July 1st.	Welcome reception
July 2nd.	Oral session
July 3rd.	Oral session, Conference Dinner
July 4th.	Oral session

 

 

 

 

 

 

Cafe de Gohan (near Hokkaido University Main Gate): https://cafedegohan.com/

It takes roughly 10 min on foot from Sapporo station.

 

SAPPORO TOKYU REI HOTEL: https://www.tokyuhotels.co.jp/sapporo-r/index.html

It takes a few minutes on foot from Susukino station (2 station away from Sapporo station).

 

Prof. Frank Balle Institut für Nachhaltige Technische Systeme | INATECH | Department of Sustainable Systems Engineering Walter-und-Ingeborg-Herrmann-Professur für Leistungsultraschall und Technische Funktionswerkstoffe | Walter und Ingeborg Herrmann Chair for Power Ultrasonics and Engineering of Functional Materials (EFM) Albert-Ludwigs-Universität Freiburg | Technische Fakultät | University of Freiburg | Faculty of Engineering   Lecture title: FATIGUE BEHAVIOR OF POLYMER COMPOSITES AT LOW AND ULTRASONIC FREQUENCIES

Abstract

Even though the first ultrasonic fatigue investigation of metals dates back to the 1950s, the systems for testing fiber-reinforced polymer composites (FRP) at 20 kHz are not older than a decade. This delay can be attributed to the growing interest in composites in recent years and the critical self-heating temperature of polymers as one major challenge in contrast to most metals. In addition, several questions during ultrasonic fatigue of FRP arise: What is the influence of frequency on the fatigue of polymer composites? Is there a strain rate effect and how strong? Are the fatigue properties invariant between the HCF and VHCF regimes? Are the damage mechanisms of similar nature? 
To address these questions, experimental parameters must be carefully selected to avoid undesirable effects and incompatibilities between test frequencies. At ultrasonic frequencies, monitoring fatigue experiments also becomes challenging due to high displacement velocities up to 6 m/s. Several test campaigns were carried out at low and ultrasonic frequencies on carbon fiber reinforced thermoset and especially thermoplastic composites. Our latest results show that maintaining a stable surface temperature during most of the fatigue phase helps avoid undesirable thermal effects and to study the fatigue behavior in a reliable manner.

 

Prof. Satoshi Kobayashi Department of Mechanical Engineering, Graduate School of Science and Engineering, Tokyo Metropolitan University   Lecture title: MICROSCOPIC AND MACROSCOPIC FATIGUE DAMAGE BEHAVIOR IN CONTINUOUS FIBER-REINFORCED COMPOSITES

Abstract

For about 25 years, the presenter has been conducting experimental studies on the microscopic damage behavior of continuous fiber-reinforced composites under fatigue loading. This lecture introduces the following three topics.

1. Analytical methods to predict transverse crack initiation and accumulation behavior in continuous fiber-reinforced composites under mechanical and thermal loading. This method is based on the damage mechanical analysis proposed by Gudmundson and Zang. In this analysis, the average transverse crack opening displacement is assumed to be the crack opening displacement in transversely isotropic material with the same properties as the transverse ply. The advantage of this method is the point at which complex stress analysis is not required.

2. A simple method for evaluating the internal pressure strength of vessels using the ring burst test. In general, the evaluation of composite pressure vessels requires many expensive vessels and is costly. This is particularly true when characterizing fatigue life. In this method, hoop-directional properties can be evaluated for pressure vessels using specimens cut from the pressure vessel in the form of rings, thus reducing costs.

3. The effect of carbon fiber type on fatigue life. PAN-based carbon fibers are commonly used in aircraft, but for metallic structures such as bridges and pressure vessels, it is expected that PAN-based high-modulus carbon fibers and/or PITCH-based high-modulus carbon fibers will be used because of little difference in modulus. The fatigue properties of CFRP using these carbon fibers are presented.