SAMCoT - Annual Report 2015

SAMC

• ANNUAL REPORT 2015

Ice-Induced Vibrations

Torodd Nord defended his thesis successfully in 2015 and

is now a SAMCoT Post-Doc. The research on ice-induced

vibrations involved experimental work and data process-

ing. Two papers were published and one paper submitted in

the Journal of Cold Regions Science and Technology (Nord

et al., 2015a; Nord et al., 2015b). In these model-scale

contributions, we elaborate on two fundamental regimes of

ice-induced vibrations and we demonstrate how the global

behavior of the structure influences on the pressure at the

ice-structure interface. At full scale, we instrumented the

Hanko-1 channel marker in the Gulf of Finland with accel-

erometers and strain gauges that will be used to study

ice-induced vibrations (Figure WP3_1). The methodol-

ogy used to decide upon sensor types and locations was

presented at the 23rd International Conference on Port and

Ocean Engineering under Arctic Conditions (Nord et al.,

2015c).

Nord introduced a novel methodology to the ice-research

community by applying a joint input-state estimation

algorithm to identify ice forces and structural responses.

This algorithm was successfully applied at full-scale by

using data collected in the STRICE (STRuctures in ICE)

project (2001-2003). Here, ice forces measured by panels

were compared with ice forces identified using the joint

input-state estimation algorithm (Nord, 2015 d).

During the winter season 1973-1974, professor emeritus

Mauri Määttänen installed strain gauges and accelero

meters to study ice-induced vibrations on the Kemi-1 light-

house in the northern Gulf of Bothnia (Määttänen, 1975). 43

years later, he was SAMCoT’s leader for the instrumenta-

tion of the Hanko-1 channel marker (Figure WP3_1). The

data will be used by Nord and Määttänen to identify ice

forces and to study ice-induced vibrations.

Hayo Hendrikse is about to submit his thesis on numeri-

cal simulations of ice-induced vibrations. Two papers

were accepted in the Journal of Cold Region Science and

Technology. He expects to defend his PhD thesis the spring

of 2016.

Figure WP3_1 Mauri Määttänen and an VTT Engineer installing strain gauges to the Hanko-1 channel marker in the Gulf of Finland.

Photo: Aki Kinnunen, VTT