Slicing frozen meat with an oscillating knife.

The forces, and hence fracture energies, required to cut frozen meat are presented in this paper and the merits of applying vibrations to a cutting blade are considered. A knife oscillating in a slicing action was used to cut horse M. semimembranosus and loin muscle M. longissimus dorsi over a range of temperatures (-1.5°C to -30°C) and vibration frequencies (0-1000 Hz). The blade required less force to cut when slicing than when not slicing; the decrease in force was proportional to the velocity of the slicing motion. If the average relative slicing velocity of the blade with respect to the meat was greater than 164 mm/s then the cutting force reduced significantly. The reduction was due to a lower requirement for energy to produce the new material surface (up to 80% reduction) and also a reduction in the plastic energy required to deform the off-cut by the blade (up to 30% reduction). The surface energy was reduced because the fracture mechanism was altered by the slicing action. The plastic energy was reduced because the slicing blade fractured the meat fibres with less strain (and hence less material deformation around the process zone) than a blade pressed directly into the meat. Vibration frequencies of 10-100 Hz were required to generate the required slicing motion with the equipment available. A vibrating cutting blade could have a combination of chopping and slicing motions superimposed upon it. These would reduce both the friction between the knife blade and the meat, as well as the surface and plastic energy required to cut the meat.