified representation of optics mounts– 2D representation of 3d bench

• Plate elements with bars for stiffeners

– Analysis mass = 68.8 Kg

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p5Final Version

25 April 2003MAXIM Periscope Module

Mirror FEM

Mirror Face Mirror Back

3pt Ti Flexure Mount

Optic w/FaceSheet Removed

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p6Final Version

25 April 2003MAXIM Periscope Module

Optical Bench FEM

Flexure Fixed Mount

Simplified Optics Mounts

Main Bench

“Daughter” Benches

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p7Final Version

25 April 2003MAXIM Periscope Module

Mirror Analysis Summary

Analysis Goal/Req. Result Comments

1oc Bulk Temp Load min surface deformation PtoV=6.2nm, RMS=1.2nm

1oc X Gradient min surface deformation PtoV=3.2nm, RMS=0.6nm Gradient across mirror surface

1oc Y Gradient min surface deformation PtoV=3.1nm, RMS=0.6nm Gradient across mirror surface

1oc Z Gradient min surface deformation PtoV=17.0nm, RMS=3.8nm Gradient through mirror thicknessFixed Base Dynamics FF > 100 Hz FF=278 Hz Mirror on flexures, but not entire mount20g Quasi Static Load Mount Stress < Yield 35 MPa maximum 20g Y Loading20g Quasi Static Load Low Mirror Stress 7.6MPa maximum 20g Y Loading

1cZ Mirror Deformations (mm) 20gY Mirror Back Stresses (MPa) Mirror First Mode = 278 Hz

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p8Final Version

25 April 2003MAXIM Periscope Module

Optical Bench Analysis Summary

Analysis Goal/Req. Result CommentsFixed Base Dynamics FF > 50 Hz FF=49 Hz

1oc Bulk Temp See Tables in Backup Material

1oc X Gradient See Tables in Backup Material

1oc Y Gradient See Tables in Backup Material1g X load See Tables in Backup Material1g Y load See Tables in Backup Material1g Z load See Tables in Backup MaterialSingle Side Actuation See Tables in Backup MaterialBoth Side Actuation See Tables in Backup Material

Deformation Due to Single ActuationDeformation Due to 1c Y Gradient Deformation Due to 1g Z

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p9Final Version

25 April 2003MAXIM Periscope Module

Issues and Future Work

• Further optimization of bench design is necessary to minimize weight and increase fundamental frequency

– Better understanding of thermal environment to quantify allowable material CTE

• More detailed modeling of the mirrors and mounts necessary to understand overall mount stiffness as well as quantify local stresses and deformations

– Interfaces between mount and mirror will require specific attention

• More detailed analysis of “daughter” bench flexures to balance stiffness vs. potential to impose distortions to benches during 1 DOF actuations

– Preliminary analyses show coupling between actuations and bench distortions which could complicate control of optics pointing

• Better understanding of which displacements of optics can be corrected by mechanisms is needed to be folded into analysis efforts. Calculated displacements should then be considered to determine if, for flight load cases, mechanisms have the range to correct the errors.

• More detailed, 3D model of bench is required to fully capture thermal deformations and the complexities of optical mount interfaces when predicted flight loads are applied.

• Quantify jitter sources and verify that they are not pose a pointing issue due to dynamic coupling with structure.

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p10Final Version

25 April 2003MAXIM Periscope Module

Conclusions

• Proposed design looks promising but requires further analysis to verify that thermal control is adequate and mechanisms robust enough to correct for launch shifts and on-orbit transients.

• Still lots of analysis work to be done!

N A S A G O D D A R D S P A C E F L I G H T C E N T E R

I n t e g r a t e d D e s i g n C a p a b i l i t y / I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Backup Slides

TBD

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p12Final Version

25 April 2003MAXIM Periscope Module

Mirror and Mount ThermalDeformations

Plot showing Z translations of mirror surface (in mm) after rigid body motion effects are removed

1c Bulk Temp Increase 1c X Gradient

1c Y Gradient 1c Z Gradient

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p13Final Version

25 April 2003MAXIM Periscope Module

Mirror and Mount 20g Stresses

20 G X Loading 20 G Z Loading20 G Y Loading

Mirror Back Stresses (in MPa)

Mirror Flexure Stresses (in MPa)

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p14Final Version

25 April 2003MAXIM Periscope Module

Optical Bench Fixed Base DynamicsBench Mode 1 – 49 Hz

Bench Mode 2 – 56 HzBench Mode 3 – 65 Hz

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p15Final Version

25 April 2003MAXIM Periscope Module

Bench Bulk Thermal Deformations

1c Bulk Temp IncreaseAbsolute Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror -4.94E-05 -8.60E-04 1.50E-03 6.85E-07 1.26E-08 3.37E-081002 Daughter Bench Mirror 1 -2.43E-04 -4.33E-04 1.34E-03 -1.45E-06 -2.66E-07 1.62E-081003 Daughter Bench Mirror 2 -4.03E-04 -4.34E-04 1.34E-03 -1.45E-06 2.65E-07 -1.52E-081004 3 DOF Actuated Mirror -5.77E-04 -1.47E-03 1.37E-03 3.36E-06 6.04E-08 -5.55E-08

