A closed-form model for layered snow slabs

Weißgraeber, Philipp; Rosendahl, Philipp Laurens

doi:10.5194/tc-17-1475-2023

Cited by 3 publications

(1 citation statement)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By modeling stability tests, researchers can gain insight into the avalanche release process and quantify key parameters such as the effective elastic modulus of the slab and weak layer fracture energy (van Herwijnen et al, 2016). Modeling efforts have focused on the PST rather than the CT or ECT (Benedetti et al, 2019;McClung & Borstad, 2012;Weißgraeber & Rosendahl, 2023). One reason is the crack is initiated by cutting through the weak layer with a snow saw during the PST, a more measurable mechanism than the impact-initiated crack of the CT/ECT.…”

mentioning

confidence: 99%

How hard do we tap during snow stability tests?

Toft,

Verplanck,

Landrø

2023

Preprint

View full text Add to dashboard Cite

Abstract. This study examines the impact force applied from hand taps during Extended Column Tests (ECT), a common method of assessing snow stability. The hand-tap loading method has inconsistencies across the United States, Canadian, and Norwegian written standards, as well as inherent subjectivity. We developed a device, the “tap-o-meter”, to measure the force-time curves during these taps and collected data from 286 practitioners, including avalanche forecasters and mountain guides in Scandinavia, Central Europe, and North America. Peak forces and loading rates are the metrics chosen to quantitatively compare the data. The mean, median, and inner quartile peak forces are distinctly different for each loading step (wrist, elbow and shoulder), as are the loading rates. However, there is significant overlap across the range of measurements and examples of participants with higher force wrist taps than other participants' shoulder taps. This overlap challenges the reliability and reproducibility of ECT results, potentially leading to dangerous interpretations in avalanche decision-making, forecasting and risk assessments. Therefore, we recommend updating the standards for the ECT. We propose two viable paths for future action: (1) define a target impact force-time curve for each tap level and develop tools and training to minimize variability in tapping force (2) assess the significance of the information derived from the number of taps. If deemed not highly valuable, we should consider reverting to a simpler binary interpretation that focuses exclusively on crack propagation.

show abstract

mentioning

confidence: 99%

How hard do we tap during snow stability tests?

Toft,

Verplanck,

Landrø

2023

Preprint

View full text Add to dashboard Cite

show abstract

Closed‐Form Approach on Mode III$\mathrm{I}\! \mathrm{I}\! \mathrm{I}$ Loadings of Thin Layers

Rheinschmidt,

Adam,

Weißgraeber

et al. 2024

Proc Appl Math and Mech

View full text Add to dashboard Cite

Weak interface models are a potent tool to capture both deformations, stresses, and energy release rates for adhesives or other weak layers between stiffer joints. While the energy release rate for both modes I and II is rendered well, a fast and efficient model, capturing mode III loading of the weak layer is missing. The present study addresses this research gap by introducing a closed‐form analytical model for out‐of‐plane bended weak interface specimens. The classical approach of weak interface models is not applicable in the case of loading the specimen with out‐of‐plane bending. Tackling these difficulties, the present approach uses the principle of minimum potential energy in combination with the calculus of variations to derive the governing equations for an arbitrarily loaded weak interface specimen. This model renders stresses and displacements in a very good agreement with numerical reference solutions and is highly efficient and reduces the numerical costs for parameter studies and the evaluation of experiments. This enables one to measure the mode III energy release rate from a J‐integral‐based evaluation of this physical quantity. Our model allows a fast determination of the mode III fracture toughness from out‐of‐plane loaded double cantilever beam tests for adhesives or from rotated propagation saw tests for faceted and porous weak layers in stratified snowpacks.

show abstract

How hard do avalanche practitioners tap during snow stability tests?

Toft,

Verplanck,

Landrø

2024

Nat. Hazards Earth Syst. Sci.

View full text Add to dashboard Cite

Abstract. This study examines the impact force applied from hand taps during extended column tests (ECTs), a common method of assessing snow stability. The hand-tap loading method has inherent subjectivity and inconsistencies across US, Canadian, Swiss, and Norwegian written standards. We developed a device, the “tap-o-meter”, to measure the force-time curves during these taps and collected data from 286 practitioners, including avalanche forecasters and mountain guides in Scandinavia, Central Europe, and North America. The mean, median, and inner-quartile peak forces are distinctly different for each loading step (wrist, elbow, and shoulder), and the peak force approximately doubles from one loading step to the next. However, there is considerable overlap across the range of measurements and examples of participants with higher-force wrist taps than other participants' shoulder taps. This overlap challenges the reliability and reproducibility of ECT results, potentially leading to dangerous interpretations in avalanche decision-making, forecasting, and risk assessments. Our results provide an answer to the question “How hard do avalanche practitioners tap?” but not necessarily to the question “How hard should avalanche practitioners tap?” These data and insights are intended to facilitate discussion among the tests' creators, the scientific community, and the practitioner community to update thresholds, guidelines, and test interpretation.

show abstract

A closed-form model for layered snow slabs

Cited by 3 publications

References 65 publications

How hard do we tap during snow stability tests?

How hard do we tap during snow stability tests?

Closed‐Form Approach on Mode III$\mathrm{I}\! \mathrm{I}\! \mathrm{I}$ Loadings of Thin Layers

How hard do avalanche practitioners tap during snow stability tests?

Contact Info

Product

Resources

About