Summary of Failure Modes of Jack Rubber Blocks
Jack rubber blocks are essential components that provide cushioning, vibration absorption, and load distribution. Understanding their potential failure modes is crucial for maintaining safety, reliability, and longevity of jack systems. The following summarizes the common failure modes, their causes, and general preventive measures.
1. Hardening and Loss of Elasticity
Description: Rubber becomes stiff, less compressible, or brittle.
Causes: Thermal aging, UV exposure, ozone attack, chemical interaction, or prolonged high temperatures.
Consequences: Reduced cushioning, increased risk of cracking, and decreased shock absorption.
2. Cracking and Surface Splitting
Description: Visible cracks on the surface, which can be radial or network-like.
Causes: Fatigue from repeated cyclic loading, low-temperature brittleness, overloading, or poor manufacturing.
Consequences: Compromised structural integrity and potential sudden failure.
3. Swelling or Softening
Description: Bulging, deformation, and reduced load-bearing capacity.
Causes: Contact with incompatible oils, fuels, solvents, or chemicals.
Consequences: Loss of dimensional stability, poor load distribution, and compromised shock absorption.
4. Detachment or Delamination
Description: Separation from bonded surfaces or mechanical dislodgement.
Causes: Improper bonding, insufficient adhesion, mechanical overload, or misalignment during installation.
Consequences: Slippage, uneven load transfer, and potential operational hazards.
5. Permanent Deformation or Bulging
Description: Irreversible changes in shape, compression set, or uneven surfaces.
Causes: Overloading, long-term static stress, or inappropriate hardness selection.
Consequences: Loss of cushioning effect and reduced service life.
6. Unusual Noise During Operation
Description: Squeaks, pops, or other abnormal sounds.
Causes: Hardening, misalignment, trapped air pockets, or inadequate lubrication.
Consequences: Indicates stress or damage that may lead to accelerated wear.
7. Fatigue and Microcracking
Description: Progressive damage under repeated cyclic loading.
Causes: Overloading, repetitive lifting cycles, or poor material selection.
Consequences: Reduced structural integrity and eventual failure.
8. Chemical Degradation
Description: Discoloration, softening, or surface tackiness.
Causes: Exposure to aggressive chemicals, fuels, acids, or solvents.
Consequences: Swelling, cracking, and compromised performance.
9. Thermal Damage
Description: Hardening, embrittlement, or surface cracking.
Causes: Exposure to high temperatures or repeated thermal cycling.
Consequences: Loss of elasticity and increased risk of catastrophic failure.
Conclusion
Jack rubber blocks are subject to multiple failure modes including hardening, cracking, swelling, detachment, deformation, noise, fatigue, chemical degradation, and thermal damage. Proper material selection, correct installation, environmental protection, and routine inspection are essential to prevent these failures, ensure safety, and extend service life.
References
Gent, A. N. Engineering with Rubber: How to Design Rubber Components. Hanser Publishers, 2012.
ASTM D573 – Standard Test Method for Rubber—Deterioration in an Air Oven.
Lake, G. J. “Fatigue and Fracture of Elastomers.” Rubber Chemistry and Technology, 2000.
ISO 7619-1 – Rubber, Vulcanized or Thermoplastic — Determination of Indentation Hardness.
ISO 2230 – Rubber Products—Guidelines for Storage and Maintenance.
