custom texonomy on div class unlinked for isotope

 // unlink category for portfolio category on div class
 function ar_texos_unlinked(){
    $terms = get_the_terms( $post->ID, 'ar_portfolio_cat' );

    if ( $terms && ! is_wp_error( $terms ) ) :

            $draught_links = array();

            foreach ( $terms as $term ) {
                    $draught_links[] = $term->name;
            }

            $draught_links = str_replace(' ', '_', $draught_links);


            $on_draught = join( " ", $draught_links );
            $on_draught = strtolower($on_draught);

    endif;

    echo $on_draught;
}

// use
<?php ar_texos_unlinked(' ');?>