add_filter( 'woocommerce_product_description_heading','product_description_tab', 10, 1 );

function product_description_tab( $title ) {
global $post, $product;
$brands = wp_get_post_terms( get_the_ID(), 'pwb-brand' );
    foreach( $brands as $brand )
return $post_excerpt = $brand->name.' - '. $post->post_title;
}