Fatigue durability of asphalt-cement mixtures

This paper focuses on examinations of asphalt-cement mixtures (ACM). This is a recycled material which can be used in road pavement layers. In the article stiffness modulus tests and fatigue tests of asphalt-cement mixtures were shown. The authors decided to lead research on fatigue durability of asphalt-cement mixtures to set fatigue characteristics of these materials. So far in research or other works any adequate fatigue criterion for ACM mixtures has not been developed. As a result of the examinations a level of fatigue damage was suggested. For new fatigue damage a strain level in one million load cycle was estimated. Based on that a fatigue design criterion for asphalt-cement mixtures was estimated.

Fatigue Design of Gas Welded Joint for the Railroad Car Body Using the Hot Spot Stress

In order to establish a reasonable and integrated fatigue design criterion for the long life design of the gas welded body structure, stress distribution around the gas welded joints subjected to tensile load was numerically analyzed. And also, the P-Nf curves were obtained by fatigue tests. By using these results, P-Nf curves were rearranged in the σ-Nf relation with the hot spot stress at the welded joint. And a guideline for fatigue design of gas welded joints was proposed.

Fatigue Strength Evaluation for Gas Welded Joint of Similar and Dissimilar Materials

In order to establish a reasonable and integrated fatigue design criterion for the long life design of the gas welded body structure, stress distribution around the gas welded joints subjected to tensile load was numerically analyzed. And also, the P-Nf curves were obtained by fatigue tests. By using these results, P-Nf curves were rearranged in the σ-Nf relation with the hot spot stress at the welded joint. And a guideline for fatigue design of gas welded joints was proposed.

Fatigue Design of Leaf Spring Using Artificial Neural Network

The vehicle suspension system is directly influenced to ride and handling. Therefore, the major components of the vehicle suspension system should have enough fatigue strength during its lifetime to protect passenger from the traffic accident. Spring is one of the major suspension part of vehicle. Thus, in this paper, a fatigue design method for leaf spring was proposed. At first, numerical stress analysis for leaf spring assembly was performed. On the base of the analysis results, fatigue strength of leaf spring was assessed. And next, after studying numerically on geometrical parameters of leaf spring assembly, an economical prediction method of fatigue design criterion for leaf spring assembly using the theory of artificial neural network was developed and certified its usefulness. Without performing a lot of additional fatigue test for a long time, fatigue design criterion for a new leaf spring assembly having different geometry can be predicted on the base of the already obtained fatigue data.

Stress Analysis of the Automobile's Coil Spring Including Residual Stresses by Shot Peening

Durability assessment for the suspension system of the vehicle is very important. In order to secure reliability on the results of durability assessment and fatigue design criterion, accurate stresses for the interesting component must be basically calculated. In this paper, numerical stress analyses for the automobile’s coil spring were performed. Residual stresses by shot peening were also analyzed. The effects of the stress analysis results on fatigue strength of the coil spring were discussed. From the results, fatigue durability of the shot peened coil spring could be considerably improved by the effects of compressive residual stress. However, being attacked by corrosive environments, it could decrease by corrosion fatigue degradation.

A Fatigue Design Method of Spot-Welded Lap Joint Using Neural Network

In order to establish a long life fatigue design criterion of spot-welded thin sheet structures such as the automobile and the train bodies, an economical method was proposed. As a mechanical parameter to determine the fatigue design criterion of spot-welded structure, the maximum stress equation was defined by using artificial neural network. By using the maximum stress equation and the fatigue data previously obtained as the fatigue test results, the fatigue design criterion of spot-welded joint could be predicted without any additional fatigue tests. The results predicted by this method showed good agreement with actual fatigue test results.