The design of a composite firstly depends on the environment of its application, including temperature, atmosphere, stress, and other functions if required. Then you can choose proper matrix material, and the reinforcement (fiber, particle, crystal whisker, etc).  The properties of the designed composite can be approximately calculated by the mixing rule  of composite materials. 

I hope that Bin Li is right

I also hope that Bin Lii is right

Fibers orientation, is one of important parameter to take into account.

For the purposes of this discussion, I assume you mean a high-performance fiber (e.g. glass, carbon or aramid) -reinforced polymer. 

Composites require care in the design and manufacturing process.  The following questions need to be considered in the design:

- Chemical compatibility between the matrix and the environment. (Fibers are also a concern, but generally are less sensitive than matrix materials.)

- Thermal and UV stability of matrix material (and aramid fibers).

- Mechanical requirements of finished composite (Aramids experience creep and buckle easily, but have higher specific strength than any other fiber. Epoxies generally yield better mechanical properties, but their viscosity is high, limiting part size.)

- Fiber/Fabric type (Fabrics have "efficiency", which is a derating based on the weave as compared to a single tow.  Satin fabrics have higher efficiency and better 'drape', whereas plain weaves tend to move less as the composite is de-aired and cured.)

- Laminate design (Most designs are what we call 'balanced' and symmetric.  This simplifies the couplings between linear and curvature strains.  Also avoid 'ply blocking - e.g. choose 0/90/0/90/0/90/0 instead of 0/0/90/90/90/0/0.  Blocked plys contribute to delamination at the edges.)

Manufacturing considerations:

- Layup method (prepreg or infiltration)

- Tool design (most tools are single-sided, with the other side of the part being defined by the interaction between the vacuum bag and the stacked layers)

- Cure cycle (Ensure complete wetting and de-gassing and complete crosslinking without excessive exotherm, which can cause 'burning'. )

- Vacuum distribution (All high-performance composites are vacuum de-gassed.  Multiple ports may be necessary to distribute vacuum properly.  Once part is initially de-gassed (and infiltrated, in the case of VARTM designs), standard practice is to close off the vacuum lines and monitor the vacuum to see that the bag is truly sealed. )

- Quality (Fabric cut tolerances, avoiding inclusions/contamination. For example, hand lotion used by operators has caused delamination of contaminated plys.)

- Testing, non-destructive and destructive to confirm quality manufacture and that the composite is meeting the mechanical requirements of the application.

I'm sure I've forgotten plenty here, but these are important considerations.

Remember that the mechanical properties of the composite are a function of the mechanical properties of the fiber, the matrix and the interface between them.  The interface is particularly critical, which drives careful consideration of the sizing of the fibers/tows.

Equally critical is the examination of the composite post-test.  Calculate the theoretical 'critical length' of the fibers and confirm that the fibers in the failed part are approximately this length.  Confirm also that the matrix failures are cohesive, rather than adhesive. 

Andrew slanker, thanks for such useful information,do you have some literature on considerations while preparing MMC and something about their interface ,how to develop strong interface

I studied mostly PMCs, but some of the same recommendations apply.  In addition, many metal matrices will react with ceramic reinforcing fibers at MMC processing temperatures.  I was able to find a good introduction to MMCs which mentions some of the specific issues relative to their manufacture.

https://www.princeton.edu/~ota/disk2/1988/8801/880107.PDF

Mostly MMC 's have light metals as a matrix and ceramics as reinforcement. A wettability study is recommended to study the interfacial strength. If not wettable surface treatment on reinforcements is recommended.

The term "composite" refers to a material that is a mixture of two or more materials which do not combine chemically, and the resulting material has performance by aggregating the performance contributions of materials mixed.

In other words, in a composite material in which we have used two materials, one with good tensile strengths and the another with good resistance to compression, mixture is produced so that, in compression to benefit from the material with superior performance in compression and in tension to benefit from the material with tensile good performance.

This principle can be applied to any combination of properties needed.

In construction, often the term "composite" is confused with "hybrid".

Usual, the rules of mixture should be a start point, but, because there are different ratios for materials used, laboratory evaluations are needed. Performance design based on experimental analysis is the best approach. Once you have established through many experimental determinations, the equation of evolution of performance, then it can be offered as a standardized rule.