Fatigue design of engineering structures is typically based on lifetime calculation using a cumulative damage law. The linear rule by Miner the universal standard for fatigue even though numerous experimental studies have shown its deficiencies and possible non-conservative outcomes. In an effort to overcome these deficiencies, many nonlinear models life prediction been developed since; however...

A multiscale fatigue analysis model is developed for brittle composite materials. The mathematical homogenization theory is generalized to account for multiscale damage effects in heterogeneous media and a closed form expression relating nonlocal microphase fields to the overall strains and damage is derived. The evolution of fatigue damage is approximated by the first order initial value probl...

Multiple-pulse S-on-1 laser damage experiments were carried out in the bulk of synthetic fused silica at 355 nm and 266 nm. Two beam sizes were used for each wavelength and the pulse duration was 8 ns. The results showed a fatigue effect that is due to cumulative material modifications. The modifications have a long lifetime and the fatigue dynamics are independent of the used beam sizes but di...

Review of the state-of-the-art on fungal damage of wood materials showed that a combination of period of cumulative time when moisture and thermal regimes are above specified minimum is needed for fungal activities to cause biological decay in wood. The long-term performance of a typical wall assembly was evaluated using an existing computer model of heat, moisture, and air transfer in conjunct...

OBJECTIVE The objective of this study was to determine if acute cartilage impact damage could be predicted by a quantification of the frequency content of the impact force signal. DESIGN Osteochondral specimens excised from bovine lateral tibial plateaus were impacted with one of six impact energies. Each impact force signal underwent frequency analysis, with the amount of higher-frequency co...

Chronic iron overload has slow and insidious effects on heart, liver, and other organs. Because iron-driven oxidation of most biologic materials (such as lipids and proteins) is readily repaired, this slow progression of organ damage implies some kind of biological "memory." We hypothesized that cumulative iron-catalyzed oxidant damage to mtDNA might occur in iron overload, perhaps explaining t...

BACKGROUND Significant numbers of people are exposed to tetrachloroethylene (perchloroethylene, PCE) every year, including workers in the dry cleaning industry. Adverse health effects have been associated with PCE exposure. However, investigations of possible cumulative cytogenetic damage resulting from PCE exposure are lacking. METHODS Eighteen dry cleaning workers and 18 laundry workers (un...