Abstract: An apparatus (100) for fatigue testing test articles (104) including wind turbine blades. The apparatus (100) includes a test stand (110) that rigidly supports an end (106) of the test article (104). An actuator assembly (120) is attached to the test article (104) and is adapted for substantially concurrently imparting first and second forcing functions in first and second directions on the test article (104), with the first and second directions being perpendicular to a longitudinal axis. A controller (130) transmits first and second sets of displacement signals (160, 164) to the actuator assembly (120) at two resonant frequencies of the test system (104). The displacement signals (160, 164) initiate the actuator assembly (120) to impart the forcing loads to concurrently oscillate the test article (104) in the first and second directions. With turbine blades, the blades (104) are resonant tested concurrently for fatigue in the flapwise and edgewise directions.

Abstract: An apparatus (10) for applying at least one load to a specimen (12) according to one embodiment of the invention may comprise a mass (18). An actuator (20) mounted to the specimen (12) and operatively associated with the mass (18) moves the mass (18) along a linear displacement path (22) that is perpendicular to a longitudinal axis of the specimen (12). A control system (26) operatively associated with the actuator (20) operates the actuator (20) to reciprocate the mass (18) along the linear displacement path (22) at a reciprocating frequency, the reciprocating frequency being about equal to a resonance frequency of the specimen (12) in a test configuration.

Abstract: An apparatus (100) for fatigue testing test articles (104) including wind turbine blades. The apparatus (100) includes a test stand (110) that rigidly supports an end (106) of the test article (104). An actuator assembly (120) is attached to the test article (104) and is adapted for substantially concurrently imparting first and second forcing functions in first and second directions on the test article (104), with the first and second directions being perpendicular to a longitudinal axis. A controller (130) transmits first and second sets of displacement signals (160, 164) to the actuator assembly (120) at two resonant frequencies of the test system (104). The displacement signals (160, 164) initiate the actuator assembly (120) to impart the forcing loads to concurrently oscillate the test article (104) in the first and second directions. With turbine blades, the blades (104) are resonant tested concurrently for fatigue in the flapwise and edgewise directions.

Abstract: A method and apparatus for controlling frame rise on a heavy duty truck having a frame, a drive axle connected to the frame, and a selectively lockable suspension component disposed therebetween for maintaining the relative position therebetween. Signals indicative of at least one of the following vehicle operating parameters: engine speed, brake pressure, vehicle speed, air bag pressure, steering wheel angle, vehicle height, or throttle position are monitored and a predicted thrust is calculated that will be applied to the drive axle based on the monitored signals. The selectively lockable suspension component is locked if the predicted thrust exceeds a predetermined threshold and is also controlled with respect to other operating parameters such as whether vehicle brakes are applied, any instantaneous change in torque, vehicle operating speed, and the length of time the selectively lockable suspension component has been locked.

Abstract: An apparatus (10) for applying at least one load to a specimen (12) according to one embodiment of the invention may comprise a mass (18). An actuator (20) mounted to the specimen (12) and operatively associated with the mass (18) moves the mass (18) along a linear displacement path (22) that is perpendicular to a longitudinal axis of the specimen (12). A control system (26) operatively associated with the actuator (20) operates the actuator (20) to reciprocate the mass (18) along the linear displacement path (22) at a reciprocating frequency, the reciprocating frequency being about equal to a resonance frequency of the specimen (12) in a test configuration.

Abstract: A method for controlling the ride height in a suspension of an over the highway truck or tractor based on rear axle load. A load on the rear axle is measured. An optimum ride height is calculated at core response to correct drive lighted angles based on the rear axle load. The actual ride height is measured. The difference between the optimum ride height and the actual ride height is calculated. A component of the suspension, such as an air spring, is adjusted to adjust the actual ride height to a height closer to the optimum ride height.

