Rail Shear Tester Apparatus with multiple loading configurations

A testing apparatus for measuring a shear strength of a panel specimen including a first loading configuration and a second loading configuration, said panel specimen having a specimen width, a specimen length and a specimen thickness and having an unclamped area approximately rectangular in shape centrally located in said specimen width and a specimen center located at the middle of said panel specimen width and said specimen length, said apparatus including:

• a. an upper clamp means connected through an upper clamp pivot means, said upper clamp pivot means located on a first preferred loading angle and defining a first rotational degree of freedom about a horizontal axis perpendicular to said first preferred loading angle,
• b. said first preferred loading angle is a preferred diagonal line extending from corner to corner of said unclamped area of said panel specimen and extending outwardly therefrom,
• c. said upper clamp pivot means connected through a load cell to a load cylinder means, said upper clamp means supported by roller means running on angled roller rail means,
• d. Said load cylinder means mounted on a framework means,
• e. said load cylinder means, said load cell, and said angled roller rail means aligned parallel with said first preferred loading angle,
• f. means for measuring a displacement of said upper clamp means,
• g. a lower clamp means connected through a lower clamp pivot means to said framework means, said lower clamp pivot means located on said first preferred loading angle and allowing a second rotation degree of freedom about a horizontal axis perpendicular to said first preferred loading angle,
• h. a lower clamp support means including a lift means and a motion limiting means for selectively restraining rotation of said lower clamp means about said lower clamp pivot means,
• i. a control means for controlling a testing process,
• said testing apparatus providing selectable loading configurations whereby a shear force is applied along said first preferred loading angle with a first loading configuration with said second rotational degree of freedom in said lower clamp means about said lower clamp pivot means and a second loading configuration in which said motion limiting means prevents rotation about said lower clamp pivot means whereby said shear strength is determined from a maximum value of said shear force applied at failure of said panel specimen and a cross sectional area of a shear plane.