Design guidelines for predicting stress in cemented doublets undergoing temperature change: part two

Kaufman, Morris I.

doi:10.1117/12.2601823

Cited by 1 publication

(5 citation statements)

References 8 publications

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“…It is fortunate that Thorlabs, Inc. has a catalog of doublets that are tested from −40°C to 85°C (a single thermal cycle). 34,35 Thorlabs also provides the necessary geometry and material data for stress estimations. We present calculated stresses for doublets selected from the Thorlabs achromat catalog to provide a stress database of successfully tested lenses.…”

Section: Design Implications Of Stress Singularitiesmentioning

confidence: 99%

“…This rule of thumb was formulated because of a sensitivity study by Kaufman et al 6 . It was observed that the shear glass stress was approximately linear with respect to the parameters Δα, ΔT, and Eavg when we assume the Tsai/Suhir simplifications.…”

Section: A Simplified Rule-of-thumb Expressionmentioning

confidence: 99%

“…(1). The details of the Monte Carlo simulation are given by Kaufman 6 . The conservative value assumes a 3X standard deviation from the average value.…”

Section: A Simplified Rule-of-thumb Expressionmentioning

confidence: 99%

“…It is fortunate that Thorlabs, Inc. has a catalog of doublets that are tested from −40°C to 85°C (a single thermal cycle) 34 , 35 . Thorlabs also provides the necessary geometry and material data for stress estimations.…”

Section: Comparison Of Tsai Model With Existing Datamentioning

confidence: 99%

“…This work incorporates six aspects: (1) the newer analytical solutions from Tsai are presented alongside FEA comparisons; (2) the results of a parametric FEA study, performed to address the effects of curvature, are presented; (3) some guidance in identifying acceptable stress levels for a given glass are provided; (4) drawing on the prior sensitivity study, a simplified expression to inform the early stages of a design is presented, using only the quantities with the strongest effect on performance 6 ; (5) practical guidelines for minimizing stress concentrations along the edge of a bondline are given; and (6) published data from a catalog of tested doublets are used to derive specific material, temperature, and stress recommendations.…”

Section: Introductionmentioning

confidence: 99%

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Guidelines for predicting stress in cemented doublets undergoing temperature change: theory, practice, and data

Kaufman,

Frayer,

Malone

et al. 2024

Opt. Eng.

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This work explores quick predictive methods for calculating potentially risky stresses and deflections in cemented doublets experiencing temperature change that agree well with finite element analysis. There are three failure modes of interest: cohesive failure of the adhesive, delamination (surface bond failure or debonding), and glass fracture. Adhesive theory, confirmed by finite element analysis, predicts stress singularities that complicate interpretation of the stress calculations. The presence of a stress singularity indicates the breakdown of linear elastic assumptions, but damage initiation and stress singularities are related. The authors find that geometry details near a bond edge can exacerbate or minimize damage initiation and stress concentrations. Because the interpretation of the stress results is complicated, the authors investigated predicted stresses in doublets that have been successfully tested between −40°C and 85°C. This study found that the thermal strain ðΔT • ΔαÞ should be less than 189 ppm, where ΔT is the temperature excursion and Δα is the difference in the two glass coefficients of thermal expansion. If the thermal strain is equal to or greater than 189 ppm, further analysis and testing is warranted. But the authors also show that the fabrication process can significantly influence stress failure, particularly with large diameter doublets.

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Section: Design Implications Of Stress Singularitiesmentioning

confidence: 99%

Section: A Simplified Rule-of-thumb Expressionmentioning

confidence: 99%

“…(1). The details of the Monte Carlo simulation are given by Kaufman 6 . The conservative value assumes a 3X standard deviation from the average value.…”

Section: A Simplified Rule-of-thumb Expressionmentioning

confidence: 99%