Abstract: A rear axle suspension for a highway truck that includes a pair of trailing arms suspended below a frame by a pair of hanger brackets. The hanger brackets define a pivot axis for the trailing arms. A supplemental axle locating member is attached to the axle and includes an extension member that in engageable with a bracket held by the frame. The hanger brackets are laterally compliant and each comprise an inner and outer plate, one of which is bent outwardly to define a gap within which an associated trailing arm is mounted. A moment canceling member extends between the hanger brackets and resists outward bending of the brackets. A height control valve is operated by an operating rod having an axis that passes through, or in close proximity, to the roll center of the vehicle in order to reduce ride height errors.

Abstract: A method and apparatus for adaptively damping relative motion between the wheels and the frame of a heavy duty truck having a frame suspended on wheels by a suspension system. An air spring is disposed between the frame and at least one of the wheels having a primary reservoir for holding air and a piston adapted to act upon the air in the reservoir to compress the air and thereby provide support for the frame. An auxiliary reservoir holds air and can be placed in fluid communication with the primary reservoir to increase an effective volume of air upon which the piston acts. A control valve selectively places the auxiliary reservoir in communication with the primary reservoir based on vehicle operating parameters. The control valve can be actuated mechanically by forces acting on the wheels or by a controller that controls the valve based on wheel torque and road roughness.

Abstract: A bracket formed from a single piece of sheet material for use in suspension of a vehicle for inhibiting relative lateral movement between and axle and a frame of the vehicle. The bracket includes a first portion bent to form a sleeve for insertion of a first fastener used to mount a first end of a torque rod. A second portion of the sheet material is bent to form a second sleeve for insertion of a second fastener used to mount the first end of the torque rod. A base portion is formed from the sheet material for mounting the bracket to the axle of the vehicle. The base portion maintains the first sleeve and the second sleeve in a spaced apart relationship for mounting an end of the torque rod.

Abstract: A method for controlling the ride height in a suspension of an over the highway truck or tractor based on rear axle load. A load on the rear axle is measured. An optimum ride height is calculated at core response to correct drive lighted angles based on the rear axle load. The actual ride height is measured. The difference between the optimum ride height and the actual ride height is calculated. A component of the suspension, such as an air spring, is adjusted to adjust the actual ride height to a height closer to the optimum ride height.

Abstract: A method and apparatus for controlling frame rise on a heavy duty truck having a frame, a drive axle connected to the frame, and a selectively lockable suspension component disposed therebetween for maintaining the relative position therebetween. Signals indicative of at least one of the following vehicle operating parameters: engine speed, brake pressure, vehicle speed, air bag pressure, steering wheel angle, vehicle height, or throttle position are monitored and a predicted thrust is calculated that will be applied to the drive axle based on the monitored signals. The selectively lockable suspension component is locked if the predicted thrust exceeds a predetermined threshold and is also controlled with respect to other operating parameters such as whether vehicle brakes are applied, any instantaneous change in torque, vehicle operating speed, and the length of time the selectively lockable suspension component has been locked.

Abstract: A method and apparatus for adaptively damping relative motion between the wheels and the frame of a heavy duty truck having a frame suspended on wheels by a suspension system. An air spring is disposed between the frame and at least one of the wheels having a primary reservoir for holding air and a piston adapted to act upon the air in the reservoir to compress the air and thereby provide support for the frame. An auxiliary reservoir holds air and can be placed in fluid communication with the primary reservoir to increase an effective volume of air upon which the piston acts. A control valve selectively places the auxiliary reservoir in communication with the primary reservoir based on vehicle operating parameters. The control valve can be actuated mechanically by forces acting on the wheels or by a controller that controls the valve based on wheel torque and road roughness.

Abstract: A bracket formed from a single piece of sheet material for use in suspension of a vehicle for inhibiting relative lateral movement between and axle and a frame of the vehicle. The bracket includes a first portion bent to form a sleeve for insertion of a first fastener used to mount a first end of a torque rod. A second portion of the sheet material is bent to form a second sleeve for insertion of a second fastener used to mount the first end of the torque rod. A base portion is formed from the sheet material for mounting the bracket to the axle of the vehicle. The base portion maintains the first sleeve and the second sleeve in a spaced apart relationship for mounting an end of the torque rod.