Yes when a material is put under a tensile stress field, there can be a negative pressure.

When it comes to measuring air pressure in a room or experiment chamber, I don't think there is such thing as negative pressure. This is because we are comparing the pressure to vacuum, which is 0. However, values can be negative when they are compared to a different reference. For example, say you are doing an experiment to measure how much compression a material can withstand until a permanent deformation is observed. Compression would be measured by applying a positive pressure or force, while a tension experiment would be pulling. So tension could be represented with a negative force on the material (and remember that force = pressure * area). In this case, the "0" reference would be applying no forces to the material being tested.

Pressure is force per unit area. Force is a vector quantity; it has a direction. Thus, pressure against something means force against something, and thus pressure is also a vector quantity. Negative pressure thus works the same way as negative force: it is pressure in the opposite direction.

It gets more complicated when you have pressure on a spherical or other enclosed body, but you can still have pressure inside or pressure outside. For example, in a space ship, the pressure of the air inside the ship is pressing outward on the hull. In a submarine, the pressure of the water is pressing inward.

Negative pressure generally refers a place where pressure is smaller in one place relative to another place. It doesn't refer to the actual or static pressure being negative since that cannot go lower than zero. You will often hear about negative room pressure. Jan 31, 2013.