Core-crush resistant fabric and prepreg for fiber reinforced composite sandwich structures

A fiber reinforced composite structure, comprising:

• a laminate adhered to a core, said laminate being formed from at least one core crush resistant prepreg, said prepreg comprising:
• a woven fabric impregnated with a hardenable polymeric resin composition,
• said woven fabric having an areal weight of from about 150 to about 400 grams per square meter and consisting essentially of a plurality of carbon fiber tow stands in a first direction interweaving with a plurality of carbon fiber tow strands in a second direction, said tow strands in said first direction having a different tow construction from said tow strands in said second direction,
• wherein said prepreg has a tow aspect ratio of no greater than about 13.0 in said first direction and a tow aspect ratio of at least 13.5 in said second direction, and a prepreg openness of no greater than 4.0%.

A fiber reinforced composite structure comprising:

• a laminate adhered to a core, said laminate being formed from at least a core crush resistant prepreg, said prepreg comprising:
• a woven fabric consisting essentially of carbon fiber tow strands impregnated with a hardenable polymeric resin composition, said tow strands having a predetermined substantially stable non-round cross-sectional shape,
• said fabric having an areal weight of from about 150 to about 400 grams per square meter,
• said prepreg having an average tow aspect ratio of from about 12.0 to about 14.5, and a prepreg openness of no greater than about 4.0%.

A fiber reinforced composite structure, comprising:

• a laminate adhered to a core, said laminate being formed from at least one core crush resistant prepreg, said prepreg comprising:
• a woven fabric having a plain weave pattern consisting essentially of carbon fiber tow strands impregnated with a hardenable polymeric resin composition comprising an epoxy resin;
• said fabric having an areal weight of from about 180 to about 205 grams per square meter;
• each of said tow strands having a total filament count of about 3,000;
• said resin composition having an average epoxy functionality of greater than 2.0, and a tan δ of from about 0.5 to about 2.0 throughout the elevated temperature range of from about 70 to about 140° C.;
• and
• said prepreg having an average fiber tow aspect ratio of less than about 13.0, and a prepreg openness of from about 1.5% to about 10.0%.

A fiber reinforced composite structure, comprising:

• a laminate adhered to a core, said laminate being formed from at least one core crush resistant prepreg, said prepreg comprising:
• a woven fabric having a plain weave pattern consisting essentially of carbon fiber tow strands impregnated with a hardenable polymeric resin composition comprising an epoxy resin;
• said fabric having an areal weight of from about 180 to about 205 grams per square meter;
• each of said tow strands having a total filament count of about 3000;
• said resin composition having an average epoxy functionality of greater than 2.0, and a tan δ of from about 0.5 to about 2.0 throughout the elevated temperature range of from about 70 to about 140° C.;
• and
• said prepreg having an average fiber tow aspect ratio of less than about 13.0, a prepreg thickness of at least about 0.260 mm, and a prepreg openness of from about 1.0% to about 10%.

A fiber reinforced composite structure, comprising:

• a laminate adhered to a core, said laminate being formed from at least one core crush resistant prepreg, said prepreg comprising:
• a woven fabric consisting essentially of carbon fiber tow strands impregnated with a hardenable polymeric resin composition;
• said fabric having an areal weight of from about 150 to about 250 grams per square meter;
• said tow strands having a total filament count of from about 1,000 to less than about 3,000;
• and
• said prepreg having an average fiber tow aspect ratio of less than about 15.5, an average thickness of at least about 0.220 mm, and an openness of from about 1.0 percent to about 6.0 percent.

A fiber reinforced composite structure, comprising:

• a laminate adhered to a core, said laminate being formed from at least one core crush resistant prepreg, said prepreg comprising:
• a woven fabric consisting essentially of carbon fiber tow strands impregnated with a hardenable polymeric resin composition;
• said fabric having an areal weight of from about 150 to about 400 grams per square meter;
• said tow strands having a total filament count of greater than about 3,000 but no greater than about 18,000;
• and
• said prepreg having an average thickness of at least about 0.260 mm and an openness of at least about 1.5 percent.

A fiber reinforced composite structure comprising:

• a laminate adhered to a core, said laminate being formed from at least one core crush resistant prepreg, said prepreg comprising:
• a woven fabric impregnated with a hardenable polymeric resin composition;
• said woven fabric having an areal weight of from about 150 to about 400 grams per square meter and consisting essentially of a plurality of carbon fiber tow strands in a first direction interweaving with a plurality of carbon fiber tow strands in a second direction, said tow strands in said first direction having a different tow construction from said tow strands in said second direction;
• wherein said prepreg has a tow aspect ratio of no greater than about 13.0 in said first direction and a tow aspect ratio of at least 13.5 in said second direction, and a prepreg openness of no greater than 5.0%.

A fiber reinforced composite structure, comprising:

• a laminate adhered to a core, said laminate being formed from at least one core crush resistant prepreg, said prepreg comprising:
• a woven fabric impregnated with a hardenable liquid epoxy resin composition,
• said woven fabric having an areal weight of from about 185 to about 205 grams per square meter and consisting essentially of a plurality of carbon fiber tow strands in a first direction interweaving with a plurality of carbon fiber tow strands in a second direction, said tow strands in said first direction having a different tow construction from said tow strands in said second direction,
• wherein said prepreg has a tow aspect ratio of no greater than about 11.0 in said first direction and a tow aspect ratio of at least 15.5 in said second direction, a prepreg openness of no greater than 3.0%, and a prepreg thickness of from about 0.250 mm to about 0.280 mm.

A fiber reinforced composite structure, comprising:

• a laminate adhered to a core, said laminate being formed from at least one core crush resistant prepreg, said prepreg comprising:
• a woven fabric consisting essentially of carbon fiber tow strands impregnated with a hardenable polymeric resin composition, said tow strands having a predetermined substantially stable non-round cross sectional shape;
• said fabric having an areal weight of from about 150 to about 400 grams per square meter;
• said prepreg having an average tow aspect ratio of from about 8 to about 18, and a prepreg openness of no greater than about 5.0%.

A fiber reinforced composite structure, comprising:

• a laminate adhered to a core, said laminate being formed from at least one core crush resistant prepreg, said prepreg comprising:
• a woven fabric consisting essentially of carbon fiber tow strands impregnated with a hardenable polymeric resin composition comprising an epoxy resin, said tow strands having a predetermined substantially stable non-round cross sectional shape and a filament count of about 3,000;
• said fabric having an areal weight of from about 180 to about 205 grams per square meter;
• said prepreg having an average tow aspect ratio of from about 12.5 to about 14.0, a prepreg openness of no greater than about 3.0%, and a prepreg thickness of from about 0.250 mm to about 0.280 mm.