Metals and resins are applied together to the parts of automobile, and many metals are used to the important security parts. So more exact evaluation of fatigue strength is required.
In this report, a summary of evaluation of metals by input distinction is mentioned, and evaluation of actual load which has tried in many direction is introduced.

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A new testing method for determining the rupture life of paper was developed. The principle of the method lies on the measurement of the number of repeating impulese of low energy. Impulse force is given to the sheet in parallel with the plane. Rupture life of paper was measured using this method with a variety of stocks, sheet forming conditions and atmospheric circumstances. Commercial rosin-alum system (acidic, pH 4.7) paper and neutralsized (alkaline, pH 7.4) paper produced from the same pulp were aged at 80 °C and 80% R.H. with varying duration of time. It was found that the rupture life of both paper decreased with the increase in time, however, the rate of decrease in rupture life of acidic paper were clearly larger than that of alkaline paper. Higher humidity accelerated the deterioration of paper.
From these findings, it can be concluded that rupture life of paper is deeply dependent on the condition of treatments of paper, kind of stock, and drying condition of wet web. Changes of sheet structure brought about by repeating impulse were investigated through the changes in specific light scattering coefficient of paper.

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Thermal oxidation behaviors of unfilled and filled nitrile rubber (NBR) vulcanizates were studied by the measurement of the proton spin-spin relaxation time T2. The T₂ signal for a degraded specimen was resolved into two components (short T₂ (T_2S) and long T₂ (T_2L)), while the T₂ signal for an undegraded specimen was fitted by a single component. The T_2S component may correspond to motionally constrained regions in the network chains, and the T_2L component (comparable to the T₂ component for the undegraded specimen) to relatively free regions. The fraction of T_2S increases with the increase of the heating time. The increased fraction of T_2S at a given period depends on both the surface activity and the amount of the filler particles, associated with the cumulative oxygen uptake. In the thermal oxidation process of NBR systems, the crosslinking reactions predominantly occur, and the results from the FT-IR depth profile analysis reflect the appearence of the crosslink density gradients from the outer to the inner in the degraded specimen. It is considered that the T_2S component is assigned to the locally constrained regions with high crosslink density, and that the constrained regions in the network chains is inhomogeneously distributed from the outer to the inner. It has becomes clear that the increased fraction of T_2S is closely connected with the lowering of the breaking stretch ratio in tension important for the practical performance, and that the failure of the overall system occurs sensitively under the influence of the constrained regions. The pulsed NMR method is expected to be one of the most suitable tools for studying degradation behaviors of rubber parts in engineering applications.

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