foreach ($order_items as $oi) {
$_product = Mage::getModel('catalog/product')->loadByAttribute('sku', $oi->getSku());
$_product = Mage::getModel('catalog/product')->load($_product->getId());
if ($_product->getTypeId() == 'bundle') {
$options = $oi->getProductOptions();
$optionIds = array_keys($options['info_buyRequest']['bundle_option']);
$selectionCollection = $_product->getTypeInstance(true)->getSelectionsCollection(
$_product->getTypeInstance(true)->getOptionsIds($_product), $_product
);
$selected_skus = '' ;
foreach($selectionCollection as $option)
{
if( in_array($option->getData('option_id'), $optionIds)) {
$selected_skus .= $option->getSku() . ',' ;
}
}
echo $selected_skus ;
}
}