Relative Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror -2.13E-12 1.33E-11 -1.82E-10 -7.69E-14 -1.35E-15 6.70E-161002 Daughter Bench Mirror 1 -1.95E-04 4.32E-04 -1.24E-04 -2.13E-06 -2.79E-07 -1.75E-081003 Daughter Bench Mirror 2 -3.56E-04 4.43E-04 -1.28E-04 -2.13E-06 2.52E-07 -4.89E-081004 3 DOF Actuated Mirror -5.28E-04 -5.86E-04 -1.37E-04 2.68E-06 4.78E-08 -8.93E-08

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p16Final Version

25 April 2003MAXIM Periscope Module

Bench 1c X Gradient Deformations

1c +X GradientAbsolute Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror -2.42E-04 -7.63E-04 1.33E-03 6.06E-07 -1.20E-06 -8.11E-071002 Daughter Bench Mirror 1 -4.10E-04 -2.99E-04 9.20E-04 -1.00E-06 -1.25E-06 -5.96E-071003 Daughter Bench Mirror 2 -4.89E-04 -1.40E-04 4.20E-04 -4.45E-07 -9.79E-07 -6.13E-071004 3 DOF Actuated Mirror -4.79E-04 -1.69E-04 1.56E-04 3.79E-07 -8.42E-07 -1.02E-06

Relative Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror 5.72E-12 3.26E-12 -3.21E-10 -4.65E-14 -3.41E-13 4.17E-141002 Daughter Bench Mirror 1 -1.22E-04 3.23E-04 -1.67E-04 -1.61E-06 -5.25E-08 2.14E-071003 Daughter Bench Mirror 2 -2.02E-04 2.18E-04 -2.77E-04 -1.05E-06 2.18E-07 1.97E-071004 3 DOF Actuated Mirror -2.37E-04 4.78E-05 -3.66E-04 -2.27E-07 3.55E-07 -2.09E-07

1c -X GradientAbsolute Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror 1.93E-04 -9.68E-05 1.71E-04 7.88E-08 1.21E-06 8.44E-071002 Daughter Bench Mirror 1 1.67E-04 -1.35E-04 4.20E-04 -4.45E-07 9.85E-07 6.12E-071003 Daughter Bench Mirror 2 8.61E-05 -2.94E-04 9.21E-04 -1.00E-06 1.24E-06 5.98E-071004 3 DOF Actuated Mirror -9.79E-05 -1.30E-03 1.22E-03 2.98E-06 9.02E-07 9.64E-07

Relative Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror 2.72E-11 2.72E-12 -8.31E-12 1.51E-15 1.69E-13 4.77E-141002 Daughter Bench Mirror 1 -7.25E-05 1.09E-04 4.27E-05 -5.24E-07 -2.25E-07 -2.32E-071003 Daughter Bench Mirror 2 -1.54E-04 2.25E-04 1.49E-04 -1.08E-06 3.25E-08 -2.46E-071004 3 DOF Actuated Mirror -2.91E-04 -6.34E-04 2.29E-04 2.90E-06 -3.08E-07 1.19E-07

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p17Final Version

25 April 2003MAXIM Periscope Module

Bench 1c Y Gradient Deformations

1c +Y GradientAbsolute Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror -1.17E-04 -9.99E-04 6.67E-04 4.00E-06 5.03E-09 -9.78E-071002 Daughter Bench Mirror 1 -2.19E-04 -6.95E-04 3.07E-04 3.36E-06 -3.62E-08 -3.85E-071003 Daughter Bench Mirror 2 -2.58E-04 -6.92E-04 3.07E-04 3.37E-06 3.60E-08 3.66E-071004 3 DOF Actuated Mirror -3.49E-04 -1.36E-03 6.05E-04 5.79E-06 3.88E-08 9.49E-07

Relative Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror -2.67E-11 5.99E-12 -9.06E-12 2.99E-13 1.31E-17 -9.12E-151002 Daughter Bench Mirror 1 -4.76E-05 1.33E-04 -1.39E-04 -6.33E-07 -4.12E-08 5.93E-071003 Daughter Bench Mirror 2 -8.68E-05 -1.82E-04 -1.40E-04 -6.33E-07 3.10E-08 1.34E-061004 3 DOF Actuated Mirror -2.32E-04 -1.02E-03 -6.54E-05 1.79E-06 3.38E-08 1.93E-06

