Turbine blade and gas turbine

A turbine blade comprising:

• a shroud portion disposed at an end portion of an airfoil portion;
• a holder casing that can be moved by sliding relative to the shroud portion, that can also be attached thereto/detached therefrom, and that forms a space with the shroud portions therebetween;
• an elastic portion that is disposed in the space, and that biases the shroud portion in a direction that separates it from the holder casing;
• and
• a friction portion that is disposed between the elastic portion and the shroud portion, that can be moved closer to or away from the shroud portion, and that is disposed in a movable manner relative to the shroud portion.

A turbine blade, comprising:

• a shroud portion disposed at an end portion of an airfoil portion;
• a holder casing that can slide relative to the shroud portion, that can also be attached thereto or detached therefrom, and that forms a space with the shroud portion therebetween;
• and
• an elastic portion that is disposed in the space, biases the shroud portion in a direction that separates it from the holder casing, and is disposed in a movable manner relative to the shroud portion,
• wherein
• the elastic portion extends parallel to the direction in which a plurality of the shroud portions form a row and is a plate-like spring formed in substantially a wave shape,
• peak portions of the spring are in contact with the shroud portion or the holder casing, and
• a plurality of the springs are disposed in substantially parallel rows and, relative to peak portions of a first spring, peak portions of the other spring are disposed shifted therefrom.

A method of damping vibration comprising:

• a sliding-occurring step of, when shroud portions each disposed at an end portion of an airfoil portion vibrate, having sliding occur between peak portions of an elastic portion, which are pressed against the shroud portions, and the shroud portions;
• and
• an energy-converting step of converting, by the sliding having occurred in the sliding- occurring step, vibrational energy of the vibration into frictional energy that occurs between the shroud portions and the elastic portion,
• wherein the elastic portion extends parallel to the direction in which a plurality of the shroud portions form a row and is a plurality of plate-like springs each formed in substantially a wave shape, and
• wherein the shroud portions with which the peak portions of a first spring are not in contact are in contact with the peak portions of the other spring, whereby all of the shroud portions are in contact with the springs.