Pultruded fibrous composite strips having non-planar profiles cross-section for wind turbine blade spar caps

A pultruded fibrous composite strip for stacking with one or more similar strips to form a spar cap of a wind turbine rotor blade, the strip being of substantially constant cross-section defined by first and second mutually opposed and longitudinally extending sides and by first and second longitudinal edges, the first and second sides comprising, respectively, first and second abutment surfaces,

• wherein the first and the second abutment surfaces are non-planar and curve toward a center of the wind turbine rotor blade or are angled toward the center of the wind turbine rotor blade;
• wherein the first side is proximate the center of the wind turbine rotor blade and further comprises two peripheral surface regions of the first side each extending longitudinally and wherein the first abutment surface is limited between the two peripheral surface regions of the first side and separated from the first and second longitudinal edges by the two peripheral surface regions of the first side;
• wherein the second side is distal to the center for the wind turbine rotor blade and further comprises two peripheral surface regions of the second side each extending longitudinally and wherein the second abutment surface is limited between the two peripheral surface regions of the second side and separated from the first and second longitudinal edges by the two peripheral surface regions of the second side;
• wherein the two peripheral surface regions of the second side each have a width measured along the second side and perpendicular to the longitudinal axis, wherein the width is between 2% and 10% of a distance separating the first longitudinal edge and the second longitudinal edge;
• wherein the two peripheral surface regions of the second side are chamfered;
• wherein the two peripheral surface regions of the first side are not chamfered;
• and
• wherein each of the first and second longitudinal edges extend from a respective peripheral surface region of the first side to a respective peripheral surface region of the second side and are not perpendicular to the peripheral surface regions.