GMW GMW16652 PDF

Note: Nothing in this standard supercedes applicable laws and regulations.

Note: In the event of conflict between the English and domestic language, the English language shall take precedence.

These methods provide a way of obtaining physical response properties for static tension, long term creep and thermal expansion. The test data permits a design analyst to characterize the physical behavior in a material model in finite element analysis. The scope is restricted to the characterization of injection molded glass-fiber reinforced thermoplastic materials used in parts with long flow lengths. Typical applications include intake manifolds, oil pans and front covers. The methods appear as follows:

• Test Method A – Tensile Properties. Tensile properties is the method to evaluate the tensile properties of test specimens cut from an injection molded thermoplastic in the 0 Flow direction, 45 Flow direction, and 90 Flow direction at multiple temperatures.

• Test Method B – Tensile Creep Properties. Tensile creep properties describes the method to evaluate creep properties of test specimens cut from an injection molded thermoplastic plaques in the 0 Flow direction, and 90 Flow direction at multiple temperatures.

• Test Method C – Thermal Expansion Properties. Thermal expansion properties describes the method to evaluate thermal expansion between -40 °C and +150 °C, in the 0 Flow direction, 45 Flow direction, 90 Flow direction, and thickness direction.

Purpose. The effects of glass fiber orientation and large thermal transitions are captured using these test methods so that simulations can accurately reflect these behaviors. Finite element analysis using material models defined using the test data from the test methods described herein is used to simulate and, therefore, predict the mechanical deformation and failure of injection molded glass-fiber reinforced thermoplastic parts with long flow lengths.

Foreword. General Motors Research showed that a structural analysis which uses the orthotropic material model predicts well the deformation and failure characteristics of injection molded glass-fiber reinforced thermoplastic parts with long flow lengths, such as intake manifolds, oil pans, front covers. This included rubber modified and non-rubber modified materials. The requirements for this analysis are:

a. Predicting the average fiber orientation in the part, and

b. Fitting the mechanical properties obtained as described in this test method to determine the orthotropic constants.

Applicability. The data obtained is to be used for finite element analysis of injection molded non-impact and impact modified short glass – fiber reinforced thermoplastic parts of long flow length. The non-impact modified and modified impact glass – fiber reinforced thermoplastic must have glass fibers of length smaller than 3 mm (0.125 in). The methods are intended for rigid, low failure strain materials.