1c -Y GradientAbsolute Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror 6.74E-05 1.39E-04 8.34E-04 -3.31E-06 7.57E-09 1.01E-061002 Daughter Bench Mirror 1 -2.39E-05 2.62E-04 1.03E-03 -4.81E-06 -2.30E-07 4.01E-071003 Daughter Bench Mirror 2 -1.45E-04 2.59E-04 1.03E-03 -4.81E-06 2.28E-07 -3.81E-071004 3 DOF Actuated Mirror -2.29E-04 -1.05E-04 7.67E-04 -2.43E-06 2.16E-08 -1.00E-06

Relative Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror 3.29E-12 -3.63E-11 2.39E-12 -6.79E-14 1.01E-16 2.77E-131002 Daughter Bench Mirror 1 -1.48E-04 2.99E-04 1.41E-05 -1.50E-06 -2.38E-07 -6.11E-071003 Daughter Bench Mirror 2 -2.69E-04 6.25E-04 1.17E-05 -1.50E-06 2.21E-07 -1.39E-061004 3 DOF Actuated Mirror -2.96E-04 4.38E-04 -7.21E-05 8.85E-07 1.40E-08 -2.02E-06

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p18Final Version

25 April 2003MAXIM Periscope Module

Bench 1g X Deformations

1g X LoadingAbsolute Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror 4.04E-03 -8.03E-04 -1.75E-06 -1.10E-07 1.76E-05 1.16E-051002 Daughter Bench Mirror 1 5.65E-03 -1.87E-03 4.55E-05 -8.95E-09 2.29E-05 -4.52E-061003 Daughter Bench Mirror 2 5.72E-03 -1.55E-03 -4.53E-05 6.58E-08 2.33E-05 -5.66E-061004 3 DOF Actuated Mirror 9.73E-03 -4.99E-04 -4.90E-05 1.80E-07 5.25E-05 1.40E-05

Relative Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror -8.56E-11 -2.74E-11 -1.49E-13 1.47E-15 5.52E-13 4.80E-121002 Daughter Bench Mirror 1 9.64E-04 9.50E-04 -3.02E-03 1.01E-07 5.30E-06 -1.61E-051003 Daughter Bench Mirror 2 1.03E-03 5.05E-03 -8.83E-03 1.76E-07 5.72E-06 -1.73E-051004 3 DOF Actuated Mirror 5.68E-03 8.12E-03 -1.19E-02 2.90E-07 3.50E-05 2.45E-06

1g X Deformed Plot

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p19Final Version

25 April 2003MAXIM Periscope Module

Bench 1g Y Deformations

1g Y LoadingAbsolute Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror -1.29E-03 7.87E-03 4.61E-04 -5.80E-05 4.05E-08 -1.66E-051002 Daughter Bench Mirror 1 -7.50E-04 8.10E-03 -2.53E-04 -1.94E-05 4.35E-06 -4.32E-061003 Daughter Bench Mirror 2 -1.81E-03 8.70E-03 -2.53E-04 -1.94E-05 -4.35E-06 6.82E-071004 3 DOF Actuated Mirror -9.05E-04 4.71E-03 6.49E-04 -1.92E-05 -1.61E-08 1.64E-05

Relative Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror 3.98E-10 2.76E-10 -4.57E-11 -4.06E-12 -1.06E-16 -6.85E-131002 Daughter Bench Mirror 1 1.46E-03 -2.67E-03 -3.95E-03 3.86E-05 4.31E-06 1.23E-051003 Daughter Bench Mirror 2 3.96E-04 -7.48E-03 -3.96E-03 3.86E-05 -4.39E-06 1.73E-051004 3 DOF Actuated Mirror 3.82E-04 -1.44E-02 1.60E-04 3.88E-05 -5.66E-08 3.30E-05

1g Y Deformed Plot

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p20Final Version

25 April 2003MAXIM Periscope Module

Bench 1g Z Deformations

1g Z LoadingAbsolute Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror 1.59E-02 1.22E-02 1.26E-02 -7.49E-05 9.74E-05 -6.04E-071002 Daughter Bench Mirror 1 2.13E-02 5.00E-02 5.26E-02 -2.98E-04 1.30E-04 -7.09E-061003 Daughter Bench Mirror 2 1.75E-02 6.45E-02 9.15E-02 -3.93E-04 1.04E-04 -5.34E-061004 3 DOF Actuated Mirror -2.63E-02 6.03E-02 5.74E-02 -3.67E-04 -1.59E-04 -9.88E-07

