Grain Bin Entrapment – Pressure MeasurementKevin MooreBiosystems and Agricultural EngineeringOklahoma State University

Grain Bin Entrapment• Entrapment – an individual is trapped inside a grain storage

structure and cannot free themselves• Causes• Flowing grain• Collapse of “bridged” grain• Collapse of vertical grain wall• Failure of storage structure

http://www.ag.ndsu.edu/pubs/ageng/safety/ae1102.pdf

Grain Bin Entrapment

http://extension.entm.purdue.edu/grainlab/content/pdf/2013SummaryFinal.pdf

Grain Bin Entrapment

http://www.agriview.com/news/crop/bushels-of-risk-involved-with-flowing-grain/article_da7612f4-2a99-11e2-a78b-0019bb2963f4.html

Objectives• Measure the

pressure on the chest and back of an entrapment victim• Investigate

differences in grain type and depth

Treatments• Four grain depths• Top of shoulders• Top of head• One foot below surface• Two feet below surface

• Four grain types• Soybeans• Wheat • Corn• Canola

Tekscan Pressure Measurement

http://www.tekscan.com/products

Tekscan CONFORMat System• 18.5in x 18.5in sensing

area with 1,024 “sensels”• Sensels are force

sensitive variable resistors• Pressure measurement

at each sensel location• Pressure map

Test Procedure• 1.83m (6ft) hopper bin• Load grain to desired depth, record pressure, unload

grain• Repeat for each replication and depth

Sensor Output

Mean Pressure

Mean Pressure

Calibration Challenges• Required prior to

testing for each grain• Equilibration with

vacuum bladder• Calibration load applied

with Instron • Two point power law

calibration curve in CONFORMat software

Calibration Challenges• Mistake in entering

calibration load• Significant deviation

in results• Calibration is critical

to data quality!

Future Work

• Complete testing with corn and canola• Model behavior with PFC3D• Investigate physiological response to measured

pressures

Funding for this research was supported by the Southwest Center for Agricultural Health, Injury Prevention and Education through Cooperative Agreement #U54-OH7541 from CDC/NIOSH

Questions?