On Evaluation of the States of Cooked Cocoons by Dynamic Measuring Methods

Abstract

Measuring methods capable instantaneously the rheological characteristics of cooked cocoons were investigated, and as a reslt measuring equipments of the stae of cooked cocoons developed.
Some experimental results obtained were summarized as follows;
1. In a simulation, a pulse function was inputted in the 4-element model to measure the behavior of the model.
As a result, the simulation was found to be in an excellent agreement with the waveforms of actual cooked cocoons. It was therefore confirmed that the state of cooked cocoons could be evaluated by the 4-element model.
The response waveform simulated by inputting a pulse wave to the 4-element model displayed a damping curves, which was represented by the first peak Xh, logarithmic decrement δ, response frequency f and the difference h between the original level and convergence level.
2. A measuring equipment based on the simulation method was composed, which displayed on the oscilloscope and records the response waveform cased by a pulse wave impact to a point on a cocoon shell.
3. With the progress of cooking, . the impulse response waveforms of cocoons showed the tendency of lower value of Xh, δ and h, and higher value of f.
And it was known that the experimental results showed the same tendency as the simulation result.
4. In the next place, a measuring equipment by the frequency response method was composed, which displayed on the oscilloscope in Lissajous's figures the phase difference formed combinedly by the input sine waves given to a point on the cocoon and the response waves caused at a certain distance away by the input sine waves.
5. Two types of the frequency response m thod for measuring the states of cooked cocoons were examined.
First, the input frequency given to a point on the cocoon was raised step by step to determine the input frequencies which produced respectively the phase differences of π/2, π, 3π/2, 2π rad in Lissajous's figures.
Secondly, the sine waves of constant input frequency was given to a point on the cocoon, and the states of cooked cocoons were examined by the phase difference.
6. The results obtained by the frequency response method were in agreement with the simulation results of the 4-element model.
According to the frequency response method, it was known that the results showed synthetically the rheological characteristics of cooked cocoons.
7. Thus, the impulse response method and freguency response method were examined to measure the state of cooked cocoons. Particularly, the impulse response method was considerd to be more effective than frequency response method on utilizing the results obtained in the second report (rheological properties of cooked cocoons).