STIS - Stiffness testing / Ring Bending

Initial Specific Ring Stiffness, Resistance to Deflection and Creep

YLE stiffness (STIS) testers are leaders in the fiberglass (FRP, GRP and GRE) pipe industry.

Test standards compliance

YLE stiffness testing equipment complies with the following test standards:

Initial specific ring stiffness, STIS
ISO 7685
DIN EN 1228
ASTM D 2412
DIN 53769-3

Resistance to deflection
ISO 10466
DIN EN 1226
ASTM D 2412

Resistance to creep
DIN 16868-2
DVGW 24-hour
DVGW 100-hour

Stiffness testing equipment

Depending of maximum pipe size a number of alternatives exist of measuring initial specific ring stiffness, resistance to deflection and creep of fiberglass pipes:

CK stiffness testing machines: DN ≤ 4000

YLE's CK are the leading stiffness testers in the fiberglass pipe industry for testing pipes of DN 50 to DN 4000. Two standard models exist:

CK3200: For testing pipes of OD up to 3200 mm (125 inches)
CK4400 For testing pipes of OD up to 4400 mm (172 inches)

SLRS - Specimen lifting and rotation system

Manipulation of stiffness specimens of 3000 mm diameter and greater requires more than one operator for handling specimen during loading and testing and poses a serious risk hazard. For example, a 4 meter pipe stiffness ring has a weight exceeding 400 Kg, a slenderness ratio greater than 13, and a center of gravity 2 meters high. The handling of such specimens poses serious safety risks. To address this hazard, YLE developed the Specimen Lifting and Rotation System (SLRS) which is incorporated as standard in CK4400 machines and is offered as an option on CK3200 machines. In addition to addressing safety concerns, the SLRS provides improved user-friendliness and productivity.

A CK4400 with SLRS won the Innovation Award of the 2014 Shanghai Composites Expo.

Specifications CK3200 Specifications CK4400