Relative Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror 3.93E-09 -4.91E-09 -3.99E-09 -1.39E-12 -2.61E-12 -1.12E-141002 Daughter Bench Mirror 1 5.47E-03 3.77E-02 1.89E-02 -2.23E-04 3.29E-05 -6.48E-061003 Daughter Bench Mirror 2 1.69E-03 5.20E-02 2.60E-02 -3.19E-04 6.40E-06 -4.74E-061004 3 DOF Actuated Mirror -4.22E-02 4.77E-02 -2.08E-02 -2.93E-04 -2.57E-04 -3.84E-07

1g Z Deformed Plot

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p21Final Version

25 April 2003MAXIM Periscope Module

.001mm Motion of +Z Side Daughter

Board Actuator+Z Side ActuationAbsolute Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror -1.45E-05 2.42E-05 -1.06E-07 -1.01E-07 -3.41E-08 -1.09E-071002 Daughter Bench Mirror 1 3.25E-06 -1.10E-03 -8.63E-05 4.49E-06 1.97E-07 6.69E-071003 Daughter Bench Mirror 2 -3.69E-05 -1.10E-03 -9.93E-05 4.47E-06 -2.60E-07 -6.75E-071004 3 DOF Actuated Mirror 2.91E-05 4.18E-05 -5.17E-06 -2.03E-07 2.69E-07 8.56E-08

Relative Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror -3.93E-13 5.86E-12 -2.34E-14 -1.34E-14 -2.88E-15 -3.61E-151002 Daughter Bench Mirror 1 2.38E-05 -1.14E-03 -8.58E-05 4.59E-06 2.31E-07 7.78E-071003 Daughter Bench Mirror 2 -1.63E-05 -1.18E-03 -8.78E-05 4.57E-06 -2.26E-07 -5.66E-071004 3 DOF Actuated Mirror 4.36E-05 -5.62E-05 1.79E-05 -1.02E-07 3.04E-07 1.95E-07

Deformation Due to .001mm Y Motion of +Z Side Actuator

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p22Final Version

25 April 2003MAXIM Periscope Module

.001mm Motion of -Z Side Daughter

Board Actuator-Z Side ActuationAbsolute Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror -2.45E-06 -9.64E-06 9.76E-08 1.01E-07 3.37E-08 -1.04E-071002 Daughter Bench Mirror 1 -1.07E-05 5.28E-04 9.34E-05 -4.15E-06 5.63E-08 3.48E-071003 Daughter Bench Mirror 2 -2.32E-06 5.25E-04 1.06E-04 -4.13E-06 6.89E-09 -3.46E-071004 3 DOF Actuated Mirror -5.92E-05 -2.64E-05 5.16E-06 2.03E-07 -2.69E-07 1.26E-07

Relative Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror -4.24E-13 2.89E-13 2.12E-15 -9.33E-16 -6.98E-16 -3.47E-141002 Daughter Bench Mirror 1 -2.54E-06 5.19E-04 9.30E-05 -4.25E-06 2.26E-08 4.51E-071003 Daughter Bench Mirror 2 5.89E-06 4.83E-04 9.50E-05 -4.23E-06 -2.68E-08 -2.42E-071004 3 DOF Actuated Mirror -5.67E-05 -8.66E-05 -1.77E-05 1.03E-07 -3.03E-07 2.30E-07

Deformation Due to .001mm Y Motion of -Z Side Actuator

I n s t r u m e n t S y n t h e s i s & A n a l y s i s L a b o r a t o r y

Structural Analysis, p23Final Version

25 April 2003MAXIM Periscope Module

.001mm Motion of Both Daughter Board Actuators

Both Side ActuationAbsolute Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror -1.69E-05 1.46E-05 -8.02E-09 -1.65E-10 -3.85E-10 -2.13E-071002 Daughter Bench Mirror 1 -7.50E-06 -5.73E-04 7.08E-06 3.41E-07 2.53E-07 1.02E-061003 Daughter Bench Mirror 2 -3.92E-05 -5.73E-04 7.08E-06 3.41E-07 -2.53E-07 -1.02E-061004 3 DOF Actuated Mirror -3.01E-05 1.54E-05 -9.38E-09 3.37E-10 3.71E-10 2.12E-07

Relative Displacements mm radGrid Optic TX TY TZ RX RY RZ

1001 Fixed Mirror 1.91E-12 -2.94E-12 9.64E-16 3.69E-17 -2.54E-17 -3.83E-141002 Daughter Bench Mirror 1 2.13E-05 -6.25E-04 7.15E-06 3.41E-07 2.54E-07 1.23E-061003 Daughter Bench Mirror 2 -1.04E-05 -6.94E-04 7.27E-06 3.42E-07 -2.53E-07 -8.08E-071004 3 DOF Actuated Mirror -1.31E-05 -1.43E-04 2.58E-07 5.02E-10 7.56E-10 4.25E-07

Deformation Due to .001mm Y Motion of Both Actuators