5.1 Susceptibility to damage from concentrated out-of-plane forces is one of the major design concerns of many structures made of advanced composite laminates. Knowledge of the damage resistance properties of a laminated composite plate is useful for product development and material selection.
5.2 QSI testing can serve the following purposes:
5.2.1 To simulate the force-displacement relationships of impacts governed by boundary conditions (1-7).5 These are typically relatively large-mass low-velocity hard-body impacts on plates with a relatively small unsupported region. Since the test is run slowly in displacement control, the desired damage state can be obtained in a controlled manner. Associating specific damage events with a force during a drop-weight impact test is often difficult due to the oscillations in the force history. In addition, a specific sequence of damage events may be identified during quasi-static loading while the final damage state is only identifiable after a drop-weight impact test.
5.2.2 To provide an estimate of the impact energy required to obtain a similar damage state for drop-weight impact testing if all others parameters are held constant.
5.2.3 To establish quantitatively the effects of stacking sequence, fiber surface treatment, variations in fiber volume fraction, and processing and environmental variables on the damage resistance of a particular composite laminate to a concentrated indentation force.
5.2.4 To compare quantitatively the relative values of the damage resistance parameters for composite materials with different constituents. The damage response parameters can include dent depth, damage dimensions and through-thickness locations, Fmax , Ea, and Emax, as well as the force versus indenter displacement curve.
5.2.5 To impart damage in a specimen for subsequent damage tolerance tests, such as Test Method D7137/D7137M.
5.2.6 To measure the indentation response of the specimen with and without bending using the two specimen configurations (edge supported and rigidly backed).
5.3 The properties obtained using this test method can provide guidance in regard to the anticipated damage resistance capability of composite structures of similar material, thickness, stacking sequence, etc. However, it must be understood that the damage resistance of a composite structure
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