1 / 14

CASE STUDY – Combined Loading

CASE STUDY – Combined Loading. Drill bit isolators for underground mining – all metal components and elastomer must be safe! Design requirement: 8,000 lb thrust load and 300 lb-ft (3,600 lb-in) torque – these are basically the cutting forces.

derex
Télécharger la présentation

CASE STUDY – Combined Loading

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CASE STUDY – Combined Loading • Drill bit isolators for underground mining – all metal components and elastomer must be safe! • Design requirement: 8,000 lb thrust load and 300 lb-ft (3,600 lb-in) torque – these are basically the cutting forces. • Detailed FE analysis but ALWAYS verify with hand calculations!!

  2. Bit Isolator Drill Depth up to 48” Chuck Isolator 2010 SME Annual Meeting & Exhibit Phoenix, Arizona

  3. 35 mm (1 3/8 in) Isolator Load Requirements: Drill Bit Drill Bit Isolator ( Thrust Load = 8,000 to 10,000 lb Bending Load= 125 lbs)= K*d Drill Rod Torsion Load= 300 lb-ft Chuck Isolator HOT SPOT! 2010 SME Annual Meeting & Exhibit Phoenix, Arizona

  4. Results showed that in combination, the bit isolator and the drill chuck isolator provided a 7 dB(A) reduction in sound pressure level at the operator position. 2010 SME Annual Meeting & Exhibit Phoenix, Arizona

  5. 110 105 100 95 90 A-weighted Sound Level (dB) 85 80 75 70 65 60 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000 6300 8000 10000 Overall 1/3-Octave-Band Center Frequency (Hz) A-weighted Sound Level Spectrum 108.9 dB(A) Baseline: T2 - 45 NR BISO, 45 NR CISO: 104.4 dB(A) T5 - 55 NR BISO, 55 NR CISO: 102.7 dB(A) 104.4 dB(A) T7 - 70 NR BISO, 70 NR CISO: 2010 SME Annual Meeting & Exhibit Phoenix, Arizona

  6. 1 3/8” Drill Bit Isolator – Design Review: Drill Bit isolator: Chuck isolator: 2010 SME Annual Meeting & Exhibit Phoenix, Arizona 1 3/8" DBI, R. Michael, PE

  7. Critical Area!! Look at metal components: Where would you expect max stress to occur? 1 3/8" DBI, R. Michael, PE

  8. Critical component – inner member, thin wall, stress concentration!

  9. Results: FE Analysis 1 3/8” DBI All cases, thurst load = 8,000 lb, torque = 300 lb-ft (3,600 lb-in) HOT SPOT! 1 3/8" DBI, R. Michael, PE

  10. Max Principal, s1 Min Principal, s1

  11. Max shear stress, tmax VERIFY FEA RESULTS WITH HAND CALCS!!!!

  12. Verify Principal Stresses with Hand Calculations or Mohr’s Circle!! Thrust Load = 8,000 to 10,000 lb Torsion Load= 300 lb-ft HOT SPOT! y x

  13. HAND CALCS: From Axial Load (Compression) From Torque

  14. HAND CALCS Cont’d: Principal Stresses: =-11.95 +/- 35.8 ksi How do these values compare with FEA results? Next: use Mohr’s circle to resolve

More Related